design and improvement in bandwidth using single … · the ground plane. for a good antenna p erfo...

DESIGN AND IMPROVEMENT IN BANDWIDTH USING SINGLE WIDE

BAND RECTANGULAR MICROSTRIP PATCHES ANTENNA

Dr.M.AntoBennet

1 , K.Vijyalakshmi

2, Pushpa

3

Professor1, 2,3

UG students ,Department of Electronics and Communication Engineering Vel tech, Chennai-600062

Email: [email protected],

ABSTRACT:

A single layer microstrip fed patch antenna with capabilities of bandwidth enhancement

is proposed. We introduced slots at ground structure to improve the overall bandwidth and width

of the slot which directly controls the bandwidth and the optimized parameters have set as

0.2mm. Selection of substrate is the most important task in microstrip patch antenna design. RT

duroid is the substrate used here. The working principle, design procedures are extensively

described. Finally, a prototype antenna operating at 4.65 GHz to 5.10 GHz is designed and

fabricated. The measured result shows that the bandwidth is increased up to 150MHz than that of

the traditional patch antenna.

Keywords:

INTRODUCTION

An antenna is designed to transmit or receive radio waves.MPA is a type of an antenna that

consists of a radiating patch on one side of a dielectric substrate and a ground plane on the other

side. The bottom surface of a thin dielectric substrate is completely covered with metallization

that serves as a ground plane. The metallization is usually copper or gold that has been

electrodeposited or rolled on. With the former, the copper is chemically deposited on the

surface, while a thin copper sheet is attached by an adhesive for the latter. The electromagnetic

waves fringe off the top patch into the substrate, reflecting off the round plane and radiates out

into the air. MPAs radiate primarily because of the fringing fields between the patch edge and

the ground plane.For a good antenna performance, a thick dielectric substrate having a low

dielectric constant is desirable as it provides better efficiency, larger bandwidth and better

radiation. However, such a configuration leads to a larger antenna size. To design as smaller

sized MPA, higher dielectric constants must be used but in turn, it results on narrower

bandwidth and less efficiency, thus a compromise must be reached between antenna dimensions

and performance. The rectangular shaped patch antenna is the most common type of MPAs

because of its ease in the analysis, fabrication, and its attractive radiation characteristics

especially low cross polarization radiation

LITERATURE SURVEY:

Microstrip patch antenna is more preferred among antenna structures in recent years due

to their low profile and ease of fabrication. It can be used in many application especially in

wireless communication and in satellite communication. The selection of proper substrate is one

of the major task in microstrip patch antenna design. A new design approach for a Microstrip

Patch Antenna to achieve a wide bandwidth with multislot. The author [1] had proposed a design

International Journal of Pure and Applied MathematicsVolume 119 No. 15 2018, 337-350ISSN: 1314-3395 (on-line version)url: http://www.acadpubl.eu/hub/Special Issue http://www.acadpubl.eu/hub/

337

with a rectangular shorted patch in order to achieve a wideband performance and also reduction

in size. The author [2] had proposed a compact filtering antenna with high band-edge gain

selectivity using a composite right-/left-handed (CRLH) resonator and a defected ground

structure, which achieves a twice wider bandwidth. The author [3] had proposed a L- shaped

probe which is suitable feed technique for the thick microstrip antenna this new feeding

technique is quite similar to that of the U-shaped slot patch antenna ,which means that both

exhibit broad- band and high-gain characteristics. the author [4] had proposed a patch antenna of

a thick substrate with the new capacitive feed probe to achieve the performance that is typically

required for modern wireless communication systems, while also reducing the manufacturing

costs. The author [5] had proposed U-Slot Microstrip Patch Antenna Array in single layer. The

above design helps to form array easily and increase the bandwidth from18% ranging from 5.65

GHz to 6.78 GHz. The author [6] had proposed a capacitive probe compensation technique with

the thick substrate to enhance the bandwidth capabilities of these CP patch antennas. The author

[7] had proposed a broad-band -slot rectangular patch antenna with the coaxial probe technique

.The achieved impedance bandwidth of the -slot patch antennas on microwave substrates are

27% .The author [8] had investigate a parameters that control the impedance and radiation

performance of proximity coupled stacked microstrip patch radiators which leads to 20% excess

of bandwith .The author[9] had proposed a single microstrip patch antenna having two-

dimensional photonic band gap (PBG) in the ground has been demonstrated experimentally

which helps for suppression of the resonance at the harmonic frequencies. The author[10] had

proposed a Design of Micro strip Patch Antennas Using Photonic Band gap Structure to the

feed line of microstrip antennas, which yield band stop characteristics, suppress higher order

harmonics.

