research article logarithmic slots antennas using...
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Research ArticleLogarithmic Slots Antennas Using SubstrateIntegrated Waveguide
Jahnavi Kachhia Amit Patel Alpesh Vala Romil Patel and Keyur Mahant
Department of Electronics and Communication Engineering Charotar University of Science amp Technology ChangaAnand Gujarat India
Correspondence should be addressed to Amit Patel amitvpateleccharusatacin
Received 29 May 2015 Revised 24 August 2015 Accepted 13 September 2015
Academic Editor Xianming Qing
Copyright copy 2015 Jahnavi Kachhia et alThis is an open access article distributed under theCreativeCommonsAttribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited
This paper represents new generation of slotted antennas for satellite application where the loss can be compensated in terms ofpower or gain of antenna First option is very crucial because it totally depends on size of satellite so we have proposed the high gainantenna creating number of rectangular trapezoidal and I shape slots in logarithm size in Substrate Integrated Waveguide (SIW)structure The structure consists of an array of various shape slots antenna designed to operate in C and X band applications Thebasic structures have been designed over a RT duroid substrate with dielectric constant of 22 and with a thickness of 0508 mmMultiple slots array and shape of slot effects have been studied and analyzed using HFSS (High Frequency Structure Simulator)The designs have been supported with its return loss gain plot VSWR and radiation pattern characteristics to validate multibandoperation All the proposed antennas give gainmore than 9 dB and return loss better than minus10 dB However the proposed structureshave been very sensitive to their physical dimensions
1 Introduction
Rapid development in the field of wireless communicationsystem that operates in the microwave range is payed moreattention from industry and academia [1ndash3] In the presentrectangular waveguides are widely used in microwave engi-neering for antenna [4] filters [5 6] couplers [7] and so forthdue to their advantages of low losses high power handlingand high isolation [8] In addition slot array antennas basedon waveguides that feature favorable antenna performancesuch as high directivity low cross-polarization and low cross-talk have been presented [9 10 15]
In 1943 the slot arraywas invented atMcGill University inMontreal by Watson One of the best features of this antennais horizontal polarization and omnidirectional gain aroundthe azimuth A slot along the length is cut into the wall of awaveguide that disrupts the transverse current flowing in thewall which enforces the current to travel at border of the slotand induces an electric field in the slot [11 12]The location ofthe slot in the rectangular waveguide decides the current flowThus the pose determines the impedance introduced to thetransmission line and the amount of energy coupled and radi-ated from the slot Slottedwaveguide arrays (SWA) have some
advantages over microstrip antennas such as having low losshigh isolation and high power handling [11] Due to theseadvantages SWA antennas are widely used in communica-tion and radar systems particularly at microwave wave fre-quencies Regarding conformal array applicationsmicrostripantennas are easier to implement compared to SWA anten-nas however excitation of antenna elements by a waveg-uide feed network is advantageous compared to micros-trip feed network in terms of eliminating radiation losses andcross coupling problems Moreover complex feed networkstructure is not needed in SWA to excite the slots in thesame waveguide Furthermore the array of waveguides canbe formed without cross coupling problems
However the manufacturing of these waveguides needsto be accomplished with sufficient accuracy so as to allowfor operation at millimeter wave frequencies On the otherhand antennas and microwave components used at lowerfrequencies typically rely on planar designs which are mostlyrealized with the Printed Circuit Board (PCB) processingtechnique [13 14] Moreover conformal arrays have a specificshape determined by the parameters other than radiationpattern and input match requirements and they can easily
Hindawi Publishing CorporationInternational Journal of Microwave Science and TechnologyVolume 2015 Article ID 629797 11 pageshttpdxdoiorg1011552015629797
2 International Journal of Microwave Science and Technology
be implemented using microstrip technology using a flexiblesubstrate or multifaceted surfaces [15]
This mature technology leads to not only low-costdesigns but also the possibility to easily integrate themwith common electronic components However these planardesigns are by nature not fully shielded and thus subject toradiation cross-talk and packaging problems [16] It has alsocomplex feed networks such as probes feeding patch ele-ments Strip line can be used to eliminate the radiation losseshowever cross coupling problems are encountered in the feednetwork with strip line structure These drawbacks added tothe potentially high conductor losses make this technologynot feasible to implement high frequency complex structuressuch as large feeding networks [17] It is then obvious that alarge performance gap exists between components based onmetallic waveguides and the ones based on PCBs
A very promising candidate to fill this gap and to providewidespread commercial solutions is the SIW technologyor more in general the Substrate Integrated Circuit (SIC)architecture [18] This technology allows building high per-formance low cost and reliable waveguide-like componentsusing planar processing techniques such as the PCB or theLow-Temperature Cofired Ceramic (LTCC) [19] It has alsounique features such as compact size in comparison withwaveguide antennas and also simpler structure in compari-son with reflector antennas [1]
On the basis of the above two SIW slot array antennashave been proposed with high gain and ultrawide bandwidthspecifically forC band X band andKuband applicationsTheproposed structures contain three different shapes of slotslike rectangle trapezoidal and I shape and its size variesaccording to logarithmvalueAll the structures generate quitebetter results and respond to resonant frequencies accordingto their size One of the unique features of them is that theygenerate sharp radiation pattern and isolation between bandsis much more high Due to these advantages the slotted SIWantennas are good candidates for the conformal array appli-cations especially when SIW is implemented using a flexiblesubstrate There is a limited study in the literature on theconformal array applications with slotted waveguide arrays
With the aim of the above the structure of paper isas follows Section 2 describes the theory of basic SIW andbased on it is the design of slotted linear arrays of antennaThen Section 3 shows the design and calculation of variousproposed antennas and their simulation results are shown inSection 4 Section 5 contains comparison of all the proposedantennas and discussion of results Finally paper is endedwith conclusion
2 SIW Antenna Design
SIW is described as two conducting layers are connected bycylindrical vias row at both sides which is shown in Figure 1[20] In Figure 1 119889 is the diameter of vias 119908 is the equivalentwidth of SIW 119901 is the spacing between two vias and ℎ is thethickness of substrate Structure of SIW contains low costhigh 119876-factor low radiation and high density integrationwhich makes it preferable
W
d
h
P
Dielectricsubstrate
Unit cell
Metal post
Top metallayer
Figure 1 Basic structure of SIW
The cutoff frequency of SIW is defined as 119891119888= 1198882119886
where 119886 is width of waveguide it can change by varying thewidth in conciliation of degrading the overall characteristicsof its components
As we know that the current in the walls of the waveguidemust be comparative to the difference in the electric fieldbetween two points (so the selection of slot in SIW is veryimportant) [21]Therefore tomake a slot in the correct centerof the broad wall of the waveguide will not radiate at all sincethe electric field is not asymmetrical around the center ofthe guide and thus is indistinguishable at both edges of theslot If the position of slot is moved from the centerline thedifference in field concentration between the rims of the slotis larger so that more current is interrupted andmore energyis coupled to the slot that ultimately increases radiated powerIn other sides of thewaveguide the field strength is veryweaksince the sidewalls are short circuited for the electric fieldThe produced current must also be small longitudinal slotswhich are far from the center or created in the sidewall willnot radiate significantly
In this paper we keep the distance between slots as 1205821198922
such that the slots will be fed in the same phase (spacingbetween the slots at 120582
1198922 intervals in the waveguide is an
equivalent electrical spacing of 180∘ Therefore each slot isexactly out of phase with its neighbors so their radiationcancelled each otherOn the other side slots on opposite sidesof the center axis of the guide are out of phase (180∘) so wecan swap the slot displacement around the center axis andhave a total phase difference of 360∘ between slots puttingthem back in phase) and the beam will not be inclined [22]For the position of the last slot the center of slot is kept atguided quarter wavelength away from the closed end of thewaveguide As we know that a short circuited quarter wave-length stub of transmission line works as an open-circuitthe closed end does not impact on the impedance Anotherreason to keep the closed end is space 3120582
1198924 for mechanical
fabrication the extra half-wavelength is crystal clear
3 SIW Slots Array Antenna Parameters
TheSIW slots array antenna is shown in Figure 2Here primeimportant parameters in the design are distance and diameterof posts which controlled the flow of electric field Slots are
International Journal of Microwave Science and Technology 3
a
p d
2l
l 3l4lwat
lt lw
a998400
Figure 2 Schematic of proposed antenna
30mm
15mm 553mm
Figure 3 Microstrip to SIW transition
2136mm1424mm3376mm
1702mm
9mm 10mm30mm
0508mm
Figure 4 Side and top view of 1st proposed logarithmic rectangularslots array antenna
printed on a 0508mm thick Roger RT duroid 5880 substrate(the relative dielectric constant is 22) with the size of 119882 times119871 = (3376 times 1702)mm The selection of feed is also veryimportant and here we have selected feeding using taperedslot which is shown in Figure 3 that provide transition frommicrostrip to SIW [23] A tapered microstrip line has thefollowing parameters the width of the feed line 119886
119905= 15mm
119908 = 553mm and the length of feed line 119897119905= 30mm
(calculation of all the parameters are shown below)The finiteground plane has an area of119882times119867 = (3376 times 1702)mm
Parameters Calculation [21](1) For designing SIW based antenna define first sub-
strate dimensions which are given by 119886 times 119887 for that119886
1015840 and 119886must be known as shown below (1198861015840 inverselypropositional to cutoff frequency)
119886
1015840
=
119888
2119891
119888radic120576
119903
(1)
(2) Now obtain center-to-center distance with the help of119886
1015840 as
119886 = 119886
1015840
+
119889
2
095119901
(2)
minus3500
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
625 750 875 1000 1125 1250 1375 1500
Freq (GHz)
m1
m2
m3m4
m5
m6
Curve info
Setup1 sweep
Name X Y
m1
m2
m3
m4
m5
m6
70500
102000
108500
119000
128000
146000
minus314424
minus124807
minus210062
minus238238
minus126106
minus263216
S11 (dB)
S 11
(dB)
Figure 5 11987811
of 1st proposed logarithmic rectangular slots arrayantenna
625 750 875 1000 1125 1250 1375 1500
Freq (GHz)
000
500
1000
1500
2000
2500
3000
3500
VSW
R(1
)
Curve infoVSWR(1)
Setup1 sweep
m1 m2 m3 m4 m5 m6
Name X Y
m1
m2
m3
m4
m5
m6
70500
102000
108500
119000
128000
146000
10550
16235
11955
11376
16114
11015
Figure 6 VSWR of 1st proposed logarithmic rectangular slots arrayantenna
(3) To select the diameter of post and also distancebetween two posts we have to consider the followingcondition which minimizes the losses [1]
119901 le 2119889
005 lt (
119901
120582
119888
) lt 025
120582
119892
5
lt 119889
(3)
where 120582119892is given by
120582
119892=
120582
119888
radic
120576
119903
(4)
Here 119901 is the center-to-center distance between twoposts 119889 is the diameter of the post 120582
119892is guided wave-
length 120582119888is cutoffwavelength 120576
119903is relative permittiv-
ity of dielectric medium(4) To apply tapper feed at antenna first find the tapper
width by using traditional microstrip calculationwhich is denoted by (119908
1) and after that feeding width
at dielectric side
4 International Journal of Microwave Science and Technology
2008001400
90
60
300
150
120
200
400
600800
90
60
300
150
120
160320480640
90
60
300
150
120
Antenna gain plot for 108GHz
Antenna gain plot for 119GHz
Antenna gain plot for 705GHz
Radiation pattern for solution frequency 119GHz
Radiation pattern for solution frequency 108GHz
Radiation pattern for solution frequency 705GHz
minus400
minus30
minus60
minus90
minus120
minus150minus180
minus30
minus60
minus90
minus120
minus150
minus180
minus30
minus60
minus90
minus120
minus150minus180
Curve inforETotal (dB)
Setup1 LastAdaptiveFreq = 705GHz Theta = 90degldquo ldquordquo rdquo
rETotalCurve info
Setup1 LastAdaptiveFreq = 1085GHz Theta = 90degldquo ldquordquo rdquo
Curve info
Setup1 LastAdaptiverETotal
Freq = 119GHz Theta = 90degldquo ldquordquo rdquo
71077e + 00050667e + 00030257e + 00098467e minus 001minus10563e + 000
minus51383e + 000minus71793e + 000minus92203e + 000minus11261e + 001minus13302e + 001minus15343e + 001minus17384e + 001minus19425e + 001minus21466e + 001minus23507e + 001minus25548e + 001
GainTotal (dB)
GainTotal (dB)
GainTotal (dB)
X
Y
Z
X
Y
Z
X
Y
Z
75069e + 00057476e + 00039883e + 00022290e + 00046965e minus 001minus12896e + 000minus30489e + 000minus48082e + 000minus65675e + 000minus83268e + 000minus10086e + 001minus11845e + 001minus13605e + 001minus15364e + 001minus17123e + 001minus18883e + 001minus20642e + 001
10685e + 001
40077e + 000
minus26697e + 000
minus93470e + 000
minus16024e + 001
minus22702e + 001
minus29379e + 001
minus30973e + 000
Figure 7 Continued
International Journal of Microwave Science and Technology 5
200
400600800
90
60
300
150
120
Antenna gain plot for 146GHz Radiation pattern for solution frequency 146GHz
minus30
minus60
minus90
minus120
minus150minus180
Curve info
Setup1 LastAdaptiverETotal
Freq = 146GHz Theta = 90degldquo ldquordquo rdquo
X
Y
Z
69798e + 00048590e + 00027382e + 00061746e minus 001minus15033e + 000minus36241e + 000minus57449e + 000minus78657e + 000minus99865e + 000minus12107e + 001minus14228e + 001minus16349e + 001minus18470e + 001minus20590e + 001minus22711e + 001minus24832e + 001minus26953e + 001
GainTotal (dB)
Figure 7 Gain plots and radiation patterns at different resonant frequencies
The width of tapper at feed side is 04 times the open-ing of patch antenna
119886
119905= 04 (119886 minus 119889) (5)
The width of tapper at antenna side is
119908 =
119888
2119891radic(120576
119903+ 1) 2
(6)
Finally length of tapper for impedance match is given by
119897
119905=
119899 lowast 120582
119892
4
where 119899 = 1 2 3 (7)
It is already derived that the gain and beamwidth formula forthe slots have equal distance end to end and spacing along thewaveguide A simple procedure to calculate the gain of a slotantenna is on array of dipoles As we double the dipole slotsthey increase the double gain So for 16 slots it is possible toget gain of 12 dB Each time we double the number of dipoleswe double the gain or add 3 dB Thus a 16-slot array wouldhave a gain of about 12 dB Gain can be calculated from theequation 119866 = 10 log(119873) dB for119873 total slots
Now include the effect of gain with spacing of slot betterto be described as
Gain = 10 log119873 lowast slotspacing120582
0
dB (8)
Calculated gain is always equal to average gain nowbeamwidth is given by
Beamwidth = 507120582
0
(1198732) lowast slotspacingDegree (9)
Table 1 Specification of the proposed structure
Parameters ValueCenter frequency 7GHzReturn loss gtminus10 dBVSWR 1Gain gt5 dBDielectric constant (RT duroid) 22
4 Design of Proposed Structures
Here we have considered the design of proposed structurebased on the specification given in Table 1 These specifi-cations are considered based on the satellite and RADARapplications in which we are targeting C X and Ku bandfrequencies The C band X band and Ku Band defined byan IEEE standard for radio waves and radar engineering withfrequencies that range from 40 to 80GHz 80 to 120GHzand 120 to 180GHz respectively Frequency range of 37 to42GHz is used for the satellite downlink communicationin C band and the band of frequencies from 5925GHz to6425GHz for their uplinks The X band is used for shortrange tracking missile guidance marine radar and airborneintercept It is used especially for radar communicationranges roughly from 829GHz to 114 GHz The Ku band isused for high resolution mapping and satellite altimetry Kuband especially is used for tracking the satellite within theranges roughly from 1287GHz to 1443GHz
From the above applications the proposed structuredesign is targeted at center frequency of 7GHz Physicaldimensions of the first proposed structure are calculated bythe above formula and summarized in Table 2 The wire linestructure of proposed antenna is shown in Figure 3
6 International Journal of Microwave Science and Technology
625 825 1025 1225 1425
minus35
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo63mmrdquob1 = ldquo1856mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1256mmrdquoa1f = ldquo425mmrdquoS11 (dB)
S11 (dB)
S11 (dB)
(a)
625 825 1025 1225 1425
minus45
minus40
minus35
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo73mmrdquob1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo53mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquoS11 (dB)
S11 (dB)
S11 (dB)
(b)
625 825 1025 1225 1425
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo63mmrdquob1 = ldquo1556mmrdquoa1f = ldquo525mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo325mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo225mmrdquoS11 (dB) S11 (dB)
S11 (dB)
(c)
Figure 8 (a) 11987811of logarithmic rectangular slots array antenna with respect to variations in 1st slot position (b) 119878
11of logarithmic rectangular
slots array antennawith respect to variations in 1st slot position (c) 11987811of logarithmic rectangular slots array antennawith respect to variations
in width of 1st slot
International Journal of Microwave Science and Technology 7
Table 2 Calculated parameters
Parameter 119891
119888119886
1015840
119863 119875 119886
119904120576
119903120582
119888120582
119892119908 119886
119905119897
119908119897
119905
Value 71 GHz 142mm 9mm 10mm 2276mm 22 4225mm 2848mm 5504mm 15mm 170mm 30mm
Table 3 Summaries of simulated parameters
Resonant frequency Gain in dB Bandwidth in MHz VSWR Peak return loss in dB705GHz 1085 100 105 minus31431085GHz 75 200 119 minus2100119 GHz 71 250 113 minus2371146GHz 69 400 1097 minus2664
As shown in Figure 4 it contains six rectangular slotsarray whose longitudinal length is varied according to log-arithmic manner We are keeping center-to-center distancebetween two slots as 1424mm (120582
1198922) and center of last slot
to broadside wall as 2136mmThe structure has been simulated using HFSS (High Fre-
quency Structure Simulator) and it generates return lossshown in Figure 5 As shown in Figure 5 the structure gen-erates six resonant frequencies one in C band (705GHz)three in X band (102 1055 and 115 GHz) and two inKu band (128 and 146GHz) respectively These results aretotally expected since the proposed antenna is composedof different resonant slot lengths providing the multibandperformance At all the resonant frequencies VSWR is alsogood which is shown in Figure 6 One of the extraordinaryperformances generated by this structure is shown in Figure 7which represents the gain value that is more than 10 dBin single layer and single array combination compared toother traditional antennas having multilayer and 2 to 3arrays for achieving higher gain Various gain and radiationpatterns of the proposed logarithmic slots array of antennafor different resonant frequencies are shown in Figure 6 Allthe simulation results are summarized in Table 3
It is possible to tune the frequency by changing the geo-metrical position with respect to wave propagation directionand physical dimensions of the slots All these methodsultimately changed the value of reactance of resonators andcoupling of the EM field Here we have demonstrated threepossible methods to tune the response (i) pose of slot (ii)length of slot (iii) width of slot For demonstration andanalysis purpose onlywe applied the above tuningmethods tothe first slot These methods can also be applicable for otherremaining slots Figure 8(a) demonstrates simulation resultof reflection coefficient obtained by changing the positionof first slot which was kept at 120582
1198922 distance with respect
to second slot in longitude direction It shows that whenwe move the slot position in positive longitude direction itimproves the value of return loss and increment in oppositedirection it reduces the value of return loss Figure 8(b)shows the simulation result with increasing the length of thefirst slot It decreases the values of inductance and increasesthe capacitance value Variation in length gave minor effecton a reflection coefficient value Similarly Figure 8(c) is theresult of reflection coefficient with the change in width of
1424mm4mm3376mm
1702mm
0508mm
2136mm
9mm 10mm30mm
Figure 9 2nd proposed structure contains I shape logarithmic slotsarray antenna
m3
m4
m5
m6
m7m8m9
m2 m10
m1
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
700 800 900 1000 1100 1200 1300 1400 1500600
Curve info
Setup1 sweep
Freq (GHz)
Name X Y
m1 77080m2 81210m3 84170m4 87660m5 92910m6 102010m7 104890m8 109930m9 118430m10 137490 minus124121
minus156759minus138911minus147592minus226325minus274168minus103236minus241340minus124315minus180066
S11 (dB)
S 11
(dB)
Figure 10 11987811plot for I shaped logarithmic slots array antenna
the first slot that tunes resonant frequency effectively and alsoproduces very sharp bandwidth
In the second proposed structure instead of takingrectangular shape slots longitudinal I shape is selected whichis shown in Figure 9 Spacing between two slots and centerdistance of last slots from the end boadsie wall are the same as1st proposed design In first I shape slot vertical height of theslot is 4mm and length of slot is 10mm which progressivelyincreases for other slots according to logarthmic nature
This structure is also simulated by using HFSS and itsreturn loss is shwon in Figure 10 This structure radiates atsix resonant frequencies one in C band (77 GHz) three inX band (812 841 876 929 102 1048 1099 1145 and
8 International Journal of Microwave Science and Technology
Y
Z
53483e + 00033392e + 00013301e + 000minus67903e minus 001minus26881e + 000minus46972e + 000minus67063e + 000minus87154e + 000minus10725e + 001minus12734e + 001minus14743e + 001minus16752e + 001minus18761e + 001minus20770e + 001minus22779e + 001minus24788e + 001minus26797e + 001
GainTotal (dB)
(a)
080
160
240
320
90
60
300
150
120
Curve inforETotal
Setup1 LastAdaptiveFreq = 71GHz Theta = 90degldquo ldquordquo rdquo
minus30
minus60
minus90
minus120
minus150minus180
(b)
Figure 11 (a) Gain plot and (b) radiation pattern for I shape logarithmic slots array antenna
1424mm 3376mm
1702mm
0508mm
9mm 10mm30mm
15mm 21mm
Figure 12 3rd proposed structure contains trapezoidal logarithmic slots array antenna
m2
m3
m4m5 m6
m7
m8m1
Curve info
Setup1 sweep
700 800 900 1000 1100 1200 1300 1400 1500600Freq (GHz)
minus3500
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
Name X Y
m1 67300m2 78400m3 103800m4 110700m5 114300m6 121400m7 128100m8 143600 minus183495
minus300236
minus181027minus163299
minus202328
minus270798
minus154970minus159939
S11 (dB)
S 11
(dB)
Figure 13 11987811plot for trapezoidal logarithmic slots array antenna
119 GHz) and two in Ku band (1395 and 145 GHz)The gainplot and radiation pattern for 67GHz frequency are shownin Figures 11(a) and 11(b) which shows that it generates gainof 5 dB which is half compared to first proposed structure
Third proposed structure contains trapezoidal logarith-mic slots array as shown in Figure 12 Distances of all the slots
m1 m2 m3 m4 m5 m6 m7 m8
700 800 900 1000 1100 1200 1300 1400 1500600Freq (GHz)
000500
100015002000250030003500
VSW
R(1)
Curve infoVSWR(1)
Setup1 sweep
Name X Ym1 67200 13759m2 78400 14037m3 103800 10926m4 110700 12157m5 114300 13601m6 121400 12842m7 128000 10823m8 143700 12861
Figure 14 VSWR of 3rd proposed trapezoidal logarithmic slotsarray antenna
are the same as 1st proposed design Simulated result of theproposed structure is shown in Figure 13 which shows higherreturn loss occurring at eight different frequencies two in Cband (67 and 754GHz) four in X band (1025 11 1143 and
International Journal of Microwave Science and Technology 9
10300e + 001
79774e + 000
33329e + 00056551e + 000
10107e + 000minus13115e + 000minus36337e + 000minus59560e + 000minus82782e + 000minus10600e + 001minus12923e + 001minus15245e + 001minus17567e + 001minus19889e + 001minus22211e + 001
minus26856e + 001
minus24534e + 001
GainTotal (dB)
Y
Z
(a)
Curve inforETotal
Setup1 LastAdaptiveFreq = 71GHz Theta = 90degldquo ldquordquo rdquo
minus30
minus90
minus120
minus150
minus180
minus60
200
400
600
800
90
60
300
150
120
(b)
Figure 15 (a) Gain plot and (b) radiation pattern for trapezoidal logarithmic slots array antenna
Figure 16 Fabricated model of logarithmic rectangular slots arrayantenna
5 10 15
minus30
minus25
minus20
minus15
minus10
minus5
0
Simulated S11 (dB)Measured S11 (dB)
Figure 17 11987811of logarithmic rectangular slots array antenna
1214GHz) and Ku band (1281 and 1436GHz) Its VSWR isshown in Figure 14Gain plot and radiation pattern are shownin Figures 15(a) and 15(b) respectively It gives more than10 dB gain at 67 GHz frequency
Simulated gainMeasured gain
00 30 60 90 120 150 180 210 240 270 300 360330
1
2
3
4
5
6
7
8
9
10
Figure 18 Gain of logarithmic rectangular slots array antenna
5 Measured Results