PROPOSED SYSTEM:

This work presents a new compact coupled-fed patch antenna in a single-layer substrate.

By using a pair of λ/4 resonators, the bandwidth of the patch antenna is significantly enlarged

while other advantages of the patch antenna, such as low cost, low profile, and easy integration,

still remain. In the analysis, an equivalent circuit model is proposed to analyze and design this

proposed antenna. Our investigation shows that the bandwidth of this patch can be widened by

adjusting the gap between the patch and the λ /4 resonators. Its good performance is

demonstrated by comparison with a traditional insert-fed patch antenna. The measured and

simulated results show that the bandwidth has been enlarged by 150 MHZ. The slot is introduced

in the ground structure which increases the bandwidth considerably by 600MHz.The dielectric

RT duroid is used

RT DUROID 5870:

RT/duroid 5870 laminates are easily cut, sheared and machined to shape. They are

resistant to all solvents and reagents, hot or cold, normally used in etching printed circuits or in

plating edges and holes. Normally supplied as a laminate with electrodeposited m) or reverse

treated copper of ½ to 2 ounces/ ft.2 (8 to 70 EDC on both sides, RT/duroid 5870 composites can

also be clad with rolled copper foil for more critical electrical applications. Cladding with

aluminium, copper or brass plate may also be specified. When ordering RT/duroid 5870

International Journal of Pure and Applied Mathematics Special Issue

338

laminates, it is important to specify dielectric thickness, tolerance, rolled, electrodeposited or

reverse treated copper foil, and weight of copper foil required.

Bandwidth enhancement:

In this work, a single layer microstrip fed patch antenna with capabilities of both the

bandwidth enhancement and harmonic suppressions is proposed. In order to enhance the

bandwidth we introduced slots at ground structure to improve the overall bandwidth and width of

the slot which directly controls the bandwidth. Adding slots over the patch will increase the

overall bandwidth and better impedance matching. The presences of multi-slots restrict the patch

currents, at its resonance frequencies that provide lower return loss. This paper presents only the

simulated results and the proposed multi slot antenna which is tested in anechoic chamber and

the measured results shows that the bandwidth is increased up to 2.7 times than the traditional

patch antenna. Selection of substrate is the most important task in microstrip patch antenna

design. RT duroid is the substrate used here. RT/duroid 5870 laminates are easily cut, sheared

and machined to shape. They are resistant to all solvents and reagents, hot or cold, normally used

in etching printed circuits or in plating edges and holes. RT/duroid 5870 composites can also be

clad with rolled copper foil for more critical electrical applications. Cladding with aluminium,

copper or brass plate may also be specified. When ordering RT/duroid 5870 laminates, it is

important to specify dielectric thickness, tolerance, rolled, electrodeposited or reverse treated

copper foil, and weight of copper foil required.

Harmonic suppressions:

In addition to the bandwidth enhancement described above, the undesired harmonic

radiation at higher frequency can be effectively suppressed in the proposed technique. The

effectiveness of the harmonic suppressions is greatly influenced by the width of the gap and

operating bandwidth. To show the harmonic suppression, the |S11| of these two patches are

plotted together. There are many higher-order radiating modes beyond the dominant mode, but

somehow it will disappear in the proposed microstrip patch antenna design leading to the better

suppressions of harmonic radiations. Both the harmonic suppressions and the bandwidth

enhancement operate at 4.9 Ghz and are fabricated on RT duroid substrates with an relative

permittivity ofr = 2.33 and a thickness of h= 1.57 mm. To shows this evidently, it is compared

with the traditional microstrip patch antenna.

EXPERIMENTAL RESULTS

Basic Geometry –Traditional antenna

The basic geometry of the traditional patch is given in figure 1. The length𝐿 and width 𝑊

of the patch are given by

𝐿=19.1𝑚𝑚, 𝑊=27 𝑚𝑚


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Fig 1 Traditional Antenna

The substrate chosen has a dielectric constant Є𝑟 given by Єr=2.33,with a loss tangent

𝑡𝑎𝑛𝛿=0.002 .The height h of the substrate is chose to beh=1.57𝑚𝑚.The width of each microstrip

line section is chosen to be 4.5𝑚𝑚.