Logarithmic rectangular slots array antenna has been fabri-cated on Rogers RT Duroid 5880 high frequency substratewith a thickness of 0787mm relative permittivity of 22 andrelative permeability of 1 and loss tangent of 00009 The topside of the antenna has logarithmic slots and the other side isground planeThe photograph of fabricated antenna is shownin Figure 16
The antenna 11987811parameter and gain are measured using
the Vector Network Analyzer MVNA-8-350 with probe sta-tion The simulated and measured 119878
11parameter for antenna
is shown in Figure 17 A slight difference is observed between
10 International Journal of Microwave Science and Technology
Radiation efficiency
100
095
090
085
HFSSCurve info
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Radiation efficiency
Radiation efficiency
Setup1 LastAdaptiveFreq = 71GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Freq = 71GHz Theta = 10degldquo ldquordquo rdquo
Freq = 71GHz Theta = 20degldquo ldquordquo rdquo
Freq = 71GHz Theta = 50degldquo ldquordquo rdquo
Freq = 71GHz Theta = 40degldquo ldquordquo rdquo
Freq = 71GHz Theta = 60degldquo ldquordquo rdquo
Freq = 71GHz Theta = 30degldquo ldquordquo rdquo
(a)
Radiation efficiency
HFSS design2Curve info
096
092
088
084
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 10degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 20degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 50degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 40degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 60degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 30degldquo ldquordquo rdquo
(b)
Figure 19 Radiation efficiency of logarithmic rectangular slots array antenna in (a) C band and (b) X band
the measured value and simulated value The differencebetween the measured and simulated 119878
11of the antenna is
caused by the microstrip to SIW transitionThe simulated and measured gain of the antenna are
shown in Figure 18Themaximummeasured gain is also veryclose to 10 dB at 7GHz for the antenna which is max Themeasured result shows that the bandwidth of the antennacovers over 300MHz while the gain of the antenna is keptalmost constantwithin such awide bandwidth of the antennaSimulation results specify that metallic and dielectric lossesdo not have a substantial effect on the bandwidth andmatching condition of the antenna while they decrease themeasured gain of antenna by 05 dB The apparent differencebetween the simulation and measured gains might be dueto the calibration linked tolerance range of the antennareference in anechoic chamber
The radiation pattern of the antenna at resonant fre-quency is shown in Figure 18 The radiation pattern mea-surement is carried out in a conventional far field anechoicchamber which uses a V connector to connect the antennaDue to the size of the connector compared to the antenna therear radiation patterns were not incorporated in the resultsHowever the similar effects were observed in the simulationresults and most significantly the radiating behavior of theantenna is very similar to simulation results As shown inFigures 19(a) and 19(b) they represent the radiation efficiencyin C band and X band respectively which is 92 and 88
6 Observation and Discussion
From the simulation results we have observed the followingthings
(i) All the structure gives six or more than six resonantfrequencies in C band X band and Ku band
(ii) Gain generated by rectangular and trapezoidal log-arithmic slots array antenna is more than 10 dBcompared to I shape logarithmic slots array antenna
(iii) Isolation between two radiation bands ismuch higherin trapezoidal logarithmic slots array antenna andalso generates low leakage loss in stop band
(iv) Size of entire proposed antennas is compact com-pared to traditional antennas which are proposed forhigh gain applications
(v) Bandwidth produced by all the antennas at resonantfrequencies is more than 100MHz
7 Conclusion
From the design and simulation results it is clear that allthe antennas are compact in size and they are capable togenerate multiband frequencies which are very importantfactors for the proposed design process of antennas Antennasbased on SIW technology have been proposed in this paper
International Journal of Microwave Science and Technology 11
These structures can find many applications in C band and Xband for radar and remote sensingmechanism and are one ofthe major areas in docking satellite where communication isdone in C band while ranging is carried out in X band So thisantenna fulfilled both requirements instead of using two dif-ferent antennas Significant increment of gain parameter hasbeen obtained for introduction of more number and varietyof shapes of slots Compared to identical slots logarithmicslots give higher gain The effect has been extensively studiedunlike any other recent publication in this fieldThe structureis very simple and development of the prototype is easy inpresence of advanced PCB fabrication technology
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] P N Richardson and H Y Lee ldquoDesign and analysis of slottedwaveguide arraysrdquoMicrowave Journal vol 31 pp 109ndash125 1988
[2] S Ravish A Patel V V Dwivedi and H B Pandya ldquoDesigndevelopment and fabrication of post coupled band pass waveg-uide filter at 112 GHz for radiometerrdquo Microwave Journal vol51 2008
[3] A Patel Y Kosta N Chhasatia and K Pandya ldquoMultiple bandwaveguide based microwave resonatorrdquo in Proceedings of the1st International Conference on Advances in Engineering Scienceand Management (ICAESM rsquo12) pp 84ndash87 NagapattinamIndia March 2012
[4] S R Rengarajan ldquoCompound radiating slots in a broad wall ofa rectangular waveguiderdquo IEEE Transactions on Antennas andPropagation vol 37 no 9 pp 1116ndash1123 1989
[5] A Patel and Y P Kosta ldquoMultiple-band waveguide based band-stop filterrdquo International Journal of Applied Electromagnetics andMechanics vol 47 no 2 pp 563ndash581 2015
[6] S Fallahzadeh H Bahrami and M Tayarani ldquoA novel dual-band bandstop waveguide filter using split ring resonatorsrdquoProgress in Electromagnetics Research Letters vol 12 pp 133ndash139 2009
[7] I Ohta Y Yumita K Toda and M Kishihara ldquoCruciformdirectional couplers in H-plane rectangular waveguiderdquo in Pro-ceedings of the Asia-Pacific Microwave Conference (APMC rsquo05)vol 2 December 2005
[8] A Patel Y Kosta N Chhasatia and F Raval ldquoDesign andfabrication of microwave waveguide resonator with improvedcharacteristic responserdquo European Journal of Scientific Researchvol 102 no 2 pp 163ndash174 2013
[9] R S Elliott and L A Kurtz ldquoThe design of small slot arraysrdquoIEEE Transactions on Antennas and Propagation vol 26 no 2pp 214ndash219 1978
[10] R S Elliott ldquoAn improved design procedure for small arrays ofshunt slotsrdquo IEEE Transactions on Antennas and Propagationvol 31 no 1 pp 48ndash53 1983
[11] A F Stevenson ldquoTheory of slots in rectangular wave-guidesrdquoJournal of Applied Physics vol 19 pp 24ndash38 1948
[12] W Coburn M Litz J Miletta N Tesny L Dilks and B KingldquoA slotted-waveguide array for high-power microwave trans-missionrdquo Progress Report for FY 2000 US Army ResearchLaboratory Adelphi Md USA 2001
[13] F Raval Y P Kosta J Makwana and A V Patel ldquoDesign amp im-plementation of reduced size microstrip patch antenna withmetamaterial defected ground planerdquo in Proceedings of the 2ndInternational Conference on Communication and Signal Proc-essing (ICCSP rsquo13) pp 186ndash190 IEEE Melmaruvathur IndiaApril 2013
[14] M Kahrizi T K Sarkar and Z AMaricevic ldquoAnalysis of a wideradiating slot in the ground plane of a microstrip linerdquo IEEETransactions onMicrowaveTheory and Techniques vol 41 no 1pp 29ndash37 1993
[15] J Galejst ldquoAdmittance of a rectangular slot which is backed bya rectangular cavityrdquo IEEE Transactions on Antennas and Prop-agation vol 11 no 2 pp 119ndash126 1963
[16] K-LWongCompact andBroadbandMicrostripAntennas JohnWiley amp Sons New York NY USA 2002
[17] W-S Chen ldquoSingle-feed dual-frequency rectangularmicrostripantenna with square slotrdquo Electronics Letters vol 34 no 3 pp231ndash232 1998
[18] D Busuioc M Shahabadi A Borji G Shaker and S Safavi-Naeini ldquoSubstrate integrated waveguide antenna feedmdashdesignmethodology and validationrdquo in Proceedings of the IEEE Anten-nas and Propagation Society International Symposium (AP-Srsquo07) pp 2666ndash2669 Honolulu Hawaii USA June 2007
[19] H Kumar R Jadhav and S Ranade ldquoA review on substrateintegrated waveguide and its microstrip interconnectrdquo Journalof Electronics and Communication Engineering vol 3 no 5 pp36ndash40 2012
[20] M Bozzi F XuDDeslandes andKWu ldquoModeling and designconsiderations for substrate integrated waveguide circuits andcomponentsrdquo in Proceedings of the 8th International Conferenceon Telecommunications in Modern Satellite Cable and Broad-casting Services (TELSIKS rsquo07) pp P-7ndashP-16 IEEE Nis SerbiaSeptember 2007
[21] S Moitra A Mukhopadhyay and A Bhattacharjee ldquoKu-bandsubstrate integrated waveguide (SIW) slot array antenna fornext generation networksrdquo Global Journal of Computer Scienceand Technology E Network Web amp Security vol 13 no 5 pp11ndash16 2013
[22] A J Farrall and P R Young ldquoIntegrated waveguide slot anten-nasrdquo Electronics Letters vol 40 no 16 pp 974ndash975 2004
[23] D PozarMicrowave Engineering JohnWiley amp Sons HobokenNJ USA 3rd edition 2005
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
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Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
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International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
2 International Journal of Microwave Science and Technology
be implemented using microstrip technology using a flexiblesubstrate or multifaceted surfaces [15]
This mature technology leads to not only low-costdesigns but also the possibility to easily integrate themwith common electronic components However these planardesigns are by nature not fully shielded and thus subject toradiation cross-talk and packaging problems [16] It has alsocomplex feed networks such as probes feeding patch ele-ments Strip line can be used to eliminate the radiation losseshowever cross coupling problems are encountered in the feednetwork with strip line structure These drawbacks added tothe potentially high conductor losses make this technologynot feasible to implement high frequency complex structuressuch as large feeding networks [17] It is then obvious that alarge performance gap exists between components based onmetallic waveguides and the ones based on PCBs
A very promising candidate to fill this gap and to providewidespread commercial solutions is the SIW technologyor more in general the Substrate Integrated Circuit (SIC)architecture [18] This technology allows building high per-formance low cost and reliable waveguide-like componentsusing planar processing techniques such as the PCB or theLow-Temperature Cofired Ceramic (LTCC) [19] It has alsounique features such as compact size in comparison withwaveguide antennas and also simpler structure in compari-son with reflector antennas [1]
On the basis of the above two SIW slot array antennashave been proposed with high gain and ultrawide bandwidthspecifically forC band X band andKuband applicationsTheproposed structures contain three different shapes of slotslike rectangle trapezoidal and I shape and its size variesaccording to logarithmvalueAll the structures generate quitebetter results and respond to resonant frequencies accordingto their size One of the unique features of them is that theygenerate sharp radiation pattern and isolation between bandsis much more high Due to these advantages the slotted SIWantennas are good candidates for the conformal array appli-cations especially when SIW is implemented using a flexiblesubstrate There is a limited study in the literature on theconformal array applications with slotted waveguide arrays
With the aim of the above the structure of paper isas follows Section 2 describes the theory of basic SIW andbased on it is the design of slotted linear arrays of antennaThen Section 3 shows the design and calculation of variousproposed antennas and their simulation results are shown inSection 4 Section 5 contains comparison of all the proposedantennas and discussion of results Finally paper is endedwith conclusion
2 SIW Antenna Design
SIW is described as two conducting layers are connected bycylindrical vias row at both sides which is shown in Figure 1[20] In Figure 1 119889 is the diameter of vias 119908 is the equivalentwidth of SIW 119901 is the spacing between two vias and ℎ is thethickness of substrate Structure of SIW contains low costhigh 119876-factor low radiation and high density integrationwhich makes it preferable
W
d
h
P
Dielectricsubstrate
Unit cell
Metal post
Top metallayer
Figure 1 Basic structure of SIW
The cutoff frequency of SIW is defined as 119891119888= 1198882119886
where 119886 is width of waveguide it can change by varying thewidth in conciliation of degrading the overall characteristicsof its components
As we know that the current in the walls of the waveguidemust be comparative to the difference in the electric fieldbetween two points (so the selection of slot in SIW is veryimportant) [21]Therefore tomake a slot in the correct centerof the broad wall of the waveguide will not radiate at all sincethe electric field is not asymmetrical around the center ofthe guide and thus is indistinguishable at both edges of theslot If the position of slot is moved from the centerline thedifference in field concentration between the rims of the slotis larger so that more current is interrupted andmore energyis coupled to the slot that ultimately increases radiated powerIn other sides of thewaveguide the field strength is veryweaksince the sidewalls are short circuited for the electric fieldThe produced current must also be small longitudinal slotswhich are far from the center or created in the sidewall willnot radiate significantly
In this paper we keep the distance between slots as 1205821198922
such that the slots will be fed in the same phase (spacingbetween the slots at 120582
1198922 intervals in the waveguide is an
equivalent electrical spacing of 180∘ Therefore each slot isexactly out of phase with its neighbors so their radiationcancelled each otherOn the other side slots on opposite sidesof the center axis of the guide are out of phase (180∘) so wecan swap the slot displacement around the center axis andhave a total phase difference of 360∘ between slots puttingthem back in phase) and the beam will not be inclined [22]For the position of the last slot the center of slot is kept atguided quarter wavelength away from the closed end of thewaveguide As we know that a short circuited quarter wave-length stub of transmission line works as an open-circuitthe closed end does not impact on the impedance Anotherreason to keep the closed end is space 3120582
1198924 for mechanical
fabrication the extra half-wavelength is crystal clear
3 SIW Slots Array Antenna Parameters
TheSIW slots array antenna is shown in Figure 2Here primeimportant parameters in the design are distance and diameterof posts which controlled the flow of electric field Slots are
International Journal of Microwave Science and Technology 3
a
p d
2l
l 3l4lwat
lt lw
a998400
Figure 2 Schematic of proposed antenna
30mm
15mm 553mm
Figure 3 Microstrip to SIW transition
2136mm1424mm3376mm
1702mm
9mm 10mm30mm
0508mm
Figure 4 Side and top view of 1st proposed logarithmic rectangularslots array antenna
printed on a 0508mm thick Roger RT duroid 5880 substrate(the relative dielectric constant is 22) with the size of 119882 times119871 = (3376 times 1702)mm The selection of feed is also veryimportant and here we have selected feeding using taperedslot which is shown in Figure 3 that provide transition frommicrostrip to SIW [23] A tapered microstrip line has thefollowing parameters the width of the feed line 119886
119905= 15mm
119908 = 553mm and the length of feed line 119897119905= 30mm
(calculation of all the parameters are shown below)The finiteground plane has an area of119882times119867 = (3376 times 1702)mm
Parameters Calculation [21](1) For designing SIW based antenna define first sub-
strate dimensions which are given by 119886 times 119887 for that119886
1015840 and 119886must be known as shown below (1198861015840 inverselypropositional to cutoff frequency)
119886
1015840
=
119888
2119891
119888radic120576
119903
(1)
(2) Now obtain center-to-center distance with the help of119886
1015840 as
119886 = 119886
1015840
+
119889
2
095119901
(2)
minus3500
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
625 750 875 1000 1125 1250 1375 1500
Freq (GHz)
m1
m2
m3m4
m5
m6
Curve info
Setup1 sweep
Name X Y
m1
m2
m3
m4
m5
m6
70500
102000
108500
119000
128000
146000
minus314424
minus124807
minus210062
minus238238
minus126106
minus263216
S11 (dB)
S 11
(dB)
Figure 5 11987811
of 1st proposed logarithmic rectangular slots arrayantenna
625 750 875 1000 1125 1250 1375 1500
Freq (GHz)
000
500
1000
1500
2000
2500
3000
3500
VSW
R(1
)
Curve infoVSWR(1)
Setup1 sweep
m1 m2 m3 m4 m5 m6
Name X Y
m1
m2
m3
m4
m5
m6
70500
102000
108500
119000
128000
146000
10550
16235
11955
11376
16114
11015
Figure 6 VSWR of 1st proposed logarithmic rectangular slots arrayantenna
(3) To select the diameter of post and also distancebetween two posts we have to consider the followingcondition which minimizes the losses [1]
119901 le 2119889
005 lt (
119901
120582
119888
) lt 025
120582
119892
5
lt 119889
(3)
where 120582119892is given by
120582
119892=
120582
119888
radic
120576
119903
(4)
Here 119901 is the center-to-center distance between twoposts 119889 is the diameter of the post 120582
119892is guided wave-
length 120582119888is cutoffwavelength 120576
119903is relative permittiv-
ity of dielectric medium(4) To apply tapper feed at antenna first find the tapper
width by using traditional microstrip calculationwhich is denoted by (119908
1) and after that feeding width
at dielectric side
4 International Journal of Microwave Science and Technology
2008001400
90
60
300
150
120
200
400
600800
90
60
300
150
120
160320480640
90
60
300
150
120
Antenna gain plot for 108GHz
Antenna gain plot for 119GHz
Antenna gain plot for 705GHz
Radiation pattern for solution frequency 119GHz
Radiation pattern for solution frequency 108GHz
Radiation pattern for solution frequency 705GHz
minus400
minus30
minus60
minus90
minus120
minus150minus180
minus30
minus60
minus90
minus120
minus150
minus180
minus30
minus60
minus90
minus120
minus150minus180
Curve inforETotal (dB)
Setup1 LastAdaptiveFreq = 705GHz Theta = 90degldquo ldquordquo rdquo
rETotalCurve info
Setup1 LastAdaptiveFreq = 1085GHz Theta = 90degldquo ldquordquo rdquo
Curve info
Setup1 LastAdaptiverETotal
Freq = 119GHz Theta = 90degldquo ldquordquo rdquo
71077e + 00050667e + 00030257e + 00098467e minus 001minus10563e + 000
minus51383e + 000minus71793e + 000minus92203e + 000minus11261e + 001minus13302e + 001minus15343e + 001minus17384e + 001minus19425e + 001minus21466e + 001minus23507e + 001minus25548e + 001
GainTotal (dB)
GainTotal (dB)
GainTotal (dB)
X
Y
Z
X
Y
Z
X
Y
Z
75069e + 00057476e + 00039883e + 00022290e + 00046965e minus 001minus12896e + 000minus30489e + 000minus48082e + 000minus65675e + 000minus83268e + 000minus10086e + 001minus11845e + 001minus13605e + 001minus15364e + 001minus17123e + 001minus18883e + 001minus20642e + 001
10685e + 001
40077e + 000
minus26697e + 000
minus93470e + 000
minus16024e + 001
minus22702e + 001
minus29379e + 001
minus30973e + 000
Figure 7 Continued
International Journal of Microwave Science and Technology 5
200
400600800
90
60
300
150
120
Antenna gain plot for 146GHz Radiation pattern for solution frequency 146GHz
minus30
minus60
minus90
minus120
minus150minus180
Curve info
Setup1 LastAdaptiverETotal
Freq = 146GHz Theta = 90degldquo ldquordquo rdquo
X
Y
Z
69798e + 00048590e + 00027382e + 00061746e minus 001minus15033e + 000minus36241e + 000minus57449e + 000minus78657e + 000minus99865e + 000minus12107e + 001minus14228e + 001minus16349e + 001minus18470e + 001minus20590e + 001minus22711e + 001minus24832e + 001minus26953e + 001
GainTotal (dB)
Figure 7 Gain plots and radiation patterns at different resonant frequencies
The width of tapper at feed side is 04 times the open-ing of patch antenna
119886
119905= 04 (119886 minus 119889) (5)
The width of tapper at antenna side is
119908 =
119888
2119891radic(120576
119903+ 1) 2
(6)
Finally length of tapper for impedance match is given by
119897
119905=
119899 lowast 120582
119892
4
where 119899 = 1 2 3 (7)
It is already derived that the gain and beamwidth formula forthe slots have equal distance end to end and spacing along thewaveguide A simple procedure to calculate the gain of a slotantenna is on array of dipoles As we double the dipole slotsthey increase the double gain So for 16 slots it is possible toget gain of 12 dB Each time we double the number of dipoleswe double the gain or add 3 dB Thus a 16-slot array wouldhave a gain of about 12 dB Gain can be calculated from theequation 119866 = 10 log(119873) dB for119873 total slots
Now include the effect of gain with spacing of slot betterto be described as
Gain = 10 log119873 lowast slotspacing120582
0
dB (8)
Calculated gain is always equal to average gain nowbeamwidth is given by
Beamwidth = 507120582
0
(1198732) lowast slotspacingDegree (9)
Table 1 Specification of the proposed structure
Parameters ValueCenter frequency 7GHzReturn loss gtminus10 dBVSWR 1Gain gt5 dBDielectric constant (RT duroid) 22
4 Design of Proposed Structures
Here we have considered the design of proposed structurebased on the specification given in Table 1 These specifi-cations are considered based on the satellite and RADARapplications in which we are targeting C X and Ku bandfrequencies The C band X band and Ku Band defined byan IEEE standard for radio waves and radar engineering withfrequencies that range from 40 to 80GHz 80 to 120GHzand 120 to 180GHz respectively Frequency range of 37 to42GHz is used for the satellite downlink communicationin C band and the band of frequencies from 5925GHz to6425GHz for their uplinks The X band is used for shortrange tracking missile guidance marine radar and airborneintercept It is used especially for radar communicationranges roughly from 829GHz to 114 GHz The Ku band isused for high resolution mapping and satellite altimetry Kuband especially is used for tracking the satellite within theranges roughly from 1287GHz to 1443GHz
From the above applications the proposed structuredesign is targeted at center frequency of 7GHz Physicaldimensions of the first proposed structure are calculated bythe above formula and summarized in Table 2 The wire linestructure of proposed antenna is shown in Figure 3
6 International Journal of Microwave Science and Technology
625 825 1025 1225 1425
minus35
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo63mmrdquob1 = ldquo1856mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1256mmrdquoa1f = ldquo425mmrdquoS11 (dB)
S11 (dB)
S11 (dB)
(a)
625 825 1025 1225 1425
minus45
minus40
minus35
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo73mmrdquob1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo53mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquoS11 (dB)
S11 (dB)
S11 (dB)
(b)
625 825 1025 1225 1425
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo63mmrdquob1 = ldquo1556mmrdquoa1f = ldquo525mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo325mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo225mmrdquoS11 (dB) S11 (dB)
S11 (dB)
(c)
Figure 8 (a) 11987811of logarithmic rectangular slots array antenna with respect to variations in 1st slot position (b) 119878
11of logarithmic rectangular
slots array antennawith respect to variations in 1st slot position (c) 11987811of logarithmic rectangular slots array antennawith respect to variations
in width of 1st slot
International Journal of Microwave Science and Technology 7
Table 2 Calculated parameters
Parameter 119891
119888119886
1015840
119863 119875 119886
119904120576
119903120582
119888120582
119892119908 119886
119905119897
119908119897
119905
Value 71 GHz 142mm 9mm 10mm 2276mm 22 4225mm 2848mm 5504mm 15mm 170mm 30mm
Table 3 Summaries of simulated parameters
Resonant frequency Gain in dB Bandwidth in MHz VSWR Peak return loss in dB705GHz 1085 100 105 minus31431085GHz 75 200 119 minus2100119 GHz 71 250 113 minus2371146GHz 69 400 1097 minus2664
As shown in Figure 4 it contains six rectangular slotsarray whose longitudinal length is varied according to log-arithmic manner We are keeping center-to-center distancebetween two slots as 1424mm (120582
1198922) and center of last slot
to broadside wall as 2136mmThe structure has been simulated using HFSS (High Fre-
quency Structure Simulator) and it generates return lossshown in Figure 5 As shown in Figure 5 the structure gen-erates six resonant frequencies one in C band (705GHz)three in X band (102 1055 and 115 GHz) and two inKu band (128 and 146GHz) respectively These results aretotally expected since the proposed antenna is composedof different resonant slot lengths providing the multibandperformance At all the resonant frequencies VSWR is alsogood which is shown in Figure 6 One of the extraordinaryperformances generated by this structure is shown in Figure 7which represents the gain value that is more than 10 dBin single layer and single array combination compared toother traditional antennas having multilayer and 2 to 3arrays for achieving higher gain Various gain and radiationpatterns of the proposed logarithmic slots array of antennafor different resonant frequencies are shown in Figure 6 Allthe simulation results are summarized in Table 3
It is possible to tune the frequency by changing the geo-metrical position with respect to wave propagation directionand physical dimensions of the slots All these methodsultimately changed the value of reactance of resonators andcoupling of the EM field Here we have demonstrated threepossible methods to tune the response (i) pose of slot (ii)length of slot (iii) width of slot For demonstration andanalysis purpose onlywe applied the above tuningmethods tothe first slot These methods can also be applicable for otherremaining slots Figure 8(a) demonstrates simulation resultof reflection coefficient obtained by changing the positionof first slot which was kept at 120582
1198922 distance with respect
to second slot in longitude direction It shows that whenwe move the slot position in positive longitude direction itimproves the value of return loss and increment in oppositedirection it reduces the value of return loss Figure 8(b)shows the simulation result with increasing the length of thefirst slot It decreases the values of inductance and increasesthe capacitance value Variation in length gave minor effecton a reflection coefficient value Similarly Figure 8(c) is theresult of reflection coefficient with the change in width of
1424mm4mm3376mm
1702mm
0508mm
2136mm
9mm 10mm30mm
Figure 9 2nd proposed structure contains I shape logarithmic slotsarray antenna
m3
m4
m5
m6
m7m8m9
m2 m10
m1
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
700 800 900 1000 1100 1200 1300 1400 1500600
Curve info
Setup1 sweep
Freq (GHz)
Name X Y
m1 77080m2 81210m3 84170m4 87660m5 92910m6 102010m7 104890m8 109930m9 118430m10 137490 minus124121
minus156759minus138911minus147592minus226325minus274168minus103236minus241340minus124315minus180066
S11 (dB)
S 11
(dB)
Figure 10 11987811plot for I shaped logarithmic slots array antenna
the first slot that tunes resonant frequency effectively and alsoproduces very sharp bandwidth
In the second proposed structure instead of takingrectangular shape slots longitudinal I shape is selected whichis shown in Figure 9 Spacing between two slots and centerdistance of last slots from the end boadsie wall are the same as1st proposed design In first I shape slot vertical height of theslot is 4mm and length of slot is 10mm which progressivelyincreases for other slots according to logarthmic nature
This structure is also simulated by using HFSS and itsreturn loss is shwon in Figure 10 This structure radiates atsix resonant frequencies one in C band (77 GHz) three inX band (812 841 876 929 102 1048 1099 1145 and
8 International Journal of Microwave Science and Technology
Y
Z
53483e + 00033392e + 00013301e + 000minus67903e minus 001minus26881e + 000minus46972e + 000minus67063e + 000minus87154e + 000minus10725e + 001minus12734e + 001minus14743e + 001minus16752e + 001minus18761e + 001minus20770e + 001minus22779e + 001minus24788e + 001minus26797e + 001
GainTotal (dB)
(a)
080
160
240
320
90
60
300
150
120
Curve inforETotal
Setup1 LastAdaptiveFreq = 71GHz Theta = 90degldquo ldquordquo rdquo
minus30
minus60
minus90
minus120
minus150minus180
(b)
Figure 11 (a) Gain plot and (b) radiation pattern for I shape logarithmic slots array antenna
1424mm 3376mm
1702mm
0508mm
9mm 10mm30mm
15mm 21mm
Figure 12 3rd proposed structure contains trapezoidal logarithmic slots array antenna
m2
m3
m4m5 m6
m7
m8m1
Curve info
Setup1 sweep
700 800 900 1000 1100 1200 1300 1400 1500600Freq (GHz)
minus3500
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
Name X Y
m1 67300m2 78400m3 103800m4 110700m5 114300m6 121400m7 128100m8 143600 minus183495
minus300236
minus181027minus163299
minus202328
minus270798
minus154970minus159939
S11 (dB)
S 11
(dB)
Figure 13 11987811plot for trapezoidal logarithmic slots array antenna
119 GHz) and two in Ku band (1395 and 145 GHz)The gainplot and radiation pattern for 67GHz frequency are shownin Figures 11(a) and 11(b) which shows that it generates gainof 5 dB which is half compared to first proposed structure
Third proposed structure contains trapezoidal logarith-mic slots array as shown in Figure 12 Distances of all the slots
m1 m2 m3 m4 m5 m6 m7 m8
700 800 900 1000 1100 1200 1300 1400 1500600Freq (GHz)
000500
100015002000250030003500
VSW
R(1)
Curve infoVSWR(1)
Setup1 sweep
Name X Ym1 67200 13759m2 78400 14037m3 103800 10926m4 110700 12157m5 114300 13601m6 121400 12842m7 128000 10823m8 143700 12861
Figure 14 VSWR of 3rd proposed trapezoidal logarithmic slotsarray antenna
are the same as 1st proposed design Simulated result of theproposed structure is shown in Figure 13 which shows higherreturn loss occurring at eight different frequencies two in Cband (67 and 754GHz) four in X band (1025 11 1143 and
International Journal of Microwave Science and Technology 9
10300e + 001
79774e + 000
33329e + 00056551e + 000
10107e + 000minus13115e + 000minus36337e + 000minus59560e + 000minus82782e + 000minus10600e + 001minus12923e + 001minus15245e + 001minus17567e + 001minus19889e + 001minus22211e + 001
minus26856e + 001
minus24534e + 001
GainTotal (dB)
Y
Z
(a)
Curve inforETotal
Setup1 LastAdaptiveFreq = 71GHz Theta = 90degldquo ldquordquo rdquo
minus30
minus90
minus120
minus150
minus180
minus60
200
400
600
800
90
60
300
150
120
(b)
Figure 15 (a) Gain plot and (b) radiation pattern for trapezoidal logarithmic slots array antenna
Figure 16 Fabricated model of logarithmic rectangular slots arrayantenna
5 10 15
minus30
minus25
minus20
minus15
minus10
minus5
0
Simulated S11 (dB)Measured S11 (dB)
Figure 17 11987811of logarithmic rectangular slots array antenna
1214GHz) and Ku band (1281 and 1436GHz) Its VSWR isshown in Figure 14Gain plot and radiation pattern are shownin Figures 15(a) and 15(b) respectively It gives more than10 dB gain at 67 GHz frequency
Simulated gainMeasured gain
00 30 60 90 120 150 180 210 240 270 300 360330
1
2
3
4
5
6
7
8
9
10
Figure 18 Gain of logarithmic rectangular slots array antenna
5 Measured Results
Logarithmic rectangular slots array antenna has been fabri-cated on Rogers RT Duroid 5880 high frequency substratewith a thickness of 0787mm relative permittivity of 22 andrelative permeability of 1 and loss tangent of 00009 The topside of the antenna has logarithmic slots and the other side isground planeThe photograph of fabricated antenna is shownin Figure 16
The antenna 11987811parameter and gain are measured using
the Vector Network Analyzer MVNA-8-350 with probe sta-tion The simulated and measured 119878
11parameter for antenna
is shown in Figure 17 A slight difference is observed between
10 International Journal of Microwave Science and Technology
Radiation efficiency
100
095
090
085
HFSSCurve info
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Radiation efficiency
Radiation efficiency
Setup1 LastAdaptiveFreq = 71GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Freq = 71GHz Theta = 10degldquo ldquordquo rdquo
Freq = 71GHz Theta = 20degldquo ldquordquo rdquo
Freq = 71GHz Theta = 50degldquo ldquordquo rdquo
Freq = 71GHz Theta = 40degldquo ldquordquo rdquo
Freq = 71GHz Theta = 60degldquo ldquordquo rdquo
Freq = 71GHz Theta = 30degldquo ldquordquo rdquo
(a)
Radiation efficiency
HFSS design2Curve info
096
092
088
084
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 10degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 20degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 50degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 40degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 60degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 30degldquo ldquordquo rdquo
(b)
Figure 19 Radiation efficiency of logarithmic rectangular slots array antenna in (a) C band and (b) X band
the measured value and simulated value The differencebetween the measured and simulated 119878
11of the antenna is
caused by the microstrip to SIW transitionThe simulated and measured gain of the antenna are
shown in Figure 18Themaximummeasured gain is also veryclose to 10 dB at 7GHz for the antenna which is max Themeasured result shows that the bandwidth of the antennacovers over 300MHz while the gain of the antenna is keptalmost constantwithin such awide bandwidth of the antennaSimulation results specify that metallic and dielectric lossesdo not have a substantial effect on the bandwidth andmatching condition of the antenna while they decrease themeasured gain of antenna by 05 dB The apparent differencebetween the simulation and measured gains might be dueto the calibration linked tolerance range of the antennareference in anechoic chamber
The radiation pattern of the antenna at resonant fre-quency is shown in Figure 18 The radiation pattern mea-surement is carried out in a conventional far field anechoicchamber which uses a V connector to connect the antennaDue to the size of the connector compared to the antenna therear radiation patterns were not incorporated in the resultsHowever the similar effects were observed in the simulationresults and most significantly the radiating behavior of theantenna is very similar to simulation results As shown inFigures 19(a) and 19(b) they represent the radiation efficiencyin C band and X band respectively which is 92 and 88
6 Observation and Discussion
From the simulation results we have observed the followingthings
(i) All the structure gives six or more than six resonantfrequencies in C band X band and Ku band
(ii) Gain generated by rectangular and trapezoidal log-arithmic slots array antenna is more than 10 dBcompared to I shape logarithmic slots array antenna
(iii) Isolation between two radiation bands ismuch higherin trapezoidal logarithmic slots array antenna andalso generates low leakage loss in stop band
(iv) Size of entire proposed antennas is compact com-pared to traditional antennas which are proposed forhigh gain applications
(v) Bandwidth produced by all the antennas at resonantfrequencies is more than 100MHz
7 Conclusion
From the design and simulation results it is clear that allthe antennas are compact in size and they are capable togenerate multiband frequencies which are very importantfactors for the proposed design process of antennas Antennasbased on SIW technology have been proposed in this paper
International Journal of Microwave Science and Technology 11
These structures can find many applications in C band and Xband for radar and remote sensingmechanism and are one ofthe major areas in docking satellite where communication isdone in C band while ranging is carried out in X band So thisantenna fulfilled both requirements instead of using two dif-ferent antennas Significant increment of gain parameter hasbeen obtained for introduction of more number and varietyof shapes of slots Compared to identical slots logarithmicslots give higher gain The effect has been extensively studiedunlike any other recent publication in this fieldThe structureis very simple and development of the prototype is easy inpresence of advanced PCB fabrication technology
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] P N Richardson and H Y Lee ldquoDesign and analysis of slottedwaveguide arraysrdquoMicrowave Journal vol 31 pp 109ndash125 1988
[2] S Ravish A Patel V V Dwivedi and H B Pandya ldquoDesigndevelopment and fabrication of post coupled band pass waveg-uide filter at 112 GHz for radiometerrdquo Microwave Journal vol51 2008
[3] A Patel Y Kosta N Chhasatia and K Pandya ldquoMultiple bandwaveguide based microwave resonatorrdquo in Proceedings of the1st International Conference on Advances in Engineering Scienceand Management (ICAESM rsquo12) pp 84ndash87 NagapattinamIndia March 2012
[4] S R Rengarajan ldquoCompound radiating slots in a broad wall ofa rectangular waveguiderdquo IEEE Transactions on Antennas andPropagation vol 37 no 9 pp 1116ndash1123 1989
[5] A Patel and Y P Kosta ldquoMultiple-band waveguide based band-stop filterrdquo International Journal of Applied Electromagnetics andMechanics vol 47 no 2 pp 563ndash581 2015
[6] S Fallahzadeh H Bahrami and M Tayarani ldquoA novel dual-band bandstop waveguide filter using split ring resonatorsrdquoProgress in Electromagnetics Research Letters vol 12 pp 133ndash139 2009
[7] I Ohta Y Yumita K Toda and M Kishihara ldquoCruciformdirectional couplers in H-plane rectangular waveguiderdquo in Pro-ceedings of the Asia-Pacific Microwave Conference (APMC rsquo05)vol 2 December 2005
[8] A Patel Y Kosta N Chhasatia and F Raval ldquoDesign andfabrication of microwave waveguide resonator with improvedcharacteristic responserdquo European Journal of Scientific Researchvol 102 no 2 pp 163ndash174 2013
[9] R S Elliott and L A Kurtz ldquoThe design of small slot arraysrdquoIEEE Transactions on Antennas and Propagation vol 26 no 2pp 214ndash219 1978
[10] R S Elliott ldquoAn improved design procedure for small arrays ofshunt slotsrdquo IEEE Transactions on Antennas and Propagationvol 31 no 1 pp 48ndash53 1983
[11] A F Stevenson ldquoTheory of slots in rectangular wave-guidesrdquoJournal of Applied Physics vol 19 pp 24ndash38 1948
[12] W Coburn M Litz J Miletta N Tesny L Dilks and B KingldquoA slotted-waveguide array for high-power microwave trans-missionrdquo Progress Report for FY 2000 US Army ResearchLaboratory Adelphi Md USA 2001
[13] F Raval Y P Kosta J Makwana and A V Patel ldquoDesign amp im-plementation of reduced size microstrip patch antenna withmetamaterial defected ground planerdquo in Proceedings of the 2ndInternational Conference on Communication and Signal Proc-essing (ICCSP rsquo13) pp 186ndash190 IEEE Melmaruvathur IndiaApril 2013
[14] M Kahrizi T K Sarkar and Z AMaricevic ldquoAnalysis of a wideradiating slot in the ground plane of a microstrip linerdquo IEEETransactions onMicrowaveTheory and Techniques vol 41 no 1pp 29ndash37 1993
[15] J Galejst ldquoAdmittance of a rectangular slot which is backed bya rectangular cavityrdquo IEEE Transactions on Antennas and Prop-agation vol 11 no 2 pp 119ndash126 1963
[16] K-LWongCompact andBroadbandMicrostripAntennas JohnWiley amp Sons New York NY USA 2002
[17] W-S Chen ldquoSingle-feed dual-frequency rectangularmicrostripantenna with square slotrdquo Electronics Letters vol 34 no 3 pp231ndash232 1998
[18] D Busuioc M Shahabadi A Borji G Shaker and S Safavi-Naeini ldquoSubstrate integrated waveguide antenna feedmdashdesignmethodology and validationrdquo in Proceedings of the IEEE Anten-nas and Propagation Society International Symposium (AP-Srsquo07) pp 2666ndash2669 Honolulu Hawaii USA June 2007
[19] H Kumar R Jadhav and S Ranade ldquoA review on substrateintegrated waveguide and its microstrip interconnectrdquo Journalof Electronics and Communication Engineering vol 3 no 5 pp36ndash40 2012
[20] M Bozzi F XuDDeslandes andKWu ldquoModeling and designconsiderations for substrate integrated waveguide circuits andcomponentsrdquo in Proceedings of the 8th International Conferenceon Telecommunications in Modern Satellite Cable and Broad-casting Services (TELSIKS rsquo07) pp P-7ndashP-16 IEEE Nis SerbiaSeptember 2007
[21] S Moitra A Mukhopadhyay and A Bhattacharjee ldquoKu-bandsubstrate integrated waveguide (SIW) slot array antenna fornext generation networksrdquo Global Journal of Computer Scienceand Technology E Network Web amp Security vol 13 no 5 pp11ndash16 2013
[22] A J Farrall and P R Young ldquoIntegrated waveguide slot anten-nasrdquo Electronics Letters vol 40 no 16 pp 974ndash975 2004
[23] D PozarMicrowave Engineering JohnWiley amp Sons HobokenNJ USA 3rd edition 2005
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
International Journal of Microwave Science and Technology 3
a
p d
2l
l 3l4lwat
lt lw
a998400
Figure 2 Schematic of proposed antenna
30mm
15mm 553mm
Figure 3 Microstrip to SIW transition
2136mm1424mm3376mm
1702mm
9mm 10mm30mm
0508mm
Figure 4 Side and top view of 1st proposed logarithmic rectangularslots array antenna
printed on a 0508mm thick Roger RT duroid 5880 substrate(the relative dielectric constant is 22) with the size of 119882 times119871 = (3376 times 1702)mm The selection of feed is also veryimportant and here we have selected feeding using taperedslot which is shown in Figure 3 that provide transition frommicrostrip to SIW [23] A tapered microstrip line has thefollowing parameters the width of the feed line 119886
119905= 15mm
119908 = 553mm and the length of feed line 119897119905= 30mm
(calculation of all the parameters are shown below)The finiteground plane has an area of119882times119867 = (3376 times 1702)mm
Parameters Calculation [21](1) For designing SIW based antenna define first sub-
strate dimensions which are given by 119886 times 119887 for that119886
1015840 and 119886must be known as shown below (1198861015840 inverselypropositional to cutoff frequency)
119886
1015840
=
119888
2119891
119888radic120576
119903
(1)
(2) Now obtain center-to-center distance with the help of119886
1015840 as
119886 = 119886
1015840
+
119889
2
095119901
(2)
minus3500
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
625 750 875 1000 1125 1250 1375 1500
Freq (GHz)
m1
m2
m3m4
m5
m6
Curve info
Setup1 sweep
Name X Y
m1
m2
m3
m4
m5
m6
70500
102000
108500
119000
128000
146000
minus314424
minus124807
minus210062
minus238238
minus126106
minus263216
S11 (dB)
S 11
(dB)
Figure 5 11987811
of 1st proposed logarithmic rectangular slots arrayantenna
625 750 875 1000 1125 1250 1375 1500
Freq (GHz)
000
500
1000
1500
2000
2500
3000
3500
VSW
R(1
)
Curve infoVSWR(1)
Setup1 sweep
m1 m2 m3 m4 m5 m6
Name X Y
m1
m2
m3
m4
m5
m6
70500
102000
108500
119000
128000
146000
10550
16235
11955
11376
16114
11015
Figure 6 VSWR of 1st proposed logarithmic rectangular slots arrayantenna
(3) To select the diameter of post and also distancebetween two posts we have to consider the followingcondition which minimizes the losses [1]
119901 le 2119889
005 lt (
119901
120582
119888
) lt 025
120582
119892
5
lt 119889
(3)
where 120582119892is given by
120582
119892=
120582
119888
radic
120576
119903
(4)
Here 119901 is the center-to-center distance between twoposts 119889 is the diameter of the post 120582
119892is guided wave-
length 120582119888is cutoffwavelength 120576
119903is relative permittiv-
ity of dielectric medium(4) To apply tapper feed at antenna first find the tapper
width by using traditional microstrip calculationwhich is denoted by (119908
1) and after that feeding width
at dielectric side
4 International Journal of Microwave Science and Technology
2008001400
90
60
300
150
120
200
400
600800
90
60
300
150
120
160320480640
90
60
300
150
120
Antenna gain plot for 108GHz
Antenna gain plot for 119GHz
Antenna gain plot for 705GHz
Radiation pattern for solution frequency 119GHz
Radiation pattern for solution frequency 108GHz
Radiation pattern for solution frequency 705GHz
minus400
minus30
minus60
minus90
minus120
minus150minus180
minus30
minus60
minus90
minus120
minus150
minus180
minus30
minus60
minus90
minus120
minus150minus180
Curve inforETotal (dB)
Setup1 LastAdaptiveFreq = 705GHz Theta = 90degldquo ldquordquo rdquo
rETotalCurve info
Setup1 LastAdaptiveFreq = 1085GHz Theta = 90degldquo ldquordquo rdquo
Curve info
Setup1 LastAdaptiverETotal
Freq = 119GHz Theta = 90degldquo ldquordquo rdquo
71077e + 00050667e + 00030257e + 00098467e minus 001minus10563e + 000
minus51383e + 000minus71793e + 000minus92203e + 000minus11261e + 001minus13302e + 001minus15343e + 001minus17384e + 001minus19425e + 001minus21466e + 001minus23507e + 001minus25548e + 001
GainTotal (dB)
GainTotal (dB)
GainTotal (dB)
X
Y
Z
X
Y
Z
X
Y
Z
75069e + 00057476e + 00039883e + 00022290e + 00046965e minus 001minus12896e + 000minus30489e + 000minus48082e + 000minus65675e + 000minus83268e + 000minus10086e + 001minus11845e + 001minus13605e + 001minus15364e + 001minus17123e + 001minus18883e + 001minus20642e + 001
10685e + 001
40077e + 000
minus26697e + 000
minus93470e + 000
minus16024e + 001
minus22702e + 001
minus29379e + 001
minus30973e + 000
Figure 7 Continued
International Journal of Microwave Science and Technology 5
200
400600800
90
60
300
150
120
Antenna gain plot for 146GHz Radiation pattern for solution frequency 146GHz
minus30
minus60
minus90
minus120
minus150minus180
Curve info
Setup1 LastAdaptiverETotal
Freq = 146GHz Theta = 90degldquo ldquordquo rdquo
X
Y
Z
69798e + 00048590e + 00027382e + 00061746e minus 001minus15033e + 000minus36241e + 000minus57449e + 000minus78657e + 000minus99865e + 000minus12107e + 001minus14228e + 001minus16349e + 001minus18470e + 001minus20590e + 001minus22711e + 001minus24832e + 001minus26953e + 001
GainTotal (dB)
Figure 7 Gain plots and radiation patterns at different resonant frequencies
The width of tapper at feed side is 04 times the open-ing of patch antenna
119886
119905= 04 (119886 minus 119889) (5)
The width of tapper at antenna side is
119908 =
119888
2119891radic(120576
119903+ 1) 2
(6)
Finally length of tapper for impedance match is given by
119897
119905=
119899 lowast 120582
119892
4
where 119899 = 1 2 3 (7)
It is already derived that the gain and beamwidth formula forthe slots have equal distance end to end and spacing along thewaveguide A simple procedure to calculate the gain of a slotantenna is on array of dipoles As we double the dipole slotsthey increase the double gain So for 16 slots it is possible toget gain of 12 dB Each time we double the number of dipoleswe double the gain or add 3 dB Thus a 16-slot array wouldhave a gain of about 12 dB Gain can be calculated from theequation 119866 = 10 log(119873) dB for119873 total slots
Now include the effect of gain with spacing of slot betterto be described as
Gain = 10 log119873 lowast slotspacing120582
0
dB (8)
Calculated gain is always equal to average gain nowbeamwidth is given by
Beamwidth = 507120582
0
(1198732) lowast slotspacingDegree (9)
Table 1 Specification of the proposed structure
Parameters ValueCenter frequency 7GHzReturn loss gtminus10 dBVSWR 1Gain gt5 dBDielectric constant (RT duroid) 22
4 Design of Proposed Structures
Here we have considered the design of proposed structurebased on the specification given in Table 1 These specifi-cations are considered based on the satellite and RADARapplications in which we are targeting C X and Ku bandfrequencies The C band X band and Ku Band defined byan IEEE standard for radio waves and radar engineering withfrequencies that range from 40 to 80GHz 80 to 120GHzand 120 to 180GHz respectively Frequency range of 37 to42GHz is used for the satellite downlink communicationin C band and the band of frequencies from 5925GHz to6425GHz for their uplinks The X band is used for shortrange tracking missile guidance marine radar and airborneintercept It is used especially for radar communicationranges roughly from 829GHz to 114 GHz The Ku band isused for high resolution mapping and satellite altimetry Kuband especially is used for tracking the satellite within theranges roughly from 1287GHz to 1443GHz
From the above applications the proposed structuredesign is targeted at center frequency of 7GHz Physicaldimensions of the first proposed structure are calculated bythe above formula and summarized in Table 2 The wire linestructure of proposed antenna is shown in Figure 3
6 International Journal of Microwave Science and Technology
625 825 1025 1225 1425
minus35
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo63mmrdquob1 = ldquo1856mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1256mmrdquoa1f = ldquo425mmrdquoS11 (dB)
S11 (dB)
S11 (dB)
(a)
625 825 1025 1225 1425
minus45
minus40
minus35
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo73mmrdquob1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo53mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquoS11 (dB)
S11 (dB)
S11 (dB)
(b)
625 825 1025 1225 1425
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo63mmrdquob1 = ldquo1556mmrdquoa1f = ldquo525mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo325mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo225mmrdquoS11 (dB) S11 (dB)
S11 (dB)
(c)
Figure 8 (a) 11987811of logarithmic rectangular slots array antenna with respect to variations in 1st slot position (b) 119878
11of logarithmic rectangular
slots array antennawith respect to variations in 1st slot position (c) 11987811of logarithmic rectangular slots array antennawith respect to variations
in width of 1st slot
International Journal of Microwave Science and Technology 7
Table 2 Calculated parameters
Parameter 119891
119888119886
1015840
119863 119875 119886
119904120576
119903120582
119888120582
119892119908 119886
119905119897
119908119897
119905
Value 71 GHz 142mm 9mm 10mm 2276mm 22 4225mm 2848mm 5504mm 15mm 170mm 30mm
Table 3 Summaries of simulated parameters
Resonant frequency Gain in dB Bandwidth in MHz VSWR Peak return loss in dB705GHz 1085 100 105 minus31431085GHz 75 200 119 minus2100119 GHz 71 250 113 minus2371146GHz 69 400 1097 minus2664
As shown in Figure 4 it contains six rectangular slotsarray whose longitudinal length is varied according to log-arithmic manner We are keeping center-to-center distancebetween two slots as 1424mm (120582
1198922) and center of last slot
to broadside wall as 2136mmThe structure has been simulated using HFSS (High Fre-
quency Structure Simulator) and it generates return lossshown in Figure 5 As shown in Figure 5 the structure gen-erates six resonant frequencies one in C band (705GHz)three in X band (102 1055 and 115 GHz) and two inKu band (128 and 146GHz) respectively These results aretotally expected since the proposed antenna is composedof different resonant slot lengths providing the multibandperformance At all the resonant frequencies VSWR is alsogood which is shown in Figure 6 One of the extraordinaryperformances generated by this structure is shown in Figure 7which represents the gain value that is more than 10 dBin single layer and single array combination compared toother traditional antennas having multilayer and 2 to 3arrays for achieving higher gain Various gain and radiationpatterns of the proposed logarithmic slots array of antennafor different resonant frequencies are shown in Figure 6 Allthe simulation results are summarized in Table 3
It is possible to tune the frequency by changing the geo-metrical position with respect to wave propagation directionand physical dimensions of the slots All these methodsultimately changed the value of reactance of resonators andcoupling of the EM field Here we have demonstrated threepossible methods to tune the response (i) pose of slot (ii)length of slot (iii) width of slot For demonstration andanalysis purpose onlywe applied the above tuningmethods tothe first slot These methods can also be applicable for otherremaining slots Figure 8(a) demonstrates simulation resultof reflection coefficient obtained by changing the positionof first slot which was kept at 120582
1198922 distance with respect
to second slot in longitude direction It shows that whenwe move the slot position in positive longitude direction itimproves the value of return loss and increment in oppositedirection it reduces the value of return loss Figure 8(b)shows the simulation result with increasing the length of thefirst slot It decreases the values of inductance and increasesthe capacitance value Variation in length gave minor effecton a reflection coefficient value Similarly Figure 8(c) is theresult of reflection coefficient with the change in width of
1424mm4mm3376mm
1702mm
0508mm
2136mm
9mm 10mm30mm
Figure 9 2nd proposed structure contains I shape logarithmic slotsarray antenna