TABLE SPECIFICATION

Substrate RT Duroid

5870

Epsilon 2.33

Tangent loss 0.002

Total Length (L1) 46mm

Total Width (W1) 45mm

Width of the patch

(W)

27mm

Length of the patch

(L)

19.1mm

L1 6.3mm

Gap (G) 0.6mm

Width of the

Conductor (W2)

4.5mm

Simulation Results The microstrip patch antenna was designed using CST MICROWAVE STUDIO. The

performance of the antenna has been studied by comparing the Return loss, VSWR, Gain,

azimuthal and elevation patterns.


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RETURN LOSS

Fig 2.Return loss

The frequency range from 2 to 12 GHz is shown in the figure 2. The above plot shows

the simulated return loss on loss Y axis and frequency on X axis, the higher band is covered with

a return loss of -17dB at 4.9 GHz and unwanted harmonics radiation at high frequency such as

7.1 GHz, 8.9 GHz, and 11.9 GHz.

VSWR

Fig 3 Voltage Standing wave ratio

The above plot (fig3)shows that the simulated VSWR Result, with VSWR on Y axis and

frequency on X-axis, at 4.9GHz is 1.12


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Radiation Pattern

Fig 4 Radiation pattern at 4.9Ghz

Fig 5Polar Plot at 4.9 GHz

The above Polar plot (fig4,5)shows that simulated at 4.9 GHz

Geometry of Modified traditional antenna

The basic geometry of the traditional patch is given in figure 6. The length 𝐿 and width

𝑊 of the patch are given by𝐿=18 𝑚𝑚, 𝑊=27 𝑚𝑚

Fig 6 Modified traditional Antenna in CST Microwave studio

The substrate chosen has a dielectric constant Є𝑟 given by Єr=2.33,with a loss

tangent𝑡𝑎𝑛𝛿=0.002The height h of the substrate is chose to be h=1.57𝑚𝑚.


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SPECIFICATION

Substrate RT Duroid

5870

Epsilon 2.33

Tangent loss 0.002



Width of the patch (W) 27mm

Length of the patch (L) 18mm

L2 8.6mm

Gap (G) 1.75mm

Width of the

Conductor (W1)

4.5mm

Radius of the

conductor

0.5mm

Width of the

resonator(W2)

0.5mm

Return Loss

Fig 7 Return loss of Modified traditional antenna


the simulated return loss on loss Y axis and frequency on X axis, the bandwidth is starts from

4.65 GHz to 5.10 GHz band and unwanted harmonics radiation is supressed in modified

traditional antenna (Refer fig 2)


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VSWR

Fig 8 Return loss of Modified traditional antenna

The above plot(fig8) shows that the simulated VSWR Result, with VSWR on Y axis and

frequency on X-axis, at 4.65 GHz is 1.58 and 5.10 GHz is 1.98

Radiation Pattern

Fig.9 Radiation pattern

of Modified traditional

antenna

The above plot (fig 9)shows that 3D radiation pattern of the Modified traditional antenna at 4.9

GHz, itprovides gain of 7.30 dB


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Fig 10 Polar Plot at 4.9 GHz

The above Polar plot(fig10) shows that simulated at 4.9 GHz for modified traditional

antenna

Proposed Antenna:

Geometry structure

Fig 11Proposed Antenna (a).Front view (b) Back view

The substrate chosen has a dielectric constant Є𝑟 given by Єr=2.33, with a loss tangent

𝑡𝑎𝑛𝛿=0.0012 The height h of the substrate is chose to be h=2.1𝑚𝑚.Proposed slots at ground

structure to improve the overall bandwidth of the antenna. Optimized parameters as shown in

table 1.

Table 1:Optimization parameters

Substrate RT Duroid

5870

Epsilon 2.33

Tangent loss 0.0012



Width of the patch

(W)

27mm

a


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Length of the patch

(L)

17.7mm

L1 6.3mm

Gap (G) 2.15mm

Width of the

Conductor (W2)

4.5mm

L2 8.6mm

Via radius 0.6mm

W3 0.2mm

L3 10mm

EFFECTS OF DIFFERENT SLOTS WIDTH

Simulation Results

Fig 12Effects of different width wg


the simulated return loss on loss Y axis and frequency on X axis, The Width of the slot

determine the bandwidth and return loss and frequency starts from 4.50 GHz to 5.10 GHz band

so Optimized width is 0.2 is taken

Fig 13 Return loss of proposed antenna


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PLOT COMPARISON

Fig 14 Return loss of Existing and

proposed antenna

The frequency range from 2 to 12 GHz is shown in the figure 14. The above plot shows the

simulated return loss on loss Y axis and frequency on X axis.Existing antenna bandwidth of 450