m3
m4
m5
m6
m7m8m9
m2 m10
m1
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
700 800 900 1000 1100 1200 1300 1400 1500600
Curve info
Setup1 sweep
Freq (GHz)
Name X Y
m1 77080m2 81210m3 84170m4 87660m5 92910m6 102010m7 104890m8 109930m9 118430m10 137490 minus124121
minus156759minus138911minus147592minus226325minus274168minus103236minus241340minus124315minus180066
S11 (dB)
S 11
(dB)
Figure 10 11987811plot for I shaped logarithmic slots array antenna
the first slot that tunes resonant frequency effectively and alsoproduces very sharp bandwidth
In the second proposed structure instead of takingrectangular shape slots longitudinal I shape is selected whichis shown in Figure 9 Spacing between two slots and centerdistance of last slots from the end boadsie wall are the same as1st proposed design In first I shape slot vertical height of theslot is 4mm and length of slot is 10mm which progressivelyincreases for other slots according to logarthmic nature
This structure is also simulated by using HFSS and itsreturn loss is shwon in Figure 10 This structure radiates atsix resonant frequencies one in C band (77 GHz) three inX band (812 841 876 929 102 1048 1099 1145 and
8 International Journal of Microwave Science and Technology
Y
Z
53483e + 00033392e + 00013301e + 000minus67903e minus 001minus26881e + 000minus46972e + 000minus67063e + 000minus87154e + 000minus10725e + 001minus12734e + 001minus14743e + 001minus16752e + 001minus18761e + 001minus20770e + 001minus22779e + 001minus24788e + 001minus26797e + 001
GainTotal (dB)
(a)
080
160
240
320
90
60
300
150
120
Curve inforETotal
Setup1 LastAdaptiveFreq = 71GHz Theta = 90degldquo ldquordquo rdquo
minus30
minus60
minus90
minus120
minus150minus180
(b)
Figure 11 (a) Gain plot and (b) radiation pattern for I shape logarithmic slots array antenna
1424mm 3376mm
1702mm
0508mm
9mm 10mm30mm
15mm 21mm
Figure 12 3rd proposed structure contains trapezoidal logarithmic slots array antenna
m2
m3
m4m5 m6
m7
m8m1
Curve info
Setup1 sweep
700 800 900 1000 1100 1200 1300 1400 1500600Freq (GHz)
minus3500
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
Name X Y
m1 67300m2 78400m3 103800m4 110700m5 114300m6 121400m7 128100m8 143600 minus183495
minus300236
minus181027minus163299
minus202328
minus270798
minus154970minus159939
S11 (dB)
S 11
(dB)
Figure 13 11987811plot for trapezoidal logarithmic slots array antenna
119 GHz) and two in Ku band (1395 and 145 GHz)The gainplot and radiation pattern for 67GHz frequency are shownin Figures 11(a) and 11(b) which shows that it generates gainof 5 dB which is half compared to first proposed structure
Third proposed structure contains trapezoidal logarith-mic slots array as shown in Figure 12 Distances of all the slots
m1 m2 m3 m4 m5 m6 m7 m8
700 800 900 1000 1100 1200 1300 1400 1500600Freq (GHz)
000500
100015002000250030003500
VSW
R(1)
Curve infoVSWR(1)
Setup1 sweep
Name X Ym1 67200 13759m2 78400 14037m3 103800 10926m4 110700 12157m5 114300 13601m6 121400 12842m7 128000 10823m8 143700 12861
Figure 14 VSWR of 3rd proposed trapezoidal logarithmic slotsarray antenna
are the same as 1st proposed design Simulated result of theproposed structure is shown in Figure 13 which shows higherreturn loss occurring at eight different frequencies two in Cband (67 and 754GHz) four in X band (1025 11 1143 and
International Journal of Microwave Science and Technology 9
10300e + 001
79774e + 000
33329e + 00056551e + 000
10107e + 000minus13115e + 000minus36337e + 000minus59560e + 000minus82782e + 000minus10600e + 001minus12923e + 001minus15245e + 001minus17567e + 001minus19889e + 001minus22211e + 001
minus26856e + 001
minus24534e + 001
GainTotal (dB)
Y
Z
(a)
Curve inforETotal
Setup1 LastAdaptiveFreq = 71GHz Theta = 90degldquo ldquordquo rdquo
minus30
minus90
minus120
minus150
minus180
minus60
200
400
600
800
90
60
300
150
120
(b)
Figure 15 (a) Gain plot and (b) radiation pattern for trapezoidal logarithmic slots array antenna
Figure 16 Fabricated model of logarithmic rectangular slots arrayantenna
5 10 15
minus30
minus25
minus20
minus15
minus10
minus5
0
Simulated S11 (dB)Measured S11 (dB)
Figure 17 11987811of logarithmic rectangular slots array antenna
1214GHz) and Ku band (1281 and 1436GHz) Its VSWR isshown in Figure 14Gain plot and radiation pattern are shownin Figures 15(a) and 15(b) respectively It gives more than10 dB gain at 67 GHz frequency
Simulated gainMeasured gain
00 30 60 90 120 150 180 210 240 270 300 360330
1
2
3
4
5
6
7
8
9
10
Figure 18 Gain of logarithmic rectangular slots array antenna
5 Measured Results
Logarithmic rectangular slots array antenna has been fabri-cated on Rogers RT Duroid 5880 high frequency substratewith a thickness of 0787mm relative permittivity of 22 andrelative permeability of 1 and loss tangent of 00009 The topside of the antenna has logarithmic slots and the other side isground planeThe photograph of fabricated antenna is shownin Figure 16
The antenna 11987811parameter and gain are measured using
the Vector Network Analyzer MVNA-8-350 with probe sta-tion The simulated and measured 119878
11parameter for antenna
is shown in Figure 17 A slight difference is observed between
10 International Journal of Microwave Science and Technology
Radiation efficiency
100
095
090
085
HFSSCurve info
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Radiation efficiency
Radiation efficiency
Setup1 LastAdaptiveFreq = 71GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Freq = 71GHz Theta = 10degldquo ldquordquo rdquo
Freq = 71GHz Theta = 20degldquo ldquordquo rdquo
Freq = 71GHz Theta = 50degldquo ldquordquo rdquo
Freq = 71GHz Theta = 40degldquo ldquordquo rdquo
Freq = 71GHz Theta = 60degldquo ldquordquo rdquo
Freq = 71GHz Theta = 30degldquo ldquordquo rdquo
(a)
Radiation efficiency
HFSS design2Curve info
096
092
088
084
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 10degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 20degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 50degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 40degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 60degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 30degldquo ldquordquo rdquo
(b)
Figure 19 Radiation efficiency of logarithmic rectangular slots array antenna in (a) C band and (b) X band
the measured value and simulated value The differencebetween the measured and simulated 119878
11of the antenna is
caused by the microstrip to SIW transitionThe simulated and measured gain of the antenna are
shown in Figure 18Themaximummeasured gain is also veryclose to 10 dB at 7GHz for the antenna which is max Themeasured result shows that the bandwidth of the antennacovers over 300MHz while the gain of the antenna is keptalmost constantwithin such awide bandwidth of the antennaSimulation results specify that metallic and dielectric lossesdo not have a substantial effect on the bandwidth andmatching condition of the antenna while they decrease themeasured gain of antenna by 05 dB The apparent differencebetween the simulation and measured gains might be dueto the calibration linked tolerance range of the antennareference in anechoic chamber
The radiation pattern of the antenna at resonant fre-quency is shown in Figure 18 The radiation pattern mea-surement is carried out in a conventional far field anechoicchamber which uses a V connector to connect the antennaDue to the size of the connector compared to the antenna therear radiation patterns were not incorporated in the resultsHowever the similar effects were observed in the simulationresults and most significantly the radiating behavior of theantenna is very similar to simulation results As shown inFigures 19(a) and 19(b) they represent the radiation efficiencyin C band and X band respectively which is 92 and 88
6 Observation and Discussion
From the simulation results we have observed the followingthings
(i) All the structure gives six or more than six resonantfrequencies in C band X band and Ku band
(ii) Gain generated by rectangular and trapezoidal log-arithmic slots array antenna is more than 10 dBcompared to I shape logarithmic slots array antenna
(iii) Isolation between two radiation bands ismuch higherin trapezoidal logarithmic slots array antenna andalso generates low leakage loss in stop band
(iv) Size of entire proposed antennas is compact com-pared to traditional antennas which are proposed forhigh gain applications
(v) Bandwidth produced by all the antennas at resonantfrequencies is more than 100MHz
7 Conclusion
From the design and simulation results it is clear that allthe antennas are compact in size and they are capable togenerate multiband frequencies which are very importantfactors for the proposed design process of antennas Antennasbased on SIW technology have been proposed in this paper
International Journal of Microwave Science and Technology 11
These structures can find many applications in C band and Xband for radar and remote sensingmechanism and are one ofthe major areas in docking satellite where communication isdone in C band while ranging is carried out in X band So thisantenna fulfilled both requirements instead of using two dif-ferent antennas Significant increment of gain parameter hasbeen obtained for introduction of more number and varietyof shapes of slots Compared to identical slots logarithmicslots give higher gain The effect has been extensively studiedunlike any other recent publication in this fieldThe structureis very simple and development of the prototype is easy inpresence of advanced PCB fabrication technology
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] P N Richardson and H Y Lee ldquoDesign and analysis of slottedwaveguide arraysrdquoMicrowave Journal vol 31 pp 109ndash125 1988
[2] S Ravish A Patel V V Dwivedi and H B Pandya ldquoDesigndevelopment and fabrication of post coupled band pass waveg-uide filter at 112 GHz for radiometerrdquo Microwave Journal vol51 2008
[3] A Patel Y Kosta N Chhasatia and K Pandya ldquoMultiple bandwaveguide based microwave resonatorrdquo in Proceedings of the1st International Conference on Advances in Engineering Scienceand Management (ICAESM rsquo12) pp 84ndash87 NagapattinamIndia March 2012
[4] S R Rengarajan ldquoCompound radiating slots in a broad wall ofa rectangular waveguiderdquo IEEE Transactions on Antennas andPropagation vol 37 no 9 pp 1116ndash1123 1989
[5] A Patel and Y P Kosta ldquoMultiple-band waveguide based band-stop filterrdquo International Journal of Applied Electromagnetics andMechanics vol 47 no 2 pp 563ndash581 2015
[6] S Fallahzadeh H Bahrami and M Tayarani ldquoA novel dual-band bandstop waveguide filter using split ring resonatorsrdquoProgress in Electromagnetics Research Letters vol 12 pp 133ndash139 2009
[7] I Ohta Y Yumita K Toda and M Kishihara ldquoCruciformdirectional couplers in H-plane rectangular waveguiderdquo in Pro-ceedings of the Asia-Pacific Microwave Conference (APMC rsquo05)vol 2 December 2005
[8] A Patel Y Kosta N Chhasatia and F Raval ldquoDesign andfabrication of microwave waveguide resonator with improvedcharacteristic responserdquo European Journal of Scientific Researchvol 102 no 2 pp 163ndash174 2013
[9] R S Elliott and L A Kurtz ldquoThe design of small slot arraysrdquoIEEE Transactions on Antennas and Propagation vol 26 no 2pp 214ndash219 1978
[10] R S Elliott ldquoAn improved design procedure for small arrays ofshunt slotsrdquo IEEE Transactions on Antennas and Propagationvol 31 no 1 pp 48ndash53 1983
[11] A F Stevenson ldquoTheory of slots in rectangular wave-guidesrdquoJournal of Applied Physics vol 19 pp 24ndash38 1948
[12] W Coburn M Litz J Miletta N Tesny L Dilks and B KingldquoA slotted-waveguide array for high-power microwave trans-missionrdquo Progress Report for FY 2000 US Army ResearchLaboratory Adelphi Md USA 2001
[13] F Raval Y P Kosta J Makwana and A V Patel ldquoDesign amp im-plementation of reduced size microstrip patch antenna withmetamaterial defected ground planerdquo in Proceedings of the 2ndInternational Conference on Communication and Signal Proc-essing (ICCSP rsquo13) pp 186ndash190 IEEE Melmaruvathur IndiaApril 2013
[14] M Kahrizi T K Sarkar and Z AMaricevic ldquoAnalysis of a wideradiating slot in the ground plane of a microstrip linerdquo IEEETransactions onMicrowaveTheory and Techniques vol 41 no 1pp 29ndash37 1993
[15] J Galejst ldquoAdmittance of a rectangular slot which is backed bya rectangular cavityrdquo IEEE Transactions on Antennas and Prop-agation vol 11 no 2 pp 119ndash126 1963
[16] K-LWongCompact andBroadbandMicrostripAntennas JohnWiley amp Sons New York NY USA 2002
[17] W-S Chen ldquoSingle-feed dual-frequency rectangularmicrostripantenna with square slotrdquo Electronics Letters vol 34 no 3 pp231ndash232 1998
[18] D Busuioc M Shahabadi A Borji G Shaker and S Safavi-Naeini ldquoSubstrate integrated waveguide antenna feedmdashdesignmethodology and validationrdquo in Proceedings of the IEEE Anten-nas and Propagation Society International Symposium (AP-Srsquo07) pp 2666ndash2669 Honolulu Hawaii USA June 2007
[19] H Kumar R Jadhav and S Ranade ldquoA review on substrateintegrated waveguide and its microstrip interconnectrdquo Journalof Electronics and Communication Engineering vol 3 no 5 pp36ndash40 2012
[20] M Bozzi F XuDDeslandes andKWu ldquoModeling and designconsiderations for substrate integrated waveguide circuits andcomponentsrdquo in Proceedings of the 8th International Conferenceon Telecommunications in Modern Satellite Cable and Broad-casting Services (TELSIKS rsquo07) pp P-7ndashP-16 IEEE Nis SerbiaSeptember 2007
[21] S Moitra A Mukhopadhyay and A Bhattacharjee ldquoKu-bandsubstrate integrated waveguide (SIW) slot array antenna fornext generation networksrdquo Global Journal of Computer Scienceand Technology E Network Web amp Security vol 13 no 5 pp11ndash16 2013
[22] A J Farrall and P R Young ldquoIntegrated waveguide slot anten-nasrdquo Electronics Letters vol 40 no 16 pp 974ndash975 2004
[23] D PozarMicrowave Engineering JohnWiley amp Sons HobokenNJ USA 3rd edition 2005
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
4 International Journal of Microwave Science and Technology
2008001400
90
60
300
150
120
200
400
600800
90
60
300
150
120
160320480640
90
60
300
150
120
Antenna gain plot for 108GHz
Antenna gain plot for 119GHz
Antenna gain plot for 705GHz
Radiation pattern for solution frequency 119GHz
Radiation pattern for solution frequency 108GHz
Radiation pattern for solution frequency 705GHz
minus400
minus30
minus60
minus90
minus120
minus150minus180
minus30
minus60
minus90
minus120
minus150
minus180
minus30
minus60
minus90
minus120
minus150minus180
Curve inforETotal (dB)
Setup1 LastAdaptiveFreq = 705GHz Theta = 90degldquo ldquordquo rdquo
rETotalCurve info
Setup1 LastAdaptiveFreq = 1085GHz Theta = 90degldquo ldquordquo rdquo
Curve info
Setup1 LastAdaptiverETotal
Freq = 119GHz Theta = 90degldquo ldquordquo rdquo
71077e + 00050667e + 00030257e + 00098467e minus 001minus10563e + 000
minus51383e + 000minus71793e + 000minus92203e + 000minus11261e + 001minus13302e + 001minus15343e + 001minus17384e + 001minus19425e + 001minus21466e + 001minus23507e + 001minus25548e + 001
GainTotal (dB)
GainTotal (dB)
GainTotal (dB)
X
Y
Z
X
Y
Z
X
Y
Z
75069e + 00057476e + 00039883e + 00022290e + 00046965e minus 001minus12896e + 000minus30489e + 000minus48082e + 000minus65675e + 000minus83268e + 000minus10086e + 001minus11845e + 001minus13605e + 001minus15364e + 001minus17123e + 001minus18883e + 001minus20642e + 001
10685e + 001
40077e + 000
minus26697e + 000
minus93470e + 000
minus16024e + 001
minus22702e + 001
minus29379e + 001
minus30973e + 000
Figure 7 Continued
International Journal of Microwave Science and Technology 5
200
400600800
90
60
300
150
120
Antenna gain plot for 146GHz Radiation pattern for solution frequency 146GHz
minus30
minus60
minus90
minus120
minus150minus180
Curve info
Setup1 LastAdaptiverETotal
Freq = 146GHz Theta = 90degldquo ldquordquo rdquo
X
Y
Z
69798e + 00048590e + 00027382e + 00061746e minus 001minus15033e + 000minus36241e + 000minus57449e + 000minus78657e + 000minus99865e + 000minus12107e + 001minus14228e + 001minus16349e + 001minus18470e + 001minus20590e + 001minus22711e + 001minus24832e + 001minus26953e + 001
GainTotal (dB)
Figure 7 Gain plots and radiation patterns at different resonant frequencies
The width of tapper at feed side is 04 times the open-ing of patch antenna
119886
119905= 04 (119886 minus 119889) (5)
The width of tapper at antenna side is
119908 =
119888
2119891radic(120576
119903+ 1) 2
(6)
Finally length of tapper for impedance match is given by
119897
119905=
119899 lowast 120582
119892
4
where 119899 = 1 2 3 (7)
It is already derived that the gain and beamwidth formula forthe slots have equal distance end to end and spacing along thewaveguide A simple procedure to calculate the gain of a slotantenna is on array of dipoles As we double the dipole slotsthey increase the double gain So for 16 slots it is possible toget gain of 12 dB Each time we double the number of dipoleswe double the gain or add 3 dB Thus a 16-slot array wouldhave a gain of about 12 dB Gain can be calculated from theequation 119866 = 10 log(119873) dB for119873 total slots
Now include the effect of gain with spacing of slot betterto be described as
Gain = 10 log119873 lowast slotspacing120582
0
dB (8)
Calculated gain is always equal to average gain nowbeamwidth is given by
Beamwidth = 507120582
0
(1198732) lowast slotspacingDegree (9)
Table 1 Specification of the proposed structure
Parameters ValueCenter frequency 7GHzReturn loss gtminus10 dBVSWR 1Gain gt5 dBDielectric constant (RT duroid) 22
4 Design of Proposed Structures
Here we have considered the design of proposed structurebased on the specification given in Table 1 These specifi-cations are considered based on the satellite and RADARapplications in which we are targeting C X and Ku bandfrequencies The C band X band and Ku Band defined byan IEEE standard for radio waves and radar engineering withfrequencies that range from 40 to 80GHz 80 to 120GHzand 120 to 180GHz respectively Frequency range of 37 to42GHz is used for the satellite downlink communicationin C band and the band of frequencies from 5925GHz to6425GHz for their uplinks The X band is used for shortrange tracking missile guidance marine radar and airborneintercept It is used especially for radar communicationranges roughly from 829GHz to 114 GHz The Ku band isused for high resolution mapping and satellite altimetry Kuband especially is used for tracking the satellite within theranges roughly from 1287GHz to 1443GHz
From the above applications the proposed structuredesign is targeted at center frequency of 7GHz Physicaldimensions of the first proposed structure are calculated bythe above formula and summarized in Table 2 The wire linestructure of proposed antenna is shown in Figure 3
6 International Journal of Microwave Science and Technology
625 825 1025 1225 1425
minus35
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo63mmrdquob1 = ldquo1856mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1256mmrdquoa1f = ldquo425mmrdquoS11 (dB)
S11 (dB)
S11 (dB)
(a)
625 825 1025 1225 1425
minus45
minus40
minus35
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo73mmrdquob1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo53mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquoS11 (dB)
S11 (dB)
S11 (dB)
(b)
625 825 1025 1225 1425
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo63mmrdquob1 = ldquo1556mmrdquoa1f = ldquo525mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo325mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo225mmrdquoS11 (dB) S11 (dB)
S11 (dB)
(c)
Figure 8 (a) 11987811of logarithmic rectangular slots array antenna with respect to variations in 1st slot position (b) 119878
11of logarithmic rectangular
slots array antennawith respect to variations in 1st slot position (c) 11987811of logarithmic rectangular slots array antennawith respect to variations
in width of 1st slot
International Journal of Microwave Science and Technology 7
Table 2 Calculated parameters
Parameter 119891
119888119886
1015840
119863 119875 119886
119904120576
119903120582
119888120582
119892119908 119886
119905119897
119908119897
119905
Value 71 GHz 142mm 9mm 10mm 2276mm 22 4225mm 2848mm 5504mm 15mm 170mm 30mm
Table 3 Summaries of simulated parameters
Resonant frequency Gain in dB Bandwidth in MHz VSWR Peak return loss in dB705GHz 1085 100 105 minus31431085GHz 75 200 119 minus2100119 GHz 71 250 113 minus2371146GHz 69 400 1097 minus2664
As shown in Figure 4 it contains six rectangular slotsarray whose longitudinal length is varied according to log-arithmic manner We are keeping center-to-center distancebetween two slots as 1424mm (120582
1198922) and center of last slot
to broadside wall as 2136mmThe structure has been simulated using HFSS (High Fre-
quency Structure Simulator) and it generates return lossshown in Figure 5 As shown in Figure 5 the structure gen-erates six resonant frequencies one in C band (705GHz)three in X band (102 1055 and 115 GHz) and two inKu band (128 and 146GHz) respectively These results aretotally expected since the proposed antenna is composedof different resonant slot lengths providing the multibandperformance At all the resonant frequencies VSWR is alsogood which is shown in Figure 6 One of the extraordinaryperformances generated by this structure is shown in Figure 7which represents the gain value that is more than 10 dBin single layer and single array combination compared toother traditional antennas having multilayer and 2 to 3arrays for achieving higher gain Various gain and radiationpatterns of the proposed logarithmic slots array of antennafor different resonant frequencies are shown in Figure 6 Allthe simulation results are summarized in Table 3
It is possible to tune the frequency by changing the geo-metrical position with respect to wave propagation directionand physical dimensions of the slots All these methodsultimately changed the value of reactance of resonators andcoupling of the EM field Here we have demonstrated threepossible methods to tune the response (i) pose of slot (ii)length of slot (iii) width of slot For demonstration andanalysis purpose onlywe applied the above tuningmethods tothe first slot These methods can also be applicable for otherremaining slots Figure 8(a) demonstrates simulation resultof reflection coefficient obtained by changing the positionof first slot which was kept at 120582
1198922 distance with respect
to second slot in longitude direction It shows that whenwe move the slot position in positive longitude direction itimproves the value of return loss and increment in oppositedirection it reduces the value of return loss Figure 8(b)shows the simulation result with increasing the length of thefirst slot It decreases the values of inductance and increasesthe capacitance value Variation in length gave minor effecton a reflection coefficient value Similarly Figure 8(c) is theresult of reflection coefficient with the change in width of
1424mm4mm3376mm
1702mm
0508mm
2136mm
9mm 10mm30mm
Figure 9 2nd proposed structure contains I shape logarithmic slotsarray antenna
m3
m4
m5
m6
m7m8m9
m2 m10
m1
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
700 800 900 1000 1100 1200 1300 1400 1500600
Curve info
Setup1 sweep
Freq (GHz)
Name X Y
m1 77080m2 81210m3 84170m4 87660m5 92910m6 102010m7 104890m8 109930m9 118430m10 137490 minus124121
minus156759minus138911minus147592minus226325minus274168minus103236minus241340minus124315minus180066
S11 (dB)
S 11
(dB)
Figure 10 11987811plot for I shaped logarithmic slots array antenna
the first slot that tunes resonant frequency effectively and alsoproduces very sharp bandwidth
In the second proposed structure instead of takingrectangular shape slots longitudinal I shape is selected whichis shown in Figure 9 Spacing between two slots and centerdistance of last slots from the end boadsie wall are the same as1st proposed design In first I shape slot vertical height of theslot is 4mm and length of slot is 10mm which progressivelyincreases for other slots according to logarthmic nature
This structure is also simulated by using HFSS and itsreturn loss is shwon in Figure 10 This structure radiates atsix resonant frequencies one in C band (77 GHz) three inX band (812 841 876 929 102 1048 1099 1145 and
8 International Journal of Microwave Science and Technology
Y
Z
53483e + 00033392e + 00013301e + 000minus67903e minus 001minus26881e + 000minus46972e + 000minus67063e + 000minus87154e + 000minus10725e + 001minus12734e + 001minus14743e + 001minus16752e + 001minus18761e + 001minus20770e + 001minus22779e + 001minus24788e + 001minus26797e + 001
GainTotal (dB)
(a)
080
160
240
320
90
60
300
150
120
Curve inforETotal
Setup1 LastAdaptiveFreq = 71GHz Theta = 90degldquo ldquordquo rdquo
minus30
minus60
minus90
minus120
minus150minus180
(b)
Figure 11 (a) Gain plot and (b) radiation pattern for I shape logarithmic slots array antenna
1424mm 3376mm
1702mm
0508mm
9mm 10mm30mm
15mm 21mm
Figure 12 3rd proposed structure contains trapezoidal logarithmic slots array antenna
m2
m3
m4m5 m6
m7
m8m1
Curve info
Setup1 sweep
700 800 900 1000 1100 1200 1300 1400 1500600Freq (GHz)
minus3500
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
Name X Y
m1 67300m2 78400m3 103800m4 110700m5 114300m6 121400m7 128100m8 143600 minus183495
minus300236
minus181027minus163299
minus202328
minus270798
minus154970minus159939
S11 (dB)
S 11
(dB)
Figure 13 11987811plot for trapezoidal logarithmic slots array antenna
119 GHz) and two in Ku band (1395 and 145 GHz)The gainplot and radiation pattern for 67GHz frequency are shownin Figures 11(a) and 11(b) which shows that it generates gainof 5 dB which is half compared to first proposed structure
Third proposed structure contains trapezoidal logarith-mic slots array as shown in Figure 12 Distances of all the slots
m1 m2 m3 m4 m5 m6 m7 m8
700 800 900 1000 1100 1200 1300 1400 1500600Freq (GHz)
000500
100015002000250030003500
VSW
R(1)
Curve infoVSWR(1)
Setup1 sweep
Name X Ym1 67200 13759m2 78400 14037m3 103800 10926m4 110700 12157m5 114300 13601m6 121400 12842m7 128000 10823m8 143700 12861
Figure 14 VSWR of 3rd proposed trapezoidal logarithmic slotsarray antenna
are the same as 1st proposed design Simulated result of theproposed structure is shown in Figure 13 which shows higherreturn loss occurring at eight different frequencies two in Cband (67 and 754GHz) four in X band (1025 11 1143 and
International Journal of Microwave Science and Technology 9
10300e + 001
79774e + 000
33329e + 00056551e + 000
10107e + 000minus13115e + 000minus36337e + 000minus59560e + 000minus82782e + 000minus10600e + 001minus12923e + 001minus15245e + 001minus17567e + 001minus19889e + 001minus22211e + 001
minus26856e + 001
minus24534e + 001
GainTotal (dB)
Y
Z
(a)
Curve inforETotal
Setup1 LastAdaptiveFreq = 71GHz Theta = 90degldquo ldquordquo rdquo
minus30
minus90
minus120
minus150
minus180
minus60
200
400
600
800
90
60
300
150
120
(b)
Figure 15 (a) Gain plot and (b) radiation pattern for trapezoidal logarithmic slots array antenna
Figure 16 Fabricated model of logarithmic rectangular slots arrayantenna
5 10 15
minus30
minus25
minus20
minus15
minus10
minus5
0
Simulated S11 (dB)Measured S11 (dB)
Figure 17 11987811of logarithmic rectangular slots array antenna
1214GHz) and Ku band (1281 and 1436GHz) Its VSWR isshown in Figure 14Gain plot and radiation pattern are shownin Figures 15(a) and 15(b) respectively It gives more than10 dB gain at 67 GHz frequency
Simulated gainMeasured gain
00 30 60 90 120 150 180 210 240 270 300 360330
1
2
3
4
5
6
7
8
9
10
Figure 18 Gain of logarithmic rectangular slots array antenna
5 Measured Results
Logarithmic rectangular slots array antenna has been fabri-cated on Rogers RT Duroid 5880 high frequency substratewith a thickness of 0787mm relative permittivity of 22 andrelative permeability of 1 and loss tangent of 00009 The topside of the antenna has logarithmic slots and the other side isground planeThe photograph of fabricated antenna is shownin Figure 16
The antenna 11987811parameter and gain are measured using
the Vector Network Analyzer MVNA-8-350 with probe sta-tion The simulated and measured 119878
11parameter for antenna
is shown in Figure 17 A slight difference is observed between
10 International Journal of Microwave Science and Technology
Radiation efficiency
100
095
090
085
HFSSCurve info
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Radiation efficiency
Radiation efficiency
Setup1 LastAdaptiveFreq = 71GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Freq = 71GHz Theta = 10degldquo ldquordquo rdquo
Freq = 71GHz Theta = 20degldquo ldquordquo rdquo
Freq = 71GHz Theta = 50degldquo ldquordquo rdquo
Freq = 71GHz Theta = 40degldquo ldquordquo rdquo
Freq = 71GHz Theta = 60degldquo ldquordquo rdquo
Freq = 71GHz Theta = 30degldquo ldquordquo rdquo
(a)
Radiation efficiency
HFSS design2Curve info
096
092
088
084
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 10degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 20degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 50degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 40degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 60degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 30degldquo ldquordquo rdquo
(b)
Figure 19 Radiation efficiency of logarithmic rectangular slots array antenna in (a) C band and (b) X band
the measured value and simulated value The differencebetween the measured and simulated 119878
11of the antenna is
caused by the microstrip to SIW transitionThe simulated and measured gain of the antenna are
shown in Figure 18Themaximummeasured gain is also veryclose to 10 dB at 7GHz for the antenna which is max Themeasured result shows that the bandwidth of the antennacovers over 300MHz while the gain of the antenna is keptalmost constantwithin such awide bandwidth of the antennaSimulation results specify that metallic and dielectric lossesdo not have a substantial effect on the bandwidth andmatching condition of the antenna while they decrease themeasured gain of antenna by 05 dB The apparent differencebetween the simulation and measured gains might be dueto the calibration linked tolerance range of the antennareference in anechoic chamber
The radiation pattern of the antenna at resonant fre-quency is shown in Figure 18 The radiation pattern mea-surement is carried out in a conventional far field anechoicchamber which uses a V connector to connect the antennaDue to the size of the connector compared to the antenna therear radiation patterns were not incorporated in the resultsHowever the similar effects were observed in the simulationresults and most significantly the radiating behavior of theantenna is very similar to simulation results As shown inFigures 19(a) and 19(b) they represent the radiation efficiencyin C band and X band respectively which is 92 and 88
6 Observation and Discussion
From the simulation results we have observed the followingthings
(i) All the structure gives six or more than six resonantfrequencies in C band X band and Ku band
(ii) Gain generated by rectangular and trapezoidal log-arithmic slots array antenna is more than 10 dBcompared to I shape logarithmic slots array antenna
(iii) Isolation between two radiation bands ismuch higherin trapezoidal logarithmic slots array antenna andalso generates low leakage loss in stop band
(iv) Size of entire proposed antennas is compact com-pared to traditional antennas which are proposed forhigh gain applications
(v) Bandwidth produced by all the antennas at resonantfrequencies is more than 100MHz
7 Conclusion
From the design and simulation results it is clear that allthe antennas are compact in size and they are capable togenerate multiband frequencies which are very importantfactors for the proposed design process of antennas Antennasbased on SIW technology have been proposed in this paper
International Journal of Microwave Science and Technology 11
These structures can find many applications in C band and Xband for radar and remote sensingmechanism and are one ofthe major areas in docking satellite where communication isdone in C band while ranging is carried out in X band So thisantenna fulfilled both requirements instead of using two dif-ferent antennas Significant increment of gain parameter hasbeen obtained for introduction of more number and varietyof shapes of slots Compared to identical slots logarithmicslots give higher gain The effect has been extensively studiedunlike any other recent publication in this fieldThe structureis very simple and development of the prototype is easy inpresence of advanced PCB fabrication technology
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] P N Richardson and H Y Lee ldquoDesign and analysis of slottedwaveguide arraysrdquoMicrowave Journal vol 31 pp 109ndash125 1988
[2] S Ravish A Patel V V Dwivedi and H B Pandya ldquoDesigndevelopment and fabrication of post coupled band pass waveg-uide filter at 112 GHz for radiometerrdquo Microwave Journal vol51 2008
[3] A Patel Y Kosta N Chhasatia and K Pandya ldquoMultiple bandwaveguide based microwave resonatorrdquo in Proceedings of the1st International Conference on Advances in Engineering Scienceand Management (ICAESM rsquo12) pp 84ndash87 NagapattinamIndia March 2012
[4] S R Rengarajan ldquoCompound radiating slots in a broad wall ofa rectangular waveguiderdquo IEEE Transactions on Antennas andPropagation vol 37 no 9 pp 1116ndash1123 1989
[5] A Patel and Y P Kosta ldquoMultiple-band waveguide based band-stop filterrdquo International Journal of Applied Electromagnetics andMechanics vol 47 no 2 pp 563ndash581 2015
[6] S Fallahzadeh H Bahrami and M Tayarani ldquoA novel dual-band bandstop waveguide filter using split ring resonatorsrdquoProgress in Electromagnetics Research Letters vol 12 pp 133ndash139 2009
[7] I Ohta Y Yumita K Toda and M Kishihara ldquoCruciformdirectional couplers in H-plane rectangular waveguiderdquo in Pro-ceedings of the Asia-Pacific Microwave Conference (APMC rsquo05)vol 2 December 2005
[8] A Patel Y Kosta N Chhasatia and F Raval ldquoDesign andfabrication of microwave waveguide resonator with improvedcharacteristic responserdquo European Journal of Scientific Researchvol 102 no 2 pp 163ndash174 2013
[9] R S Elliott and L A Kurtz ldquoThe design of small slot arraysrdquoIEEE Transactions on Antennas and Propagation vol 26 no 2pp 214ndash219 1978
[10] R S Elliott ldquoAn improved design procedure for small arrays ofshunt slotsrdquo IEEE Transactions on Antennas and Propagationvol 31 no 1 pp 48ndash53 1983
[11] A F Stevenson ldquoTheory of slots in rectangular wave-guidesrdquoJournal of Applied Physics vol 19 pp 24ndash38 1948
[12] W Coburn M Litz J Miletta N Tesny L Dilks and B KingldquoA slotted-waveguide array for high-power microwave trans-missionrdquo Progress Report for FY 2000 US Army ResearchLaboratory Adelphi Md USA 2001
[13] F Raval Y P Kosta J Makwana and A V Patel ldquoDesign amp im-plementation of reduced size microstrip patch antenna withmetamaterial defected ground planerdquo in Proceedings of the 2ndInternational Conference on Communication and Signal Proc-essing (ICCSP rsquo13) pp 186ndash190 IEEE Melmaruvathur IndiaApril 2013
[14] M Kahrizi T K Sarkar and Z AMaricevic ldquoAnalysis of a wideradiating slot in the ground plane of a microstrip linerdquo IEEETransactions onMicrowaveTheory and Techniques vol 41 no 1pp 29ndash37 1993
[15] J Galejst ldquoAdmittance of a rectangular slot which is backed bya rectangular cavityrdquo IEEE Transactions on Antennas and Prop-agation vol 11 no 2 pp 119ndash126 1963
[16] K-LWongCompact andBroadbandMicrostripAntennas JohnWiley amp Sons New York NY USA 2002
[17] W-S Chen ldquoSingle-feed dual-frequency rectangularmicrostripantenna with square slotrdquo Electronics Letters vol 34 no 3 pp231ndash232 1998
[18] D Busuioc M Shahabadi A Borji G Shaker and S Safavi-Naeini ldquoSubstrate integrated waveguide antenna feedmdashdesignmethodology and validationrdquo in Proceedings of the IEEE Anten-nas and Propagation Society International Symposium (AP-Srsquo07) pp 2666ndash2669 Honolulu Hawaii USA June 2007
[19] H Kumar R Jadhav and S Ranade ldquoA review on substrateintegrated waveguide and its microstrip interconnectrdquo Journalof Electronics and Communication Engineering vol 3 no 5 pp36ndash40 2012
[20] M Bozzi F XuDDeslandes andKWu ldquoModeling and designconsiderations for substrate integrated waveguide circuits andcomponentsrdquo in Proceedings of the 8th International Conferenceon Telecommunications in Modern Satellite Cable and Broad-casting Services (TELSIKS rsquo07) pp P-7ndashP-16 IEEE Nis SerbiaSeptember 2007
[21] S Moitra A Mukhopadhyay and A Bhattacharjee ldquoKu-bandsubstrate integrated waveguide (SIW) slot array antenna fornext generation networksrdquo Global Journal of Computer Scienceand Technology E Network Web amp Security vol 13 no 5 pp11ndash16 2013
[22] A J Farrall and P R Young ldquoIntegrated waveguide slot anten-nasrdquo Electronics Letters vol 40 no 16 pp 974ndash975 2004
[23] D PozarMicrowave Engineering JohnWiley amp Sons HobokenNJ USA 3rd edition 2005
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
International Journal of Microwave Science and Technology 5
200
400600800
90
60
300
150
120
Antenna gain plot for 146GHz Radiation pattern for solution frequency 146GHz
minus30
minus60
minus90
minus120
minus150minus180
Curve info
Setup1 LastAdaptiverETotal
Freq = 146GHz Theta = 90degldquo ldquordquo rdquo
X
Y
Z
69798e + 00048590e + 00027382e + 00061746e minus 001minus15033e + 000minus36241e + 000minus57449e + 000minus78657e + 000minus99865e + 000minus12107e + 001minus14228e + 001minus16349e + 001minus18470e + 001minus20590e + 001minus22711e + 001minus24832e + 001minus26953e + 001
GainTotal (dB)
Figure 7 Gain plots and radiation patterns at different resonant frequencies
The width of tapper at feed side is 04 times the open-ing of patch antenna
119886
119905= 04 (119886 minus 119889) (5)
The width of tapper at antenna side is
119908 =
119888
2119891radic(120576
119903+ 1) 2
(6)
Finally length of tapper for impedance match is given by
119897
119905=
119899 lowast 120582
119892
4
where 119899 = 1 2 3 (7)
It is already derived that the gain and beamwidth formula forthe slots have equal distance end to end and spacing along thewaveguide A simple procedure to calculate the gain of a slotantenna is on array of dipoles As we double the dipole slotsthey increase the double gain So for 16 slots it is possible toget gain of 12 dB Each time we double the number of dipoleswe double the gain or add 3 dB Thus a 16-slot array wouldhave a gain of about 12 dB Gain can be calculated from theequation 119866 = 10 log(119873) dB for119873 total slots
Now include the effect of gain with spacing of slot betterto be described as
Gain = 10 log119873 lowast slotspacing120582
0
dB (8)
Calculated gain is always equal to average gain nowbeamwidth is given by
Beamwidth = 507120582
0
(1198732) lowast slotspacingDegree (9)
Table 1 Specification of the proposed structure
Parameters ValueCenter frequency 7GHzReturn loss gtminus10 dBVSWR 1Gain gt5 dBDielectric constant (RT duroid) 22
4 Design of Proposed Structures
Here we have considered the design of proposed structurebased on the specification given in Table 1 These specifi-cations are considered based on the satellite and RADARapplications in which we are targeting C X and Ku bandfrequencies The C band X band and Ku Band defined byan IEEE standard for radio waves and radar engineering withfrequencies that range from 40 to 80GHz 80 to 120GHzand 120 to 180GHz respectively Frequency range of 37 to42GHz is used for the satellite downlink communicationin C band and the band of frequencies from 5925GHz to6425GHz for their uplinks The X band is used for shortrange tracking missile guidance marine radar and airborneintercept It is used especially for radar communicationranges roughly from 829GHz to 114 GHz The Ku band isused for high resolution mapping and satellite altimetry Kuband especially is used for tracking the satellite within theranges roughly from 1287GHz to 1443GHz
From the above applications the proposed structuredesign is targeted at center frequency of 7GHz Physicaldimensions of the first proposed structure are calculated bythe above formula and summarized in Table 2 The wire linestructure of proposed antenna is shown in Figure 3
6 International Journal of Microwave Science and Technology
625 825 1025 1225 1425
minus35
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo63mmrdquob1 = ldquo1856mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1256mmrdquoa1f = ldquo425mmrdquoS11 (dB)
S11 (dB)
S11 (dB)
(a)
625 825 1025 1225 1425
minus45
minus40
minus35
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo73mmrdquob1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo53mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquoS11 (dB)
S11 (dB)
S11 (dB)
(b)
625 825 1025 1225 1425
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo63mmrdquob1 = ldquo1556mmrdquoa1f = ldquo525mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo325mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo225mmrdquoS11 (dB) S11 (dB)
S11 (dB)
(c)
Figure 8 (a) 11987811of logarithmic rectangular slots array antenna with respect to variations in 1st slot position (b) 119878
11of logarithmic rectangular
slots array antennawith respect to variations in 1st slot position (c) 11987811of logarithmic rectangular slots array antennawith respect to variations
in width of 1st slot
International Journal of Microwave Science and Technology 7
Table 2 Calculated parameters
Parameter 119891
119888119886
1015840
119863 119875 119886
119904120576
119903120582
119888120582
119892119908 119886
119905119897
119908119897
119905
Value 71 GHz 142mm 9mm 10mm 2276mm 22 4225mm 2848mm 5504mm 15mm 170mm 30mm
Table 3 Summaries of simulated parameters
Resonant frequency Gain in dB Bandwidth in MHz VSWR Peak return loss in dB705GHz 1085 100 105 minus31431085GHz 75 200 119 minus2100119 GHz 71 250 113 minus2371146GHz 69 400 1097 minus2664
As shown in Figure 4 it contains six rectangular slotsarray whose longitudinal length is varied according to log-arithmic manner We are keeping center-to-center distancebetween two slots as 1424mm (120582
1198922) and center of last slot
to broadside wall as 2136mmThe structure has been simulated using HFSS (High Fre-
quency Structure Simulator) and it generates return lossshown in Figure 5 As shown in Figure 5 the structure gen-erates six resonant frequencies one in C band (705GHz)three in X band (102 1055 and 115 GHz) and two inKu band (128 and 146GHz) respectively These results aretotally expected since the proposed antenna is composedof different resonant slot lengths providing the multibandperformance At all the resonant frequencies VSWR is alsogood which is shown in Figure 6 One of the extraordinaryperformances generated by this structure is shown in Figure 7which represents the gain value that is more than 10 dBin single layer and single array combination compared toother traditional antennas having multilayer and 2 to 3arrays for achieving higher gain Various gain and radiationpatterns of the proposed logarithmic slots array of antennafor different resonant frequencies are shown in Figure 6 Allthe simulation results are summarized in Table 3
It is possible to tune the frequency by changing the geo-metrical position with respect to wave propagation directionand physical dimensions of the slots All these methodsultimately changed the value of reactance of resonators andcoupling of the EM field Here we have demonstrated threepossible methods to tune the response (i) pose of slot (ii)length of slot (iii) width of slot For demonstration andanalysis purpose onlywe applied the above tuningmethods tothe first slot These methods can also be applicable for otherremaining slots Figure 8(a) demonstrates simulation resultof reflection coefficient obtained by changing the positionof first slot which was kept at 120582
1198922 distance with respect
to second slot in longitude direction It shows that whenwe move the slot position in positive longitude direction itimproves the value of return loss and increment in oppositedirection it reduces the value of return loss Figure 8(b)shows the simulation result with increasing the length of thefirst slot It decreases the values of inductance and increasesthe capacitance value Variation in length gave minor effecton a reflection coefficient value Similarly Figure 8(c) is theresult of reflection coefficient with the change in width of
1424mm4mm3376mm
1702mm
0508mm
2136mm
9mm 10mm30mm
Figure 9 2nd proposed structure contains I shape logarithmic slotsarray antenna
m3
m4
m5
m6
m7m8m9
m2 m10
m1
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
700 800 900 1000 1100 1200 1300 1400 1500600
Curve info
Setup1 sweep
Freq (GHz)
Name X Y
m1 77080m2 81210m3 84170m4 87660m5 92910m6 102010m7 104890m8 109930m9 118430m10 137490 minus124121
minus156759minus138911minus147592minus226325minus274168minus103236minus241340minus124315minus180066
S11 (dB)
S 11
(dB)
Figure 10 11987811plot for I shaped logarithmic slots array antenna
the first slot that tunes resonant frequency effectively and alsoproduces very sharp bandwidth
In the second proposed structure instead of takingrectangular shape slots longitudinal I shape is selected whichis shown in Figure 9 Spacing between two slots and centerdistance of last slots from the end boadsie wall are the same as1st proposed design In first I shape slot vertical height of theslot is 4mm and length of slot is 10mm which progressivelyincreases for other slots according to logarthmic nature
This structure is also simulated by using HFSS and itsreturn loss is shwon in Figure 10 This structure radiates atsix resonant frequencies one in C band (77 GHz) three inX band (812 841 876 929 102 1048 1099 1145 and
8 International Journal of Microwave Science and Technology
Y
Z
53483e + 00033392e + 00013301e + 000minus67903e minus 001minus26881e + 000minus46972e + 000minus67063e + 000minus87154e + 000minus10725e + 001minus12734e + 001minus14743e + 001minus16752e + 001minus18761e + 001minus20770e + 001minus22779e + 001minus24788e + 001minus26797e + 001
GainTotal (dB)
(a)
080
160
240
320
90
60
300
150
120
Curve inforETotal
Setup1 LastAdaptiveFreq = 71GHz Theta = 90degldquo ldquordquo rdquo
minus30
minus60
minus90
minus120
minus150minus180
(b)
Figure 11 (a) Gain plot and (b) radiation pattern for I shape logarithmic slots array antenna
1424mm 3376mm
1702mm
0508mm
9mm 10mm30mm
15mm 21mm
Figure 12 3rd proposed structure contains trapezoidal logarithmic slots array antenna
m2
m3
m4m5 m6
m7
m8m1
Curve info
Setup1 sweep
700 800 900 1000 1100 1200 1300 1400 1500600Freq (GHz)
minus3500
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
Name X Y
m1 67300m2 78400m3 103800m4 110700m5 114300m6 121400m7 128100m8 143600 minus183495
minus300236
minus181027minus163299
minus202328
minus270798
minus154970minus159939
S11 (dB)
S 11
(dB)
Figure 13 11987811plot for trapezoidal logarithmic slots array antenna
119 GHz) and two in Ku band (1395 and 145 GHz)The gainplot and radiation pattern for 67GHz frequency are shownin Figures 11(a) and 11(b) which shows that it generates gainof 5 dB which is half compared to first proposed structure
Third proposed structure contains trapezoidal logarith-mic slots array as shown in Figure 12 Distances of all the slots
m1 m2 m3 m4 m5 m6 m7 m8
700 800 900 1000 1100 1200 1300 1400 1500600Freq (GHz)
000500
100015002000250030003500
VSW
R(1)
Curve infoVSWR(1)
Setup1 sweep
Name X Ym1 67200 13759m2 78400 14037m3 103800 10926m4 110700 12157m5 114300 13601m6 121400 12842m7 128000 10823m8 143700 12861
Figure 14 VSWR of 3rd proposed trapezoidal logarithmic slotsarray antenna
are the same as 1st proposed design Simulated result of theproposed structure is shown in Figure 13 which shows higherreturn loss occurring at eight different frequencies two in Cband (67 and 754GHz) four in X band (1025 11 1143 and
International Journal of Microwave Science and Technology 9
10300e + 001
79774e + 000
33329e + 00056551e + 000
10107e + 000minus13115e + 000minus36337e + 000minus59560e + 000minus82782e + 000minus10600e + 001minus12923e + 001minus15245e + 001minus17567e + 001minus19889e + 001minus22211e + 001
minus26856e + 001
minus24534e + 001
GainTotal (dB)
Y
Z
(a)
Curve inforETotal
Setup1 LastAdaptiveFreq = 71GHz Theta = 90degldquo ldquordquo rdquo
minus30
minus90
minus120
minus150
minus180
minus60
200
400
600
800
90
60
300
150
120
(b)
Figure 15 (a) Gain plot and (b) radiation pattern for trapezoidal logarithmic slots array antenna
Figure 16 Fabricated model of logarithmic rectangular slots arrayantenna
5 10 15
minus30
minus25
minus20
minus15
minus10
minus5
0
Simulated S11 (dB)Measured S11 (dB)
Figure 17 11987811of logarithmic rectangular slots array antenna
1214GHz) and Ku band (1281 and 1436GHz) Its VSWR isshown in Figure 14Gain plot and radiation pattern are shownin Figures 15(a) and 15(b) respectively It gives more than10 dB gain at 67 GHz frequency
Simulated gainMeasured gain
00 30 60 90 120 150 180 210 240 270 300 360330
1
2
3
4
5
6
7
8
9
10
Figure 18 Gain of logarithmic rectangular slots array antenna
5 Measured Results
Logarithmic rectangular slots array antenna has been fabri-cated on Rogers RT Duroid 5880 high frequency substratewith a thickness of 0787mm relative permittivity of 22 andrelative permeability of 1 and loss tangent of 00009 The topside of the antenna has logarithmic slots and the other side isground planeThe photograph of fabricated antenna is shownin Figure 16
The antenna 11987811parameter and gain are measured using
the Vector Network Analyzer MVNA-8-350 with probe sta-tion The simulated and measured 119878
11parameter for antenna
is shown in Figure 17 A slight difference is observed between
10 International Journal of Microwave Science and Technology
Radiation efficiency
100
095
090
085
HFSSCurve info
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Radiation efficiency
Radiation efficiency
Setup1 LastAdaptiveFreq = 71GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Freq = 71GHz Theta = 10degldquo ldquordquo rdquo
Freq = 71GHz Theta = 20degldquo ldquordquo rdquo
Freq = 71GHz Theta = 50degldquo ldquordquo rdquo
Freq = 71GHz Theta = 40degldquo ldquordquo rdquo
Freq = 71GHz Theta = 60degldquo ldquordquo rdquo
Freq = 71GHz Theta = 30degldquo ldquordquo rdquo
(a)
Radiation efficiency
HFSS design2Curve info
096
092
088
084
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 10degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 20degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 50degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 40degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 60degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 30degldquo ldquordquo rdquo
(b)
Figure 19 Radiation efficiency of logarithmic rectangular slots array antenna in (a) C band and (b) X band
the measured value and simulated value The differencebetween the measured and simulated 119878
11of the antenna is
caused by the microstrip to SIW transitionThe simulated and measured gain of the antenna are
shown in Figure 18Themaximummeasured gain is also veryclose to 10 dB at 7GHz for the antenna which is max Themeasured result shows that the bandwidth of the antennacovers over 300MHz while the gain of the antenna is keptalmost constantwithin such awide bandwidth of the antennaSimulation results specify that metallic and dielectric lossesdo not have a substantial effect on the bandwidth andmatching condition of the antenna while they decrease themeasured gain of antenna by 05 dB The apparent differencebetween the simulation and measured gains might be dueto the calibration linked tolerance range of the antennareference in anechoic chamber
The radiation pattern of the antenna at resonant fre-quency is shown in Figure 18 The radiation pattern mea-surement is carried out in a conventional far field anechoicchamber which uses a V connector to connect the antennaDue to the size of the connector compared to the antenna therear radiation patterns were not incorporated in the resultsHowever the similar effects were observed in the simulationresults and most significantly the radiating behavior of theantenna is very similar to simulation results As shown inFigures 19(a) and 19(b) they represent the radiation efficiencyin C band and X band respectively which is 92 and 88
6 Observation and Discussion
From the simulation results we have observed the followingthings
(i) All the structure gives six or more than six resonantfrequencies in C band X band and Ku band
(ii) Gain generated by rectangular and trapezoidal log-arithmic slots array antenna is more than 10 dBcompared to I shape logarithmic slots array antenna
(iii) Isolation between two radiation bands ismuch higherin trapezoidal logarithmic slots array antenna andalso generates low leakage loss in stop band
(iv) Size of entire proposed antennas is compact com-pared to traditional antennas which are proposed forhigh gain applications