MHz (4.65 GHz to 5.10 GHz) and proposed antenna is 600 MHz (4.50 GHz to 5.10 GHz)

Radiation pattern

Fig 15 Radiation pattern of Proposed antenna

The above plot(fig15) shows that 3D radiation pattern of the Modified traditional antenna at 4.9

GHz, it provides gain of 7.421 dB

CONCLUSION

In this work, we examined a Microstrip patch antenna (MPA) and the use of lambda/4

resonator and via structure on the feedline to help improve the bandwidth and suppressed

harmonic reduction. These proposed antenna structure’s simulation is carried out using the CAD

software Microwave Studio in Computer Simulation Technology Simulator (CST), one

commercial 3-D full-wave electromagnetic simulation software. Existing antenna shows that

bandwidth is about 450 MHz (4.65 GHz to 5.10 GHz). We have also analysed Return loss,

VSWR (Voltage standing wave Ratio), Radiation patternin existing antenna and proposed


347

antenna. We introduced slots at ground structure to improve the overall bandwidth and width of

the slot which directly controls the bandwidth and the optimized parameters have set as 0.2mm.

Proposed antenna shows that 600 MHz (4.50 GHz to 5.10 GHz).we have obtained excess of 150

MHz bandwidth it will cover overall performance of antenna

7. REFERENCES

[1] Ahmed A. Kishk,Kai Fong Lee, W. C. Mok, “A Wide-Band Small Size Microstrip Antenna

Proximately Coupled to a Hook Shape Probe,”Proc. IEEE Transactions on Antennas and

Propagation, vol.52,No.1,January 2004.

[2] Chen and Y.-L. Luo,“Compact filtering antenna using CRLH resonator and defected ground

structure,”Proc. ELECTRONICS Letters,vol.52,No.21,October 9 2014.

[3] C. L. Mak, K. M. Luk, K. F. Lee, and Y. L. Chow, “Experimental Study of a Microstrip

Patch Antenna with an L-Shaped Probe,”Proc. . IEEE Transactions on Antennas and

Propagation, vol.48,No.5,May 2000.

[4] Gordon Mayhew-Ridgers, Johann W. Odendaal, and Johan Joubert, “Efficient Full-Wave

Modelling of Patch Antenna Arrays With New Single-Layer Capacitive Feed Probes,”Proc.

IEEE Transactions on Antennas and Propagation, ,vol.53, No.10,October 2005.

[5] H. Wang, X. B. Huang, and D. G. Fang, “A Single Layer Wideband U-Slot Microstrip Patch

Antenna Array,”Proc.

IEEE Antennas and Wireless Propagation Letters,vol.7,2008.

[6]M. Preethi, G. Shobana, P. ThangaNandhini, M. Sheriff and M. AntoBennet “Design of Tl

Shape Rectangular Patch Antenna for Global Positioning System (GPS) Applications”, Middle-

East Journal of Scientific Research, Volume 24 ,408-413, May 2016.

[7]S. Sankaranarayan, Dr.M. AntoBennet, G. Vishaka, R. Vimala, S. Ashwini “Design of Dual

Band Pattern Diversity Antenna with RFSR”, Advances in Natural and Applied Sciences,

Volume 10 (Issue06):182-188, May 2016 .

[8]. Sankaranarayan S., AntoBennet M., Vishaka G., Vimala R., Ashwini S., Kaushik Krishna R

and Jayaprakash “Design of Tunable Dual-band Antennas for a Carrier Aggregation Systems”,

International Journal recent scientific Research, Volume 07 (Issue04):9974-9978, April 2016

[9]R.KaushikKrishna,G.SankarBabu, Dr.M.AntoBennet, G.Vishaka,J.JelcinRenis,

B.S.JayaVignesh, M.Dinesh Kumar “DESIGN OF KOCH FRACTAL WITH OCTAGONAL

SHAPED SUBSTRATE ANTENNA FOR SUPERWIDEBAND APPLICATION”, International

Journal of Applied Engineering Research, Volume 10, Number 87 (2015) pp. 44-47, December

2015.

[10]Sankara Narayanan S., Vaishally K., SathyaSubbuLakshmiS., H ariPriya E and AntoBennet

M “Doable Rate of Spectrum Sharing Cognitive Radio Multiple-Antennas Channels Using

Water Filling Power Allocation Algorithm”, International Journal recent scientific Research,

Volume 07 (Issue04):9867-9871, April 2016..


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