(v) Bandwidth produced by all the antennas at resonantfrequencies is more than 100MHz
7 Conclusion
From the design and simulation results it is clear that allthe antennas are compact in size and they are capable togenerate multiband frequencies which are very importantfactors for the proposed design process of antennas Antennasbased on SIW technology have been proposed in this paper
International Journal of Microwave Science and Technology 11
These structures can find many applications in C band and Xband for radar and remote sensingmechanism and are one ofthe major areas in docking satellite where communication isdone in C band while ranging is carried out in X band So thisantenna fulfilled both requirements instead of using two dif-ferent antennas Significant increment of gain parameter hasbeen obtained for introduction of more number and varietyof shapes of slots Compared to identical slots logarithmicslots give higher gain The effect has been extensively studiedunlike any other recent publication in this fieldThe structureis very simple and development of the prototype is easy inpresence of advanced PCB fabrication technology
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] P N Richardson and H Y Lee ldquoDesign and analysis of slottedwaveguide arraysrdquoMicrowave Journal vol 31 pp 109ndash125 1988
[2] S Ravish A Patel V V Dwivedi and H B Pandya ldquoDesigndevelopment and fabrication of post coupled band pass waveg-uide filter at 112 GHz for radiometerrdquo Microwave Journal vol51 2008
[3] A Patel Y Kosta N Chhasatia and K Pandya ldquoMultiple bandwaveguide based microwave resonatorrdquo in Proceedings of the1st International Conference on Advances in Engineering Scienceand Management (ICAESM rsquo12) pp 84ndash87 NagapattinamIndia March 2012
[4] S R Rengarajan ldquoCompound radiating slots in a broad wall ofa rectangular waveguiderdquo IEEE Transactions on Antennas andPropagation vol 37 no 9 pp 1116ndash1123 1989
[5] A Patel and Y P Kosta ldquoMultiple-band waveguide based band-stop filterrdquo International Journal of Applied Electromagnetics andMechanics vol 47 no 2 pp 563ndash581 2015
[6] S Fallahzadeh H Bahrami and M Tayarani ldquoA novel dual-band bandstop waveguide filter using split ring resonatorsrdquoProgress in Electromagnetics Research Letters vol 12 pp 133ndash139 2009
[7] I Ohta Y Yumita K Toda and M Kishihara ldquoCruciformdirectional couplers in H-plane rectangular waveguiderdquo in Pro-ceedings of the Asia-Pacific Microwave Conference (APMC rsquo05)vol 2 December 2005
[8] A Patel Y Kosta N Chhasatia and F Raval ldquoDesign andfabrication of microwave waveguide resonator with improvedcharacteristic responserdquo European Journal of Scientific Researchvol 102 no 2 pp 163ndash174 2013
[9] R S Elliott and L A Kurtz ldquoThe design of small slot arraysrdquoIEEE Transactions on Antennas and Propagation vol 26 no 2pp 214ndash219 1978
[10] R S Elliott ldquoAn improved design procedure for small arrays ofshunt slotsrdquo IEEE Transactions on Antennas and Propagationvol 31 no 1 pp 48ndash53 1983
[11] A F Stevenson ldquoTheory of slots in rectangular wave-guidesrdquoJournal of Applied Physics vol 19 pp 24ndash38 1948
[12] W Coburn M Litz J Miletta N Tesny L Dilks and B KingldquoA slotted-waveguide array for high-power microwave trans-missionrdquo Progress Report for FY 2000 US Army ResearchLaboratory Adelphi Md USA 2001
[13] F Raval Y P Kosta J Makwana and A V Patel ldquoDesign amp im-plementation of reduced size microstrip patch antenna withmetamaterial defected ground planerdquo in Proceedings of the 2ndInternational Conference on Communication and Signal Proc-essing (ICCSP rsquo13) pp 186ndash190 IEEE Melmaruvathur IndiaApril 2013
[14] M Kahrizi T K Sarkar and Z AMaricevic ldquoAnalysis of a wideradiating slot in the ground plane of a microstrip linerdquo IEEETransactions onMicrowaveTheory and Techniques vol 41 no 1pp 29ndash37 1993
[15] J Galejst ldquoAdmittance of a rectangular slot which is backed bya rectangular cavityrdquo IEEE Transactions on Antennas and Prop-agation vol 11 no 2 pp 119ndash126 1963
[16] K-LWongCompact andBroadbandMicrostripAntennas JohnWiley amp Sons New York NY USA 2002
[17] W-S Chen ldquoSingle-feed dual-frequency rectangularmicrostripantenna with square slotrdquo Electronics Letters vol 34 no 3 pp231ndash232 1998
[18] D Busuioc M Shahabadi A Borji G Shaker and S Safavi-Naeini ldquoSubstrate integrated waveguide antenna feedmdashdesignmethodology and validationrdquo in Proceedings of the IEEE Anten-nas and Propagation Society International Symposium (AP-Srsquo07) pp 2666ndash2669 Honolulu Hawaii USA June 2007
[19] H Kumar R Jadhav and S Ranade ldquoA review on substrateintegrated waveguide and its microstrip interconnectrdquo Journalof Electronics and Communication Engineering vol 3 no 5 pp36ndash40 2012
[20] M Bozzi F XuDDeslandes andKWu ldquoModeling and designconsiderations for substrate integrated waveguide circuits andcomponentsrdquo in Proceedings of the 8th International Conferenceon Telecommunications in Modern Satellite Cable and Broad-casting Services (TELSIKS rsquo07) pp P-7ndashP-16 IEEE Nis SerbiaSeptember 2007
[21] S Moitra A Mukhopadhyay and A Bhattacharjee ldquoKu-bandsubstrate integrated waveguide (SIW) slot array antenna fornext generation networksrdquo Global Journal of Computer Scienceand Technology E Network Web amp Security vol 13 no 5 pp11ndash16 2013
[22] A J Farrall and P R Young ldquoIntegrated waveguide slot anten-nasrdquo Electronics Letters vol 40 no 16 pp 974ndash975 2004
[23] D PozarMicrowave Engineering JohnWiley amp Sons HobokenNJ USA 3rd edition 2005
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
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Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
6 International Journal of Microwave Science and Technology
625 825 1025 1225 1425
minus35
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo63mmrdquob1 = ldquo1856mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1256mmrdquoa1f = ldquo425mmrdquoS11 (dB)
S11 (dB)
S11 (dB)
(a)
625 825 1025 1225 1425
minus45
minus40
minus35
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo73mmrdquob1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo53mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo425mmrdquoS11 (dB)
S11 (dB)
S11 (dB)
(b)
625 825 1025 1225 1425
minus30
minus25
minus20
minus15
minus10
minus5
0
b1f = ldquo63mmrdquob1 = ldquo1556mmrdquoa1f = ldquo525mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo325mmrdquo
b1f = ldquo63mmrdquo
b1 = ldquo1556mmrdquoa1f = ldquo225mmrdquoS11 (dB) S11 (dB)
S11 (dB)
(c)
Figure 8 (a) 11987811of logarithmic rectangular slots array antenna with respect to variations in 1st slot position (b) 119878
11of logarithmic rectangular
slots array antennawith respect to variations in 1st slot position (c) 11987811of logarithmic rectangular slots array antennawith respect to variations
in width of 1st slot
International Journal of Microwave Science and Technology 7
Table 2 Calculated parameters
Parameter 119891
119888119886
1015840
119863 119875 119886
119904120576
119903120582
119888120582
119892119908 119886
119905119897
119908119897
119905
Value 71 GHz 142mm 9mm 10mm 2276mm 22 4225mm 2848mm 5504mm 15mm 170mm 30mm
Table 3 Summaries of simulated parameters
Resonant frequency Gain in dB Bandwidth in MHz VSWR Peak return loss in dB705GHz 1085 100 105 minus31431085GHz 75 200 119 minus2100119 GHz 71 250 113 minus2371146GHz 69 400 1097 minus2664
As shown in Figure 4 it contains six rectangular slotsarray whose longitudinal length is varied according to log-arithmic manner We are keeping center-to-center distancebetween two slots as 1424mm (120582
1198922) and center of last slot
to broadside wall as 2136mmThe structure has been simulated using HFSS (High Fre-
quency Structure Simulator) and it generates return lossshown in Figure 5 As shown in Figure 5 the structure gen-erates six resonant frequencies one in C band (705GHz)three in X band (102 1055 and 115 GHz) and two inKu band (128 and 146GHz) respectively These results aretotally expected since the proposed antenna is composedof different resonant slot lengths providing the multibandperformance At all the resonant frequencies VSWR is alsogood which is shown in Figure 6 One of the extraordinaryperformances generated by this structure is shown in Figure 7which represents the gain value that is more than 10 dBin single layer and single array combination compared toother traditional antennas having multilayer and 2 to 3arrays for achieving higher gain Various gain and radiationpatterns of the proposed logarithmic slots array of antennafor different resonant frequencies are shown in Figure 6 Allthe simulation results are summarized in Table 3
It is possible to tune the frequency by changing the geo-metrical position with respect to wave propagation directionand physical dimensions of the slots All these methodsultimately changed the value of reactance of resonators andcoupling of the EM field Here we have demonstrated threepossible methods to tune the response (i) pose of slot (ii)length of slot (iii) width of slot For demonstration andanalysis purpose onlywe applied the above tuningmethods tothe first slot These methods can also be applicable for otherremaining slots Figure 8(a) demonstrates simulation resultof reflection coefficient obtained by changing the positionof first slot which was kept at 120582
1198922 distance with respect
to second slot in longitude direction It shows that whenwe move the slot position in positive longitude direction itimproves the value of return loss and increment in oppositedirection it reduces the value of return loss Figure 8(b)shows the simulation result with increasing the length of thefirst slot It decreases the values of inductance and increasesthe capacitance value Variation in length gave minor effecton a reflection coefficient value Similarly Figure 8(c) is theresult of reflection coefficient with the change in width of
1424mm4mm3376mm
1702mm
0508mm
2136mm
9mm 10mm30mm
Figure 9 2nd proposed structure contains I shape logarithmic slotsarray antenna
m3
m4
m5
m6
m7m8m9
m2 m10
m1
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
700 800 900 1000 1100 1200 1300 1400 1500600
Curve info
Setup1 sweep
Freq (GHz)
Name X Y
m1 77080m2 81210m3 84170m4 87660m5 92910m6 102010m7 104890m8 109930m9 118430m10 137490 minus124121
minus156759minus138911minus147592minus226325minus274168minus103236minus241340minus124315minus180066
S11 (dB)
S 11
(dB)
Figure 10 11987811plot for I shaped logarithmic slots array antenna
the first slot that tunes resonant frequency effectively and alsoproduces very sharp bandwidth
In the second proposed structure instead of takingrectangular shape slots longitudinal I shape is selected whichis shown in Figure 9 Spacing between two slots and centerdistance of last slots from the end boadsie wall are the same as1st proposed design In first I shape slot vertical height of theslot is 4mm and length of slot is 10mm which progressivelyincreases for other slots according to logarthmic nature
This structure is also simulated by using HFSS and itsreturn loss is shwon in Figure 10 This structure radiates atsix resonant frequencies one in C band (77 GHz) three inX band (812 841 876 929 102 1048 1099 1145 and
8 International Journal of Microwave Science and Technology
Y
Z
53483e + 00033392e + 00013301e + 000minus67903e minus 001minus26881e + 000minus46972e + 000minus67063e + 000minus87154e + 000minus10725e + 001minus12734e + 001minus14743e + 001minus16752e + 001minus18761e + 001minus20770e + 001minus22779e + 001minus24788e + 001minus26797e + 001
GainTotal (dB)
(a)
080
160
240
320
90
60
300
150
120
Curve inforETotal
Setup1 LastAdaptiveFreq = 71GHz Theta = 90degldquo ldquordquo rdquo
minus30
minus60
minus90
minus120
minus150minus180
(b)
Figure 11 (a) Gain plot and (b) radiation pattern for I shape logarithmic slots array antenna
1424mm 3376mm
1702mm
0508mm
9mm 10mm30mm
15mm 21mm
Figure 12 3rd proposed structure contains trapezoidal logarithmic slots array antenna
m2
m3
m4m5 m6
m7
m8m1
Curve info
Setup1 sweep
700 800 900 1000 1100 1200 1300 1400 1500600Freq (GHz)
minus3500
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
Name X Y
m1 67300m2 78400m3 103800m4 110700m5 114300m6 121400m7 128100m8 143600 minus183495
minus300236
minus181027minus163299
minus202328
minus270798
minus154970minus159939
S11 (dB)
S 11
(dB)
Figure 13 11987811plot for trapezoidal logarithmic slots array antenna
119 GHz) and two in Ku band (1395 and 145 GHz)The gainplot and radiation pattern for 67GHz frequency are shownin Figures 11(a) and 11(b) which shows that it generates gainof 5 dB which is half compared to first proposed structure
Third proposed structure contains trapezoidal logarith-mic slots array as shown in Figure 12 Distances of all the slots
m1 m2 m3 m4 m5 m6 m7 m8
700 800 900 1000 1100 1200 1300 1400 1500600Freq (GHz)
000500
100015002000250030003500
VSW
R(1)
Curve infoVSWR(1)
Setup1 sweep
Name X Ym1 67200 13759m2 78400 14037m3 103800 10926m4 110700 12157m5 114300 13601m6 121400 12842m7 128000 10823m8 143700 12861
Figure 14 VSWR of 3rd proposed trapezoidal logarithmic slotsarray antenna
are the same as 1st proposed design Simulated result of theproposed structure is shown in Figure 13 which shows higherreturn loss occurring at eight different frequencies two in Cband (67 and 754GHz) four in X band (1025 11 1143 and
International Journal of Microwave Science and Technology 9
10300e + 001
79774e + 000
33329e + 00056551e + 000
10107e + 000minus13115e + 000minus36337e + 000minus59560e + 000minus82782e + 000minus10600e + 001minus12923e + 001minus15245e + 001minus17567e + 001minus19889e + 001minus22211e + 001
minus26856e + 001
minus24534e + 001
GainTotal (dB)
Y
Z
(a)
Curve inforETotal
Setup1 LastAdaptiveFreq = 71GHz Theta = 90degldquo ldquordquo rdquo
minus30
minus90
minus120
minus150
minus180
minus60
200
400
600
800
90
60
300
150
120
(b)
Figure 15 (a) Gain plot and (b) radiation pattern for trapezoidal logarithmic slots array antenna
Figure 16 Fabricated model of logarithmic rectangular slots arrayantenna
5 10 15
minus30
minus25
minus20
minus15
minus10
minus5
0
Simulated S11 (dB)Measured S11 (dB)
Figure 17 11987811of logarithmic rectangular slots array antenna
1214GHz) and Ku band (1281 and 1436GHz) Its VSWR isshown in Figure 14Gain plot and radiation pattern are shownin Figures 15(a) and 15(b) respectively It gives more than10 dB gain at 67 GHz frequency
Simulated gainMeasured gain
00 30 60 90 120 150 180 210 240 270 300 360330
1
2
3
4
5
6
7
8
9
10
Figure 18 Gain of logarithmic rectangular slots array antenna
5 Measured Results
Logarithmic rectangular slots array antenna has been fabri-cated on Rogers RT Duroid 5880 high frequency substratewith a thickness of 0787mm relative permittivity of 22 andrelative permeability of 1 and loss tangent of 00009 The topside of the antenna has logarithmic slots and the other side isground planeThe photograph of fabricated antenna is shownin Figure 16
The antenna 11987811parameter and gain are measured using
the Vector Network Analyzer MVNA-8-350 with probe sta-tion The simulated and measured 119878
11parameter for antenna
is shown in Figure 17 A slight difference is observed between
10 International Journal of Microwave Science and Technology
Radiation efficiency
100
095
090
085
HFSSCurve info
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Radiation efficiency
Radiation efficiency
Setup1 LastAdaptiveFreq = 71GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Freq = 71GHz Theta = 10degldquo ldquordquo rdquo
Freq = 71GHz Theta = 20degldquo ldquordquo rdquo
Freq = 71GHz Theta = 50degldquo ldquordquo rdquo
Freq = 71GHz Theta = 40degldquo ldquordquo rdquo
Freq = 71GHz Theta = 60degldquo ldquordquo rdquo
Freq = 71GHz Theta = 30degldquo ldquordquo rdquo
(a)
Radiation efficiency
HFSS design2Curve info
096
092
088
084
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 10degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 20degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 50degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 40degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 60degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 30degldquo ldquordquo rdquo
(b)
Figure 19 Radiation efficiency of logarithmic rectangular slots array antenna in (a) C band and (b) X band
the measured value and simulated value The differencebetween the measured and simulated 119878
11of the antenna is
caused by the microstrip to SIW transitionThe simulated and measured gain of the antenna are
shown in Figure 18Themaximummeasured gain is also veryclose to 10 dB at 7GHz for the antenna which is max Themeasured result shows that the bandwidth of the antennacovers over 300MHz while the gain of the antenna is keptalmost constantwithin such awide bandwidth of the antennaSimulation results specify that metallic and dielectric lossesdo not have a substantial effect on the bandwidth andmatching condition of the antenna while they decrease themeasured gain of antenna by 05 dB The apparent differencebetween the simulation and measured gains might be dueto the calibration linked tolerance range of the antennareference in anechoic chamber
The radiation pattern of the antenna at resonant fre-quency is shown in Figure 18 The radiation pattern mea-surement is carried out in a conventional far field anechoicchamber which uses a V connector to connect the antennaDue to the size of the connector compared to the antenna therear radiation patterns were not incorporated in the resultsHowever the similar effects were observed in the simulationresults and most significantly the radiating behavior of theantenna is very similar to simulation results As shown inFigures 19(a) and 19(b) they represent the radiation efficiencyin C band and X band respectively which is 92 and 88
6 Observation and Discussion
From the simulation results we have observed the followingthings
(i) All the structure gives six or more than six resonantfrequencies in C band X band and Ku band
(ii) Gain generated by rectangular and trapezoidal log-arithmic slots array antenna is more than 10 dBcompared to I shape logarithmic slots array antenna
(iii) Isolation between two radiation bands ismuch higherin trapezoidal logarithmic slots array antenna andalso generates low leakage loss in stop band
(iv) Size of entire proposed antennas is compact com-pared to traditional antennas which are proposed forhigh gain applications
(v) Bandwidth produced by all the antennas at resonantfrequencies is more than 100MHz
7 Conclusion
From the design and simulation results it is clear that allthe antennas are compact in size and they are capable togenerate multiband frequencies which are very importantfactors for the proposed design process of antennas Antennasbased on SIW technology have been proposed in this paper
International Journal of Microwave Science and Technology 11
These structures can find many applications in C band and Xband for radar and remote sensingmechanism and are one ofthe major areas in docking satellite where communication isdone in C band while ranging is carried out in X band So thisantenna fulfilled both requirements instead of using two dif-ferent antennas Significant increment of gain parameter hasbeen obtained for introduction of more number and varietyof shapes of slots Compared to identical slots logarithmicslots give higher gain The effect has been extensively studiedunlike any other recent publication in this fieldThe structureis very simple and development of the prototype is easy inpresence of advanced PCB fabrication technology
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] P N Richardson and H Y Lee ldquoDesign and analysis of slottedwaveguide arraysrdquoMicrowave Journal vol 31 pp 109ndash125 1988
[2] S Ravish A Patel V V Dwivedi and H B Pandya ldquoDesigndevelopment and fabrication of post coupled band pass waveg-uide filter at 112 GHz for radiometerrdquo Microwave Journal vol51 2008
[3] A Patel Y Kosta N Chhasatia and K Pandya ldquoMultiple bandwaveguide based microwave resonatorrdquo in Proceedings of the1st International Conference on Advances in Engineering Scienceand Management (ICAESM rsquo12) pp 84ndash87 NagapattinamIndia March 2012
[4] S R Rengarajan ldquoCompound radiating slots in a broad wall ofa rectangular waveguiderdquo IEEE Transactions on Antennas andPropagation vol 37 no 9 pp 1116ndash1123 1989
[5] A Patel and Y P Kosta ldquoMultiple-band waveguide based band-stop filterrdquo International Journal of Applied Electromagnetics andMechanics vol 47 no 2 pp 563ndash581 2015
[6] S Fallahzadeh H Bahrami and M Tayarani ldquoA novel dual-band bandstop waveguide filter using split ring resonatorsrdquoProgress in Electromagnetics Research Letters vol 12 pp 133ndash139 2009
[7] I Ohta Y Yumita K Toda and M Kishihara ldquoCruciformdirectional couplers in H-plane rectangular waveguiderdquo in Pro-ceedings of the Asia-Pacific Microwave Conference (APMC rsquo05)vol 2 December 2005
[8] A Patel Y Kosta N Chhasatia and F Raval ldquoDesign andfabrication of microwave waveguide resonator with improvedcharacteristic responserdquo European Journal of Scientific Researchvol 102 no 2 pp 163ndash174 2013
[9] R S Elliott and L A Kurtz ldquoThe design of small slot arraysrdquoIEEE Transactions on Antennas and Propagation vol 26 no 2pp 214ndash219 1978
[10] R S Elliott ldquoAn improved design procedure for small arrays ofshunt slotsrdquo IEEE Transactions on Antennas and Propagationvol 31 no 1 pp 48ndash53 1983
[11] A F Stevenson ldquoTheory of slots in rectangular wave-guidesrdquoJournal of Applied Physics vol 19 pp 24ndash38 1948
[12] W Coburn M Litz J Miletta N Tesny L Dilks and B KingldquoA slotted-waveguide array for high-power microwave trans-missionrdquo Progress Report for FY 2000 US Army ResearchLaboratory Adelphi Md USA 2001
[13] F Raval Y P Kosta J Makwana and A V Patel ldquoDesign amp im-plementation of reduced size microstrip patch antenna withmetamaterial defected ground planerdquo in Proceedings of the 2ndInternational Conference on Communication and Signal Proc-essing (ICCSP rsquo13) pp 186ndash190 IEEE Melmaruvathur IndiaApril 2013
[14] M Kahrizi T K Sarkar and Z AMaricevic ldquoAnalysis of a wideradiating slot in the ground plane of a microstrip linerdquo IEEETransactions onMicrowaveTheory and Techniques vol 41 no 1pp 29ndash37 1993
[15] J Galejst ldquoAdmittance of a rectangular slot which is backed bya rectangular cavityrdquo IEEE Transactions on Antennas and Prop-agation vol 11 no 2 pp 119ndash126 1963
[16] K-LWongCompact andBroadbandMicrostripAntennas JohnWiley amp Sons New York NY USA 2002
[17] W-S Chen ldquoSingle-feed dual-frequency rectangularmicrostripantenna with square slotrdquo Electronics Letters vol 34 no 3 pp231ndash232 1998
[18] D Busuioc M Shahabadi A Borji G Shaker and S Safavi-Naeini ldquoSubstrate integrated waveguide antenna feedmdashdesignmethodology and validationrdquo in Proceedings of the IEEE Anten-nas and Propagation Society International Symposium (AP-Srsquo07) pp 2666ndash2669 Honolulu Hawaii USA June 2007
[19] H Kumar R Jadhav and S Ranade ldquoA review on substrateintegrated waveguide and its microstrip interconnectrdquo Journalof Electronics and Communication Engineering vol 3 no 5 pp36ndash40 2012
[20] M Bozzi F XuDDeslandes andKWu ldquoModeling and designconsiderations for substrate integrated waveguide circuits andcomponentsrdquo in Proceedings of the 8th International Conferenceon Telecommunications in Modern Satellite Cable and Broad-casting Services (TELSIKS rsquo07) pp P-7ndashP-16 IEEE Nis SerbiaSeptember 2007
[21] S Moitra A Mukhopadhyay and A Bhattacharjee ldquoKu-bandsubstrate integrated waveguide (SIW) slot array antenna fornext generation networksrdquo Global Journal of Computer Scienceand Technology E Network Web amp Security vol 13 no 5 pp11ndash16 2013
[22] A J Farrall and P R Young ldquoIntegrated waveguide slot anten-nasrdquo Electronics Letters vol 40 no 16 pp 974ndash975 2004
[23] D PozarMicrowave Engineering JohnWiley amp Sons HobokenNJ USA 3rd edition 2005
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
International Journal of Microwave Science and Technology 7
Table 2 Calculated parameters
Parameter 119891
119888119886
1015840
119863 119875 119886
119904120576
119903120582
119888120582
119892119908 119886
119905119897
119908119897
119905
Value 71 GHz 142mm 9mm 10mm 2276mm 22 4225mm 2848mm 5504mm 15mm 170mm 30mm
Table 3 Summaries of simulated parameters
Resonant frequency Gain in dB Bandwidth in MHz VSWR Peak return loss in dB705GHz 1085 100 105 minus31431085GHz 75 200 119 minus2100119 GHz 71 250 113 minus2371146GHz 69 400 1097 minus2664
As shown in Figure 4 it contains six rectangular slotsarray whose longitudinal length is varied according to log-arithmic manner We are keeping center-to-center distancebetween two slots as 1424mm (120582
1198922) and center of last slot
to broadside wall as 2136mmThe structure has been simulated using HFSS (High Fre-
quency Structure Simulator) and it generates return lossshown in Figure 5 As shown in Figure 5 the structure gen-erates six resonant frequencies one in C band (705GHz)three in X band (102 1055 and 115 GHz) and two inKu band (128 and 146GHz) respectively These results aretotally expected since the proposed antenna is composedof different resonant slot lengths providing the multibandperformance At all the resonant frequencies VSWR is alsogood which is shown in Figure 6 One of the extraordinaryperformances generated by this structure is shown in Figure 7which represents the gain value that is more than 10 dBin single layer and single array combination compared toother traditional antennas having multilayer and 2 to 3arrays for achieving higher gain Various gain and radiationpatterns of the proposed logarithmic slots array of antennafor different resonant frequencies are shown in Figure 6 Allthe simulation results are summarized in Table 3
It is possible to tune the frequency by changing the geo-metrical position with respect to wave propagation directionand physical dimensions of the slots All these methodsultimately changed the value of reactance of resonators andcoupling of the EM field Here we have demonstrated threepossible methods to tune the response (i) pose of slot (ii)length of slot (iii) width of slot For demonstration andanalysis purpose onlywe applied the above tuningmethods tothe first slot These methods can also be applicable for otherremaining slots Figure 8(a) demonstrates simulation resultof reflection coefficient obtained by changing the positionof first slot which was kept at 120582
1198922 distance with respect
to second slot in longitude direction It shows that whenwe move the slot position in positive longitude direction itimproves the value of return loss and increment in oppositedirection it reduces the value of return loss Figure 8(b)shows the simulation result with increasing the length of thefirst slot It decreases the values of inductance and increasesthe capacitance value Variation in length gave minor effecton a reflection coefficient value Similarly Figure 8(c) is theresult of reflection coefficient with the change in width of
1424mm4mm3376mm
1702mm
0508mm
2136mm
9mm 10mm30mm
Figure 9 2nd proposed structure contains I shape logarithmic slotsarray antenna
m3
m4
m5
m6
m7m8m9
m2 m10
m1
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
700 800 900 1000 1100 1200 1300 1400 1500600
Curve info
Setup1 sweep
Freq (GHz)
Name X Y
m1 77080m2 81210m3 84170m4 87660m5 92910m6 102010m7 104890m8 109930m9 118430m10 137490 minus124121
minus156759minus138911minus147592minus226325minus274168minus103236minus241340minus124315minus180066
S11 (dB)
S 11
(dB)
Figure 10 11987811plot for I shaped logarithmic slots array antenna
the first slot that tunes resonant frequency effectively and alsoproduces very sharp bandwidth
In the second proposed structure instead of takingrectangular shape slots longitudinal I shape is selected whichis shown in Figure 9 Spacing between two slots and centerdistance of last slots from the end boadsie wall are the same as1st proposed design In first I shape slot vertical height of theslot is 4mm and length of slot is 10mm which progressivelyincreases for other slots according to logarthmic nature
This structure is also simulated by using HFSS and itsreturn loss is shwon in Figure 10 This structure radiates atsix resonant frequencies one in C band (77 GHz) three inX band (812 841 876 929 102 1048 1099 1145 and
8 International Journal of Microwave Science and Technology
Y
Z
53483e + 00033392e + 00013301e + 000minus67903e minus 001minus26881e + 000minus46972e + 000minus67063e + 000minus87154e + 000minus10725e + 001minus12734e + 001minus14743e + 001minus16752e + 001minus18761e + 001minus20770e + 001minus22779e + 001minus24788e + 001minus26797e + 001
GainTotal (dB)
(a)
080
160
240
320
90
60
300
150
120
Curve inforETotal
Setup1 LastAdaptiveFreq = 71GHz Theta = 90degldquo ldquordquo rdquo
minus30
minus60
minus90
minus120
minus150minus180
(b)
Figure 11 (a) Gain plot and (b) radiation pattern for I shape logarithmic slots array antenna
1424mm 3376mm
1702mm
0508mm
9mm 10mm30mm
15mm 21mm
Figure 12 3rd proposed structure contains trapezoidal logarithmic slots array antenna
m2
m3
m4m5 m6
m7
m8m1
Curve info
Setup1 sweep
700 800 900 1000 1100 1200 1300 1400 1500600Freq (GHz)
minus3500
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
Name X Y
m1 67300m2 78400m3 103800m4 110700m5 114300m6 121400m7 128100m8 143600 minus183495
minus300236
minus181027minus163299
minus202328
minus270798
minus154970minus159939
S11 (dB)
S 11
(dB)
Figure 13 11987811plot for trapezoidal logarithmic slots array antenna
119 GHz) and two in Ku band (1395 and 145 GHz)The gainplot and radiation pattern for 67GHz frequency are shownin Figures 11(a) and 11(b) which shows that it generates gainof 5 dB which is half compared to first proposed structure
Third proposed structure contains trapezoidal logarith-mic slots array as shown in Figure 12 Distances of all the slots
m1 m2 m3 m4 m5 m6 m7 m8
700 800 900 1000 1100 1200 1300 1400 1500600Freq (GHz)
000500
100015002000250030003500
VSW
R(1)
Curve infoVSWR(1)
Setup1 sweep
Name X Ym1 67200 13759m2 78400 14037m3 103800 10926m4 110700 12157m5 114300 13601m6 121400 12842m7 128000 10823m8 143700 12861
Figure 14 VSWR of 3rd proposed trapezoidal logarithmic slotsarray antenna
are the same as 1st proposed design Simulated result of theproposed structure is shown in Figure 13 which shows higherreturn loss occurring at eight different frequencies two in Cband (67 and 754GHz) four in X band (1025 11 1143 and
International Journal of Microwave Science and Technology 9
10300e + 001
79774e + 000
33329e + 00056551e + 000
10107e + 000minus13115e + 000minus36337e + 000minus59560e + 000minus82782e + 000minus10600e + 001minus12923e + 001minus15245e + 001minus17567e + 001minus19889e + 001minus22211e + 001
minus26856e + 001
minus24534e + 001
GainTotal (dB)
Y
Z
(a)
Curve inforETotal
Setup1 LastAdaptiveFreq = 71GHz Theta = 90degldquo ldquordquo rdquo
minus30
minus90
minus120
minus150
minus180
minus60
200
400
600
800
90
60
300
150
120
(b)
Figure 15 (a) Gain plot and (b) radiation pattern for trapezoidal logarithmic slots array antenna
Figure 16 Fabricated model of logarithmic rectangular slots arrayantenna
5 10 15
minus30
minus25
minus20
minus15
minus10
minus5
0
Simulated S11 (dB)Measured S11 (dB)
Figure 17 11987811of logarithmic rectangular slots array antenna
1214GHz) and Ku band (1281 and 1436GHz) Its VSWR isshown in Figure 14Gain plot and radiation pattern are shownin Figures 15(a) and 15(b) respectively It gives more than10 dB gain at 67 GHz frequency
Simulated gainMeasured gain
00 30 60 90 120 150 180 210 240 270 300 360330
1
2
3
4
5
6
7
8
9
10
Figure 18 Gain of logarithmic rectangular slots array antenna
5 Measured Results
Logarithmic rectangular slots array antenna has been fabri-cated on Rogers RT Duroid 5880 high frequency substratewith a thickness of 0787mm relative permittivity of 22 andrelative permeability of 1 and loss tangent of 00009 The topside of the antenna has logarithmic slots and the other side isground planeThe photograph of fabricated antenna is shownin Figure 16
The antenna 11987811parameter and gain are measured using
the Vector Network Analyzer MVNA-8-350 with probe sta-tion The simulated and measured 119878
11parameter for antenna
is shown in Figure 17 A slight difference is observed between
10 International Journal of Microwave Science and Technology
Radiation efficiency
100
095
090
085
HFSSCurve info
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Radiation efficiency
Radiation efficiency
Setup1 LastAdaptiveFreq = 71GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Freq = 71GHz Theta = 10degldquo ldquordquo rdquo
Freq = 71GHz Theta = 20degldquo ldquordquo rdquo
Freq = 71GHz Theta = 50degldquo ldquordquo rdquo
Freq = 71GHz Theta = 40degldquo ldquordquo rdquo
Freq = 71GHz Theta = 60degldquo ldquordquo rdquo
Freq = 71GHz Theta = 30degldquo ldquordquo rdquo
(a)
Radiation efficiency
HFSS design2Curve info
096
092
088
084
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 10degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 20degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 50degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 40degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 60degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 30degldquo ldquordquo rdquo
(b)
Figure 19 Radiation efficiency of logarithmic rectangular slots array antenna in (a) C band and (b) X band
the measured value and simulated value The differencebetween the measured and simulated 119878
11of the antenna is
caused by the microstrip to SIW transitionThe simulated and measured gain of the antenna are
shown in Figure 18Themaximummeasured gain is also veryclose to 10 dB at 7GHz for the antenna which is max Themeasured result shows that the bandwidth of the antennacovers over 300MHz while the gain of the antenna is keptalmost constantwithin such awide bandwidth of the antennaSimulation results specify that metallic and dielectric lossesdo not have a substantial effect on the bandwidth andmatching condition of the antenna while they decrease themeasured gain of antenna by 05 dB The apparent differencebetween the simulation and measured gains might be dueto the calibration linked tolerance range of the antennareference in anechoic chamber
The radiation pattern of the antenna at resonant fre-quency is shown in Figure 18 The radiation pattern mea-surement is carried out in a conventional far field anechoicchamber which uses a V connector to connect the antennaDue to the size of the connector compared to the antenna therear radiation patterns were not incorporated in the resultsHowever the similar effects were observed in the simulationresults and most significantly the radiating behavior of theantenna is very similar to simulation results As shown inFigures 19(a) and 19(b) they represent the radiation efficiencyin C band and X band respectively which is 92 and 88
6 Observation and Discussion
From the simulation results we have observed the followingthings
(i) All the structure gives six or more than six resonantfrequencies in C band X band and Ku band
(ii) Gain generated by rectangular and trapezoidal log-arithmic slots array antenna is more than 10 dBcompared to I shape logarithmic slots array antenna
(iii) Isolation between two radiation bands ismuch higherin trapezoidal logarithmic slots array antenna andalso generates low leakage loss in stop band
(iv) Size of entire proposed antennas is compact com-pared to traditional antennas which are proposed forhigh gain applications
(v) Bandwidth produced by all the antennas at resonantfrequencies is more than 100MHz
7 Conclusion
From the design and simulation results it is clear that allthe antennas are compact in size and they are capable togenerate multiband frequencies which are very importantfactors for the proposed design process of antennas Antennasbased on SIW technology have been proposed in this paper
International Journal of Microwave Science and Technology 11
These structures can find many applications in C band and Xband for radar and remote sensingmechanism and are one ofthe major areas in docking satellite where communication isdone in C band while ranging is carried out in X band So thisantenna fulfilled both requirements instead of using two dif-ferent antennas Significant increment of gain parameter hasbeen obtained for introduction of more number and varietyof shapes of slots Compared to identical slots logarithmicslots give higher gain The effect has been extensively studiedunlike any other recent publication in this fieldThe structureis very simple and development of the prototype is easy inpresence of advanced PCB fabrication technology
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] P N Richardson and H Y Lee ldquoDesign and analysis of slottedwaveguide arraysrdquoMicrowave Journal vol 31 pp 109ndash125 1988
[2] S Ravish A Patel V V Dwivedi and H B Pandya ldquoDesigndevelopment and fabrication of post coupled band pass waveg-uide filter at 112 GHz for radiometerrdquo Microwave Journal vol51 2008
[3] A Patel Y Kosta N Chhasatia and K Pandya ldquoMultiple bandwaveguide based microwave resonatorrdquo in Proceedings of the1st International Conference on Advances in Engineering Scienceand Management (ICAESM rsquo12) pp 84ndash87 NagapattinamIndia March 2012
[4] S R Rengarajan ldquoCompound radiating slots in a broad wall ofa rectangular waveguiderdquo IEEE Transactions on Antennas andPropagation vol 37 no 9 pp 1116ndash1123 1989
[5] A Patel and Y P Kosta ldquoMultiple-band waveguide based band-stop filterrdquo International Journal of Applied Electromagnetics andMechanics vol 47 no 2 pp 563ndash581 2015
[6] S Fallahzadeh H Bahrami and M Tayarani ldquoA novel dual-band bandstop waveguide filter using split ring resonatorsrdquoProgress in Electromagnetics Research Letters vol 12 pp 133ndash139 2009
[7] I Ohta Y Yumita K Toda and M Kishihara ldquoCruciformdirectional couplers in H-plane rectangular waveguiderdquo in Pro-ceedings of the Asia-Pacific Microwave Conference (APMC rsquo05)vol 2 December 2005
[8] A Patel Y Kosta N Chhasatia and F Raval ldquoDesign andfabrication of microwave waveguide resonator with improvedcharacteristic responserdquo European Journal of Scientific Researchvol 102 no 2 pp 163ndash174 2013
[9] R S Elliott and L A Kurtz ldquoThe design of small slot arraysrdquoIEEE Transactions on Antennas and Propagation vol 26 no 2pp 214ndash219 1978
[10] R S Elliott ldquoAn improved design procedure for small arrays ofshunt slotsrdquo IEEE Transactions on Antennas and Propagationvol 31 no 1 pp 48ndash53 1983
[11] A F Stevenson ldquoTheory of slots in rectangular wave-guidesrdquoJournal of Applied Physics vol 19 pp 24ndash38 1948
[12] W Coburn M Litz J Miletta N Tesny L Dilks and B KingldquoA slotted-waveguide array for high-power microwave trans-missionrdquo Progress Report for FY 2000 US Army ResearchLaboratory Adelphi Md USA 2001
[13] F Raval Y P Kosta J Makwana and A V Patel ldquoDesign amp im-plementation of reduced size microstrip patch antenna withmetamaterial defected ground planerdquo in Proceedings of the 2ndInternational Conference on Communication and Signal Proc-essing (ICCSP rsquo13) pp 186ndash190 IEEE Melmaruvathur IndiaApril 2013
[14] M Kahrizi T K Sarkar and Z AMaricevic ldquoAnalysis of a wideradiating slot in the ground plane of a microstrip linerdquo IEEETransactions onMicrowaveTheory and Techniques vol 41 no 1pp 29ndash37 1993
[15] J Galejst ldquoAdmittance of a rectangular slot which is backed bya rectangular cavityrdquo IEEE Transactions on Antennas and Prop-agation vol 11 no 2 pp 119ndash126 1963
[16] K-LWongCompact andBroadbandMicrostripAntennas JohnWiley amp Sons New York NY USA 2002
[17] W-S Chen ldquoSingle-feed dual-frequency rectangularmicrostripantenna with square slotrdquo Electronics Letters vol 34 no 3 pp231ndash232 1998
[18] D Busuioc M Shahabadi A Borji G Shaker and S Safavi-Naeini ldquoSubstrate integrated waveguide antenna feedmdashdesignmethodology and validationrdquo in Proceedings of the IEEE Anten-nas and Propagation Society International Symposium (AP-Srsquo07) pp 2666ndash2669 Honolulu Hawaii USA June 2007
[19] H Kumar R Jadhav and S Ranade ldquoA review on substrateintegrated waveguide and its microstrip interconnectrdquo Journalof Electronics and Communication Engineering vol 3 no 5 pp36ndash40 2012
[20] M Bozzi F XuDDeslandes andKWu ldquoModeling and designconsiderations for substrate integrated waveguide circuits andcomponentsrdquo in Proceedings of the 8th International Conferenceon Telecommunications in Modern Satellite Cable and Broad-casting Services (TELSIKS rsquo07) pp P-7ndashP-16 IEEE Nis SerbiaSeptember 2007
[21] S Moitra A Mukhopadhyay and A Bhattacharjee ldquoKu-bandsubstrate integrated waveguide (SIW) slot array antenna fornext generation networksrdquo Global Journal of Computer Scienceand Technology E Network Web amp Security vol 13 no 5 pp11ndash16 2013
[22] A J Farrall and P R Young ldquoIntegrated waveguide slot anten-nasrdquo Electronics Letters vol 40 no 16 pp 974ndash975 2004
[23] D PozarMicrowave Engineering JohnWiley amp Sons HobokenNJ USA 3rd edition 2005
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
8 International Journal of Microwave Science and Technology
Y
Z
53483e + 00033392e + 00013301e + 000minus67903e minus 001minus26881e + 000minus46972e + 000minus67063e + 000minus87154e + 000minus10725e + 001minus12734e + 001minus14743e + 001minus16752e + 001minus18761e + 001minus20770e + 001minus22779e + 001minus24788e + 001minus26797e + 001
GainTotal (dB)
(a)
080
160
240
320
90
60
300
150
120
Curve inforETotal
Setup1 LastAdaptiveFreq = 71GHz Theta = 90degldquo ldquordquo rdquo
minus30
minus60
minus90
minus120
minus150minus180
(b)
Figure 11 (a) Gain plot and (b) radiation pattern for I shape logarithmic slots array antenna
1424mm 3376mm
1702mm
0508mm
9mm 10mm30mm
15mm 21mm
Figure 12 3rd proposed structure contains trapezoidal logarithmic slots array antenna
m2
m3
m4m5 m6
m7
m8m1
Curve info
Setup1 sweep
700 800 900 1000 1100 1200 1300 1400 1500600Freq (GHz)
minus3500
minus3000
minus2500
minus2000
minus1500
minus1000
minus500
000
Name X Y
m1 67300m2 78400m3 103800m4 110700m5 114300m6 121400m7 128100m8 143600 minus183495
minus300236
minus181027minus163299
minus202328
minus270798
minus154970minus159939
S11 (dB)
S 11
(dB)
Figure 13 11987811plot for trapezoidal logarithmic slots array antenna
119 GHz) and two in Ku band (1395 and 145 GHz)The gainplot and radiation pattern for 67GHz frequency are shownin Figures 11(a) and 11(b) which shows that it generates gainof 5 dB which is half compared to first proposed structure
Third proposed structure contains trapezoidal logarith-mic slots array as shown in Figure 12 Distances of all the slots
m1 m2 m3 m4 m5 m6 m7 m8
700 800 900 1000 1100 1200 1300 1400 1500600Freq (GHz)
000500
100015002000250030003500
VSW
R(1)
Curve infoVSWR(1)
Setup1 sweep
Name X Ym1 67200 13759m2 78400 14037m3 103800 10926m4 110700 12157m5 114300 13601m6 121400 12842m7 128000 10823m8 143700 12861
Figure 14 VSWR of 3rd proposed trapezoidal logarithmic slotsarray antenna
are the same as 1st proposed design Simulated result of theproposed structure is shown in Figure 13 which shows higherreturn loss occurring at eight different frequencies two in Cband (67 and 754GHz) four in X band (1025 11 1143 and
International Journal of Microwave Science and Technology 9
10300e + 001
79774e + 000
33329e + 00056551e + 000
10107e + 000minus13115e + 000minus36337e + 000minus59560e + 000minus82782e + 000minus10600e + 001minus12923e + 001minus15245e + 001minus17567e + 001minus19889e + 001minus22211e + 001
minus26856e + 001
minus24534e + 001
GainTotal (dB)
Y
Z
(a)
Curve inforETotal
Setup1 LastAdaptiveFreq = 71GHz Theta = 90degldquo ldquordquo rdquo
minus30
minus90
minus120
minus150
minus180
minus60
200
400
600
800
90
60
300
150
120
(b)
Figure 15 (a) Gain plot and (b) radiation pattern for trapezoidal logarithmic slots array antenna
Figure 16 Fabricated model of logarithmic rectangular slots arrayantenna
5 10 15
minus30
minus25
minus20
minus15
minus10
minus5
0
Simulated S11 (dB)Measured S11 (dB)
Figure 17 11987811of logarithmic rectangular slots array antenna
1214GHz) and Ku band (1281 and 1436GHz) Its VSWR isshown in Figure 14Gain plot and radiation pattern are shownin Figures 15(a) and 15(b) respectively It gives more than10 dB gain at 67 GHz frequency
Simulated gainMeasured gain
00 30 60 90 120 150 180 210 240 270 300 360330
1
2
3
4
5
6
7
8
9
10
Figure 18 Gain of logarithmic rectangular slots array antenna
5 Measured Results
Logarithmic rectangular slots array antenna has been fabri-cated on Rogers RT Duroid 5880 high frequency substratewith a thickness of 0787mm relative permittivity of 22 andrelative permeability of 1 and loss tangent of 00009 The topside of the antenna has logarithmic slots and the other side isground planeThe photograph of fabricated antenna is shownin Figure 16
The antenna 11987811parameter and gain are measured using
the Vector Network Analyzer MVNA-8-350 with probe sta-tion The simulated and measured 119878
11parameter for antenna
is shown in Figure 17 A slight difference is observed between
10 International Journal of Microwave Science and Technology
Radiation efficiency
100
095
090
085
HFSSCurve info
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Radiation efficiency
Radiation efficiency
Setup1 LastAdaptiveFreq = 71GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Freq = 71GHz Theta = 10degldquo ldquordquo rdquo
Freq = 71GHz Theta = 20degldquo ldquordquo rdquo
Freq = 71GHz Theta = 50degldquo ldquordquo rdquo
Freq = 71GHz Theta = 40degldquo ldquordquo rdquo
Freq = 71GHz Theta = 60degldquo ldquordquo rdquo
Freq = 71GHz Theta = 30degldquo ldquordquo rdquo
(a)
Radiation efficiency
HFSS design2Curve info
096
092
088
084
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 10degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 20degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 50degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 40degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 60degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 30degldquo ldquordquo rdquo
(b)
Figure 19 Radiation efficiency of logarithmic rectangular slots array antenna in (a) C band and (b) X band
the measured value and simulated value The differencebetween the measured and simulated 119878
11of the antenna is
caused by the microstrip to SIW transitionThe simulated and measured gain of the antenna are
shown in Figure 18Themaximummeasured gain is also veryclose to 10 dB at 7GHz for the antenna which is max Themeasured result shows that the bandwidth of the antennacovers over 300MHz while the gain of the antenna is keptalmost constantwithin such awide bandwidth of the antennaSimulation results specify that metallic and dielectric lossesdo not have a substantial effect on the bandwidth andmatching condition of the antenna while they decrease themeasured gain of antenna by 05 dB The apparent differencebetween the simulation and measured gains might be dueto the calibration linked tolerance range of the antennareference in anechoic chamber
The radiation pattern of the antenna at resonant fre-quency is shown in Figure 18 The radiation pattern mea-surement is carried out in a conventional far field anechoicchamber which uses a V connector to connect the antennaDue to the size of the connector compared to the antenna therear radiation patterns were not incorporated in the resultsHowever the similar effects were observed in the simulationresults and most significantly the radiating behavior of theantenna is very similar to simulation results As shown inFigures 19(a) and 19(b) they represent the radiation efficiencyin C band and X band respectively which is 92 and 88
6 Observation and Discussion
From the simulation results we have observed the followingthings
(i) All the structure gives six or more than six resonantfrequencies in C band X band and Ku band
(ii) Gain generated by rectangular and trapezoidal log-arithmic slots array antenna is more than 10 dBcompared to I shape logarithmic slots array antenna
(iii) Isolation between two radiation bands ismuch higherin trapezoidal logarithmic slots array antenna andalso generates low leakage loss in stop band
(iv) Size of entire proposed antennas is compact com-pared to traditional antennas which are proposed forhigh gain applications
(v) Bandwidth produced by all the antennas at resonantfrequencies is more than 100MHz
7 Conclusion
From the design and simulation results it is clear that allthe antennas are compact in size and they are capable togenerate multiband frequencies which are very importantfactors for the proposed design process of antennas Antennasbased on SIW technology have been proposed in this paper
International Journal of Microwave Science and Technology 11
These structures can find many applications in C band and Xband for radar and remote sensingmechanism and are one ofthe major areas in docking satellite where communication isdone in C band while ranging is carried out in X band So thisantenna fulfilled both requirements instead of using two dif-ferent antennas Significant increment of gain parameter hasbeen obtained for introduction of more number and varietyof shapes of slots Compared to identical slots logarithmicslots give higher gain The effect has been extensively studiedunlike any other recent publication in this fieldThe structureis very simple and development of the prototype is easy inpresence of advanced PCB fabrication technology
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] P N Richardson and H Y Lee ldquoDesign and analysis of slottedwaveguide arraysrdquoMicrowave Journal vol 31 pp 109ndash125 1988
[2] S Ravish A Patel V V Dwivedi and H B Pandya ldquoDesigndevelopment and fabrication of post coupled band pass waveg-uide filter at 112 GHz for radiometerrdquo Microwave Journal vol51 2008
[3] A Patel Y Kosta N Chhasatia and K Pandya ldquoMultiple bandwaveguide based microwave resonatorrdquo in Proceedings of the1st International Conference on Advances in Engineering Scienceand Management (ICAESM rsquo12) pp 84ndash87 NagapattinamIndia March 2012
[4] S R Rengarajan ldquoCompound radiating slots in a broad wall ofa rectangular waveguiderdquo IEEE Transactions on Antennas andPropagation vol 37 no 9 pp 1116ndash1123 1989
[5] A Patel and Y P Kosta ldquoMultiple-band waveguide based band-stop filterrdquo International Journal of Applied Electromagnetics andMechanics vol 47 no 2 pp 563ndash581 2015
[6] S Fallahzadeh H Bahrami and M Tayarani ldquoA novel dual-band bandstop waveguide filter using split ring resonatorsrdquoProgress in Electromagnetics Research Letters vol 12 pp 133ndash139 2009
[7] I Ohta Y Yumita K Toda and M Kishihara ldquoCruciformdirectional couplers in H-plane rectangular waveguiderdquo in Pro-ceedings of the Asia-Pacific Microwave Conference (APMC rsquo05)vol 2 December 2005
[8] A Patel Y Kosta N Chhasatia and F Raval ldquoDesign andfabrication of microwave waveguide resonator with improvedcharacteristic responserdquo European Journal of Scientific Researchvol 102 no 2 pp 163ndash174 2013
[9] R S Elliott and L A Kurtz ldquoThe design of small slot arraysrdquoIEEE Transactions on Antennas and Propagation vol 26 no 2pp 214ndash219 1978
[10] R S Elliott ldquoAn improved design procedure for small arrays ofshunt slotsrdquo IEEE Transactions on Antennas and Propagationvol 31 no 1 pp 48ndash53 1983
[11] A F Stevenson ldquoTheory of slots in rectangular wave-guidesrdquoJournal of Applied Physics vol 19 pp 24ndash38 1948
[12] W Coburn M Litz J Miletta N Tesny L Dilks and B KingldquoA slotted-waveguide array for high-power microwave trans-missionrdquo Progress Report for FY 2000 US Army ResearchLaboratory Adelphi Md USA 2001
[13] F Raval Y P Kosta J Makwana and A V Patel ldquoDesign amp im-plementation of reduced size microstrip patch antenna withmetamaterial defected ground planerdquo in Proceedings of the 2ndInternational Conference on Communication and Signal Proc-essing (ICCSP rsquo13) pp 186ndash190 IEEE Melmaruvathur IndiaApril 2013
[14] M Kahrizi T K Sarkar and Z AMaricevic ldquoAnalysis of a wideradiating slot in the ground plane of a microstrip linerdquo IEEETransactions onMicrowaveTheory and Techniques vol 41 no 1pp 29ndash37 1993
[15] J Galejst ldquoAdmittance of a rectangular slot which is backed bya rectangular cavityrdquo IEEE Transactions on Antennas and Prop-agation vol 11 no 2 pp 119ndash126 1963
[16] K-LWongCompact andBroadbandMicrostripAntennas JohnWiley amp Sons New York NY USA 2002
[17] W-S Chen ldquoSingle-feed dual-frequency rectangularmicrostripantenna with square slotrdquo Electronics Letters vol 34 no 3 pp231ndash232 1998
[18] D Busuioc M Shahabadi A Borji G Shaker and S Safavi-Naeini ldquoSubstrate integrated waveguide antenna feedmdashdesignmethodology and validationrdquo in Proceedings of the IEEE Anten-nas and Propagation Society International Symposium (AP-Srsquo07) pp 2666ndash2669 Honolulu Hawaii USA June 2007
[19] H Kumar R Jadhav and S Ranade ldquoA review on substrateintegrated waveguide and its microstrip interconnectrdquo Journalof Electronics and Communication Engineering vol 3 no 5 pp36ndash40 2012
[20] M Bozzi F XuDDeslandes andKWu ldquoModeling and designconsiderations for substrate integrated waveguide circuits andcomponentsrdquo in Proceedings of the 8th International Conferenceon Telecommunications in Modern Satellite Cable and Broad-casting Services (TELSIKS rsquo07) pp P-7ndashP-16 IEEE Nis SerbiaSeptember 2007
[21] S Moitra A Mukhopadhyay and A Bhattacharjee ldquoKu-bandsubstrate integrated waveguide (SIW) slot array antenna fornext generation networksrdquo Global Journal of Computer Scienceand Technology E Network Web amp Security vol 13 no 5 pp11ndash16 2013
[22] A J Farrall and P R Young ldquoIntegrated waveguide slot anten-nasrdquo Electronics Letters vol 40 no 16 pp 974ndash975 2004
[23] D PozarMicrowave Engineering JohnWiley amp Sons HobokenNJ USA 3rd edition 2005
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
International Journal of Microwave Science and Technology 9
10300e + 001
79774e + 000
33329e + 00056551e + 000
10107e + 000minus13115e + 000minus36337e + 000minus59560e + 000minus82782e + 000minus10600e + 001minus12923e + 001minus15245e + 001minus17567e + 001minus19889e + 001minus22211e + 001
minus26856e + 001
minus24534e + 001
GainTotal (dB)
Y
Z
(a)
Curve inforETotal
Setup1 LastAdaptiveFreq = 71GHz Theta = 90degldquo ldquordquo rdquo
minus30
minus90
minus120
minus150
minus180
minus60
200
400
600
800
90
60
300
150
120
(b)
Figure 15 (a) Gain plot and (b) radiation pattern for trapezoidal logarithmic slots array antenna
Figure 16 Fabricated model of logarithmic rectangular slots arrayantenna
5 10 15
minus30
minus25
minus20
minus15
minus10
minus5
0
Simulated S11 (dB)Measured S11 (dB)
Figure 17 11987811of logarithmic rectangular slots array antenna
1214GHz) and Ku band (1281 and 1436GHz) Its VSWR isshown in Figure 14Gain plot and radiation pattern are shownin Figures 15(a) and 15(b) respectively It gives more than10 dB gain at 67 GHz frequency
Simulated gainMeasured gain
00 30 60 90 120 150 180 210 240 270 300 360330
1
2
3
4
5
6
7
8
9
10
Figure 18 Gain of logarithmic rectangular slots array antenna
5 Measured Results
Logarithmic rectangular slots array antenna has been fabri-cated on Rogers RT Duroid 5880 high frequency substratewith a thickness of 0787mm relative permittivity of 22 andrelative permeability of 1 and loss tangent of 00009 The topside of the antenna has logarithmic slots and the other side isground planeThe photograph of fabricated antenna is shownin Figure 16
The antenna 11987811parameter and gain are measured using
the Vector Network Analyzer MVNA-8-350 with probe sta-tion The simulated and measured 119878
11parameter for antenna
is shown in Figure 17 A slight difference is observed between
10 International Journal of Microwave Science and Technology
Radiation efficiency
100
095
090
085
HFSSCurve info
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Radiation efficiency
Radiation efficiency
Setup1 LastAdaptiveFreq = 71GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Freq = 71GHz Theta = 10degldquo ldquordquo rdquo
Freq = 71GHz Theta = 20degldquo ldquordquo rdquo
Freq = 71GHz Theta = 50degldquo ldquordquo rdquo
Freq = 71GHz Theta = 40degldquo ldquordquo rdquo
Freq = 71GHz Theta = 60degldquo ldquordquo rdquo
Freq = 71GHz Theta = 30degldquo ldquordquo rdquo
(a)
Radiation efficiency
HFSS design2Curve info
096
092
088
084
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 10degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 20degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 50degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 40degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 60degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 30degldquo ldquordquo rdquo
(b)
Figure 19 Radiation efficiency of logarithmic rectangular slots array antenna in (a) C band and (b) X band
the measured value and simulated value The differencebetween the measured and simulated 119878
11of the antenna is
caused by the microstrip to SIW transitionThe simulated and measured gain of the antenna are
shown in Figure 18Themaximummeasured gain is also veryclose to 10 dB at 7GHz for the antenna which is max Themeasured result shows that the bandwidth of the antennacovers over 300MHz while the gain of the antenna is keptalmost constantwithin such awide bandwidth of the antennaSimulation results specify that metallic and dielectric lossesdo not have a substantial effect on the bandwidth andmatching condition of the antenna while they decrease themeasured gain of antenna by 05 dB The apparent differencebetween the simulation and measured gains might be dueto the calibration linked tolerance range of the antennareference in anechoic chamber
The radiation pattern of the antenna at resonant fre-quency is shown in Figure 18 The radiation pattern mea-surement is carried out in a conventional far field anechoicchamber which uses a V connector to connect the antennaDue to the size of the connector compared to the antenna therear radiation patterns were not incorporated in the resultsHowever the similar effects were observed in the simulationresults and most significantly the radiating behavior of theantenna is very similar to simulation results As shown inFigures 19(a) and 19(b) they represent the radiation efficiencyin C band and X band respectively which is 92 and 88
6 Observation and Discussion
From the simulation results we have observed the followingthings
(i) All the structure gives six or more than six resonantfrequencies in C band X band and Ku band
(ii) Gain generated by rectangular and trapezoidal log-arithmic slots array antenna is more than 10 dBcompared to I shape logarithmic slots array antenna
(iii) Isolation between two radiation bands ismuch higherin trapezoidal logarithmic slots array antenna andalso generates low leakage loss in stop band
(iv) Size of entire proposed antennas is compact com-pared to traditional antennas which are proposed forhigh gain applications
(v) Bandwidth produced by all the antennas at resonantfrequencies is more than 100MHz
7 Conclusion
From the design and simulation results it is clear that allthe antennas are compact in size and they are capable togenerate multiband frequencies which are very importantfactors for the proposed design process of antennas Antennasbased on SIW technology have been proposed in this paper
International Journal of Microwave Science and Technology 11
These structures can find many applications in C band and Xband for radar and remote sensingmechanism and are one ofthe major areas in docking satellite where communication isdone in C band while ranging is carried out in X band So thisantenna fulfilled both requirements instead of using two dif-ferent antennas Significant increment of gain parameter hasbeen obtained for introduction of more number and varietyof shapes of slots Compared to identical slots logarithmicslots give higher gain The effect has been extensively studiedunlike any other recent publication in this fieldThe structureis very simple and development of the prototype is easy inpresence of advanced PCB fabrication technology
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] P N Richardson and H Y Lee ldquoDesign and analysis of slottedwaveguide arraysrdquoMicrowave Journal vol 31 pp 109ndash125 1988
[2] S Ravish A Patel V V Dwivedi and H B Pandya ldquoDesigndevelopment and fabrication of post coupled band pass waveg-uide filter at 112 GHz for radiometerrdquo Microwave Journal vol51 2008
[3] A Patel Y Kosta N Chhasatia and K Pandya ldquoMultiple bandwaveguide based microwave resonatorrdquo in Proceedings of the1st International Conference on Advances in Engineering Scienceand Management (ICAESM rsquo12) pp 84ndash87 NagapattinamIndia March 2012
[4] S R Rengarajan ldquoCompound radiating slots in a broad wall ofa rectangular waveguiderdquo IEEE Transactions on Antennas andPropagation vol 37 no 9 pp 1116ndash1123 1989
[5] A Patel and Y P Kosta ldquoMultiple-band waveguide based band-stop filterrdquo International Journal of Applied Electromagnetics andMechanics vol 47 no 2 pp 563ndash581 2015
[6] S Fallahzadeh H Bahrami and M Tayarani ldquoA novel dual-band bandstop waveguide filter using split ring resonatorsrdquoProgress in Electromagnetics Research Letters vol 12 pp 133ndash139 2009
[7] I Ohta Y Yumita K Toda and M Kishihara ldquoCruciformdirectional couplers in H-plane rectangular waveguiderdquo in Pro-ceedings of the Asia-Pacific Microwave Conference (APMC rsquo05)vol 2 December 2005
[8] A Patel Y Kosta N Chhasatia and F Raval ldquoDesign andfabrication of microwave waveguide resonator with improvedcharacteristic responserdquo European Journal of Scientific Researchvol 102 no 2 pp 163ndash174 2013
[9] R S Elliott and L A Kurtz ldquoThe design of small slot arraysrdquoIEEE Transactions on Antennas and Propagation vol 26 no 2pp 214ndash219 1978
[10] R S Elliott ldquoAn improved design procedure for small arrays ofshunt slotsrdquo IEEE Transactions on Antennas and Propagationvol 31 no 1 pp 48ndash53 1983
[11] A F Stevenson ldquoTheory of slots in rectangular wave-guidesrdquoJournal of Applied Physics vol 19 pp 24ndash38 1948
[12] W Coburn M Litz J Miletta N Tesny L Dilks and B KingldquoA slotted-waveguide array for high-power microwave trans-missionrdquo Progress Report for FY 2000 US Army ResearchLaboratory Adelphi Md USA 2001
[13] F Raval Y P Kosta J Makwana and A V Patel ldquoDesign amp im-plementation of reduced size microstrip patch antenna withmetamaterial defected ground planerdquo in Proceedings of the 2ndInternational Conference on Communication and Signal Proc-essing (ICCSP rsquo13) pp 186ndash190 IEEE Melmaruvathur IndiaApril 2013
[14] M Kahrizi T K Sarkar and Z AMaricevic ldquoAnalysis of a wideradiating slot in the ground plane of a microstrip linerdquo IEEETransactions onMicrowaveTheory and Techniques vol 41 no 1pp 29ndash37 1993
[15] J Galejst ldquoAdmittance of a rectangular slot which is backed bya rectangular cavityrdquo IEEE Transactions on Antennas and Prop-agation vol 11 no 2 pp 119ndash126 1963
[16] K-LWongCompact andBroadbandMicrostripAntennas JohnWiley amp Sons New York NY USA 2002
[17] W-S Chen ldquoSingle-feed dual-frequency rectangularmicrostripantenna with square slotrdquo Electronics Letters vol 34 no 3 pp231ndash232 1998
[18] D Busuioc M Shahabadi A Borji G Shaker and S Safavi-Naeini ldquoSubstrate integrated waveguide antenna feedmdashdesignmethodology and validationrdquo in Proceedings of the IEEE Anten-nas and Propagation Society International Symposium (AP-Srsquo07) pp 2666ndash2669 Honolulu Hawaii USA June 2007
[19] H Kumar R Jadhav and S Ranade ldquoA review on substrateintegrated waveguide and its microstrip interconnectrdquo Journalof Electronics and Communication Engineering vol 3 no 5 pp36ndash40 2012
[20] M Bozzi F XuDDeslandes andKWu ldquoModeling and designconsiderations for substrate integrated waveguide circuits andcomponentsrdquo in Proceedings of the 8th International Conferenceon Telecommunications in Modern Satellite Cable and Broad-casting Services (TELSIKS rsquo07) pp P-7ndashP-16 IEEE Nis SerbiaSeptember 2007
[21] S Moitra A Mukhopadhyay and A Bhattacharjee ldquoKu-bandsubstrate integrated waveguide (SIW) slot array antenna fornext generation networksrdquo Global Journal of Computer Scienceand Technology E Network Web amp Security vol 13 no 5 pp11ndash16 2013
[22] A J Farrall and P R Young ldquoIntegrated waveguide slot anten-nasrdquo Electronics Letters vol 40 no 16 pp 974ndash975 2004
[23] D PozarMicrowave Engineering JohnWiley amp Sons HobokenNJ USA 3rd edition 2005
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
10 International Journal of Microwave Science and Technology
Radiation efficiency
100
095
090
085
HFSSCurve info
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Radiation efficiency
Radiation efficiency
Setup1 LastAdaptiveFreq = 71GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Radiation efficiencySetup1 LastAdaptive
Freq = 71GHz Theta = 10degldquo ldquordquo rdquo
Freq = 71GHz Theta = 20degldquo ldquordquo rdquo
Freq = 71GHz Theta = 50degldquo ldquordquo rdquo
Freq = 71GHz Theta = 40degldquo ldquordquo rdquo
Freq = 71GHz Theta = 60degldquo ldquordquo rdquo
Freq = 71GHz Theta = 30degldquo ldquordquo rdquo
(a)
Radiation efficiency
HFSS design2Curve info
096
092
088
084
90
60
300
150
120
minus30
minus60
minus90
minus120
minus150minus180
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Setup2 LastAdaptive
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 0degldquo ldquordquo rdquo
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Radiation efficiency
Freq = 1038GHz Theta = 10degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 20degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 50degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 40degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 60degldquo ldquordquo rdquo
Freq = 1038GHz Theta = 30degldquo ldquordquo rdquo
(b)
Figure 19 Radiation efficiency of logarithmic rectangular slots array antenna in (a) C band and (b) X band
the measured value and simulated value The differencebetween the measured and simulated 119878
11of the antenna is
caused by the microstrip to SIW transitionThe simulated and measured gain of the antenna are
shown in Figure 18Themaximummeasured gain is also veryclose to 10 dB at 7GHz for the antenna which is max Themeasured result shows that the bandwidth of the antennacovers over 300MHz while the gain of the antenna is keptalmost constantwithin such awide bandwidth of the antennaSimulation results specify that metallic and dielectric lossesdo not have a substantial effect on the bandwidth andmatching condition of the antenna while they decrease themeasured gain of antenna by 05 dB The apparent differencebetween the simulation and measured gains might be dueto the calibration linked tolerance range of the antennareference in anechoic chamber
The radiation pattern of the antenna at resonant fre-quency is shown in Figure 18 The radiation pattern mea-surement is carried out in a conventional far field anechoicchamber which uses a V connector to connect the antennaDue to the size of the connector compared to the antenna therear radiation patterns were not incorporated in the resultsHowever the similar effects were observed in the simulationresults and most significantly the radiating behavior of theantenna is very similar to simulation results As shown inFigures 19(a) and 19(b) they represent the radiation efficiencyin C band and X band respectively which is 92 and 88
6 Observation and Discussion
From the simulation results we have observed the followingthings
(i) All the structure gives six or more than six resonantfrequencies in C band X band and Ku band
(ii) Gain generated by rectangular and trapezoidal log-arithmic slots array antenna is more than 10 dBcompared to I shape logarithmic slots array antenna
(iii) Isolation between two radiation bands ismuch higherin trapezoidal logarithmic slots array antenna andalso generates low leakage loss in stop band
(iv) Size of entire proposed antennas is compact com-pared to traditional antennas which are proposed forhigh gain applications
(v) Bandwidth produced by all the antennas at resonantfrequencies is more than 100MHz
7 Conclusion
From the design and simulation results it is clear that allthe antennas are compact in size and they are capable togenerate multiband frequencies which are very importantfactors for the proposed design process of antennas Antennasbased on SIW technology have been proposed in this paper
International Journal of Microwave Science and Technology 11
These structures can find many applications in C band and Xband for radar and remote sensingmechanism and are one ofthe major areas in docking satellite where communication isdone in C band while ranging is carried out in X band So thisantenna fulfilled both requirements instead of using two dif-ferent antennas Significant increment of gain parameter hasbeen obtained for introduction of more number and varietyof shapes of slots Compared to identical slots logarithmicslots give higher gain The effect has been extensively studiedunlike any other recent publication in this fieldThe structureis very simple and development of the prototype is easy inpresence of advanced PCB fabrication technology
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] P N Richardson and H Y Lee ldquoDesign and analysis of slottedwaveguide arraysrdquoMicrowave Journal vol 31 pp 109ndash125 1988
[2] S Ravish A Patel V V Dwivedi and H B Pandya ldquoDesigndevelopment and fabrication of post coupled band pass waveg-uide filter at 112 GHz for radiometerrdquo Microwave Journal vol51 2008
[3] A Patel Y Kosta N Chhasatia and K Pandya ldquoMultiple bandwaveguide based microwave resonatorrdquo in Proceedings of the1st International Conference on Advances in Engineering Scienceand Management (ICAESM rsquo12) pp 84ndash87 NagapattinamIndia March 2012
[4] S R Rengarajan ldquoCompound radiating slots in a broad wall ofa rectangular waveguiderdquo IEEE Transactions on Antennas andPropagation vol 37 no 9 pp 1116ndash1123 1989
[5] A Patel and Y P Kosta ldquoMultiple-band waveguide based band-stop filterrdquo International Journal of Applied Electromagnetics andMechanics vol 47 no 2 pp 563ndash581 2015
[6] S Fallahzadeh H Bahrami and M Tayarani ldquoA novel dual-band bandstop waveguide filter using split ring resonatorsrdquoProgress in Electromagnetics Research Letters vol 12 pp 133ndash139 2009
[7] I Ohta Y Yumita K Toda and M Kishihara ldquoCruciformdirectional couplers in H-plane rectangular waveguiderdquo in Pro-ceedings of the Asia-Pacific Microwave Conference (APMC rsquo05)vol 2 December 2005
[8] A Patel Y Kosta N Chhasatia and F Raval ldquoDesign andfabrication of microwave waveguide resonator with improvedcharacteristic responserdquo European Journal of Scientific Researchvol 102 no 2 pp 163ndash174 2013
[9] R S Elliott and L A Kurtz ldquoThe design of small slot arraysrdquoIEEE Transactions on Antennas and Propagation vol 26 no 2pp 214ndash219 1978
[10] R S Elliott ldquoAn improved design procedure for small arrays ofshunt slotsrdquo IEEE Transactions on Antennas and Propagationvol 31 no 1 pp 48ndash53 1983
[11] A F Stevenson ldquoTheory of slots in rectangular wave-guidesrdquoJournal of Applied Physics vol 19 pp 24ndash38 1948
[12] W Coburn M Litz J Miletta N Tesny L Dilks and B KingldquoA slotted-waveguide array for high-power microwave trans-missionrdquo Progress Report for FY 2000 US Army ResearchLaboratory Adelphi Md USA 2001
[13] F Raval Y P Kosta J Makwana and A V Patel ldquoDesign amp im-plementation of reduced size microstrip patch antenna withmetamaterial defected ground planerdquo in Proceedings of the 2ndInternational Conference on Communication and Signal Proc-essing (ICCSP rsquo13) pp 186ndash190 IEEE Melmaruvathur IndiaApril 2013
[14] M Kahrizi T K Sarkar and Z AMaricevic ldquoAnalysis of a wideradiating slot in the ground plane of a microstrip linerdquo IEEETransactions onMicrowaveTheory and Techniques vol 41 no 1pp 29ndash37 1993
[15] J Galejst ldquoAdmittance of a rectangular slot which is backed bya rectangular cavityrdquo IEEE Transactions on Antennas and Prop-agation vol 11 no 2 pp 119ndash126 1963
[16] K-LWongCompact andBroadbandMicrostripAntennas JohnWiley amp Sons New York NY USA 2002
[17] W-S Chen ldquoSingle-feed dual-frequency rectangularmicrostripantenna with square slotrdquo Electronics Letters vol 34 no 3 pp231ndash232 1998
[18] D Busuioc M Shahabadi A Borji G Shaker and S Safavi-Naeini ldquoSubstrate integrated waveguide antenna feedmdashdesignmethodology and validationrdquo in Proceedings of the IEEE Anten-nas and Propagation Society International Symposium (AP-Srsquo07) pp 2666ndash2669 Honolulu Hawaii USA June 2007
[19] H Kumar R Jadhav and S Ranade ldquoA review on substrateintegrated waveguide and its microstrip interconnectrdquo Journalof Electronics and Communication Engineering vol 3 no 5 pp36ndash40 2012
[20] M Bozzi F XuDDeslandes andKWu ldquoModeling and designconsiderations for substrate integrated waveguide circuits andcomponentsrdquo in Proceedings of the 8th International Conferenceon Telecommunications in Modern Satellite Cable and Broad-casting Services (TELSIKS rsquo07) pp P-7ndashP-16 IEEE Nis SerbiaSeptember 2007
[21] S Moitra A Mukhopadhyay and A Bhattacharjee ldquoKu-bandsubstrate integrated waveguide (SIW) slot array antenna fornext generation networksrdquo Global Journal of Computer Scienceand Technology E Network Web amp Security vol 13 no 5 pp11ndash16 2013
[22] A J Farrall and P R Young ldquoIntegrated waveguide slot anten-nasrdquo Electronics Letters vol 40 no 16 pp 974ndash975 2004
[23] D PozarMicrowave Engineering JohnWiley amp Sons HobokenNJ USA 3rd edition 2005
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
International Journal of Microwave Science and Technology 11
These structures can find many applications in C band and Xband for radar and remote sensingmechanism and are one ofthe major areas in docking satellite where communication isdone in C band while ranging is carried out in X band So thisantenna fulfilled both requirements instead of using two dif-ferent antennas Significant increment of gain parameter hasbeen obtained for introduction of more number and varietyof shapes of slots Compared to identical slots logarithmicslots give higher gain The effect has been extensively studiedunlike any other recent publication in this fieldThe structureis very simple and development of the prototype is easy inpresence of advanced PCB fabrication technology
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
References
[1] P N Richardson and H Y Lee ldquoDesign and analysis of slottedwaveguide arraysrdquoMicrowave Journal vol 31 pp 109ndash125 1988
[2] S Ravish A Patel V V Dwivedi and H B Pandya ldquoDesigndevelopment and fabrication of post coupled band pass waveg-uide filter at 112 GHz for radiometerrdquo Microwave Journal vol51 2008
[3] A Patel Y Kosta N Chhasatia and K Pandya ldquoMultiple bandwaveguide based microwave resonatorrdquo in Proceedings of the1st International Conference on Advances in Engineering Scienceand Management (ICAESM rsquo12) pp 84ndash87 NagapattinamIndia March 2012
[4] S R Rengarajan ldquoCompound radiating slots in a broad wall ofa rectangular waveguiderdquo IEEE Transactions on Antennas andPropagation vol 37 no 9 pp 1116ndash1123 1989
[5] A Patel and Y P Kosta ldquoMultiple-band waveguide based band-stop filterrdquo International Journal of Applied Electromagnetics andMechanics vol 47 no 2 pp 563ndash581 2015
[6] S Fallahzadeh H Bahrami and M Tayarani ldquoA novel dual-band bandstop waveguide filter using split ring resonatorsrdquoProgress in Electromagnetics Research Letters vol 12 pp 133ndash139 2009
[7] I Ohta Y Yumita K Toda and M Kishihara ldquoCruciformdirectional couplers in H-plane rectangular waveguiderdquo in Pro-ceedings of the Asia-Pacific Microwave Conference (APMC rsquo05)vol 2 December 2005
[8] A Patel Y Kosta N Chhasatia and F Raval ldquoDesign andfabrication of microwave waveguide resonator with improvedcharacteristic responserdquo European Journal of Scientific Researchvol 102 no 2 pp 163ndash174 2013
[9] R S Elliott and L A Kurtz ldquoThe design of small slot arraysrdquoIEEE Transactions on Antennas and Propagation vol 26 no 2pp 214ndash219 1978
[10] R S Elliott ldquoAn improved design procedure for small arrays ofshunt slotsrdquo IEEE Transactions on Antennas and Propagationvol 31 no 1 pp 48ndash53 1983
[11] A F Stevenson ldquoTheory of slots in rectangular wave-guidesrdquoJournal of Applied Physics vol 19 pp 24ndash38 1948
[12] W Coburn M Litz J Miletta N Tesny L Dilks and B KingldquoA slotted-waveguide array for high-power microwave trans-missionrdquo Progress Report for FY 2000 US Army ResearchLaboratory Adelphi Md USA 2001
[13] F Raval Y P Kosta J Makwana and A V Patel ldquoDesign amp im-plementation of reduced size microstrip patch antenna withmetamaterial defected ground planerdquo in Proceedings of the 2ndInternational Conference on Communication and Signal Proc-essing (ICCSP rsquo13) pp 186ndash190 IEEE Melmaruvathur IndiaApril 2013
[14] M Kahrizi T K Sarkar and Z AMaricevic ldquoAnalysis of a wideradiating slot in the ground plane of a microstrip linerdquo IEEETransactions onMicrowaveTheory and Techniques vol 41 no 1pp 29ndash37 1993
[15] J Galejst ldquoAdmittance of a rectangular slot which is backed bya rectangular cavityrdquo IEEE Transactions on Antennas and Prop-agation vol 11 no 2 pp 119ndash126 1963
[16] K-LWongCompact andBroadbandMicrostripAntennas JohnWiley amp Sons New York NY USA 2002
[17] W-S Chen ldquoSingle-feed dual-frequency rectangularmicrostripantenna with square slotrdquo Electronics Letters vol 34 no 3 pp231ndash232 1998
[18] D Busuioc M Shahabadi A Borji G Shaker and S Safavi-Naeini ldquoSubstrate integrated waveguide antenna feedmdashdesignmethodology and validationrdquo in Proceedings of the IEEE Anten-nas and Propagation Society International Symposium (AP-Srsquo07) pp 2666ndash2669 Honolulu Hawaii USA June 2007
[19] H Kumar R Jadhav and S Ranade ldquoA review on substrateintegrated waveguide and its microstrip interconnectrdquo Journalof Electronics and Communication Engineering vol 3 no 5 pp36ndash40 2012
[20] M Bozzi F XuDDeslandes andKWu ldquoModeling and designconsiderations for substrate integrated waveguide circuits andcomponentsrdquo in Proceedings of the 8th International Conferenceon Telecommunications in Modern Satellite Cable and Broad-casting Services (TELSIKS rsquo07) pp P-7ndashP-16 IEEE Nis SerbiaSeptember 2007
[21] S Moitra A Mukhopadhyay and A Bhattacharjee ldquoKu-bandsubstrate integrated waveguide (SIW) slot array antenna fornext generation networksrdquo Global Journal of Computer Scienceand Technology E Network Web amp Security vol 13 no 5 pp11ndash16 2013
[22] A J Farrall and P R Young ldquoIntegrated waveguide slot anten-nasrdquo Electronics Letters vol 40 no 16 pp 974ndash975 2004
[23] D PozarMicrowave Engineering JohnWiley amp Sons HobokenNJ USA 3rd edition 2005
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of