electrically invisible dipole and its applications...・reconfigurable espar antenna is proposed....

・ ベクト ル実効長の法則

・ ダイポールの電気的透明化

　 　 リ コンフィ ギャラブルアンテナ

　 　 アド ミ タンスの近似計算法

　 　 アド ミ タンスの規則性

ダイポールの電気的透明化とその応用

Electrically Invisible Dipole and Its Applications 飯草 恭一(Kyoichi Iigusa)　 0 6D1 3 0 1 5

2006/6/29

目次

電子電気工学科

安藤・ 廣川研究室

ベクトル実効長の法則

Law of Vector Effective Length

Electronically Steerable Parasitic Array Radiator Antenna

variable reactors

a single feed element

parasitic elements

vs

Zsjxnjxm

mutual coupling

the radiation pattern can bevaried by reactance control

small, lightweight, economical,and power-saving

[5] T. Ohira and J. Cheng, "Analog smart antennas", Adaptive Antenna Arrays, ISBN3-540-20199-8, Berlin: Springer Verlag, 2004.

x2

zsvs

x1

x3

x6

x5 x4

[im]=([Ymn]-1+diag[zs,jx1,jx2,..,jxM])-1[vs]

xm imYmn E(θ,φ)am(θ,φ)

E(θ,φ)=-j Σ imlemam(θ,φ)

lemαm, lem

(0)

Z0sinθ e-jkr

2λr m=0

M

Mathematical model

Vector Effective Lengths as Weight

Current Distribution

.

le1/le1(0)(Phase)

02468

10121416

-8000 -4000 0 4000x1 [Ω]

-180

-90

0

90

180

Phas

e [d

eg]

le1/le1(0)(Amp.)

Am

p.

-0.002

-0.001

0

0.001

0.002

0 0.25 0.5 0.75 1z/L

314Ω

Am

p.

-6366Ω

795Ω

lem/lem(0) dependence on x1

Reactance variavle rangeof 1SV287 (2.5GHz)

jx1 jx1

jx1

b1

jx1 jx1jx1

b1

jx1 jx1

b1(Phase)

02468

10121416

-8000 -4000 0 4000Ω]

-180

-90

0

90

180

x1 [

b1(Amp.)

b1(Phase)

02468

10121416

-8000 -4000 0 4000

Ω]

-180

-90

0

90

180

x1 [

b1(Amp.)

jx1

Reactances of 3 elements are varied. Reactances of 6 elements are varied.

Independance of Other Element Reactance

Amp. Amp.Phase[deg]

Phase[deg]

αm=0.0022lem (0)≒0.7L

lem = lem (0)(1-αm xm)jxm

when L≦λ/2

Reactively Loaded Dipole

im

L lem

lem=∫im(z)dz /imz

[1] K. Iigusa and T. Ohira,"A simple and accurate mathematical model ofelectronically steerable parasitic array radiatorantennas,"IEEE CCNC2004, E1, Jan. 2004.

ダイポールの電気的透明化

Electrically Invisible Dipole

variablereactor

≠ ≒xm=1/αm

open

currentdistribution

currentdistribution

z z

Electrically Invisible Dipole

im=0

im

lem=0

lem=lem (0)(1-αm xm)

lem=le(0)m(1-αmxm)

imxm

・Independant of port currrentim・Independant of the other varactor xn

when xm=1/αmalways lem=0

≒

αm depends on only the elemsnt size.

1/αm

Electrically Invisible Dipole

xm=1/αm

Im≡lemim=0

Electrical Interaction is Minimum

Im is kept to 0 independently of the other elements.

The influence to the other elements isminimum.

lem=lem (0)(1-αm xm)

00.0010.0020.0030.0040.0050.0060.0070.008

0 0.1 0.2 0.3 0.4 0.5

#0#1#2#3#4#5#6

z/L

00.0010.0020.0030.0040.0050.0060.0070.008

0 0.1 0.2 0.3 0.4 0.5

#0#1#3

z/L

Current DistributionAmp. Amp.

Electrically invisible Physical remove

#4

#1 #2

#3

#5

#6 #0

-180

-90

0

90

180

0 0.1 0.2 0.3 0.4 0.5

#2#4#5

#6

#0

#1

#3

-180

-90

0

90

180

0 0.1 0.2 0.3 0.4 0.5z/L z/L

#1

#0

#3

Moment method

Phase PhaseElectrically invisible Physical remove

Phase Current Disttribution

j/α

1.52

2.53

3.54

4.5

-180 -90 0 90 180

φ [deg]

0.5λ

1λ

0.75λ0.4λ

0.3λ

φ

0.02λ0.25λ

Gai

n [d

Bi]

L

L=

Limit Length for Electrically Invisible Dipole

j/α

φ

0.02λ

d=

0.5λ

2.1

2.14

2.18

2.22

2.26

2.3

-180 -90 0 90 180

φ [deg]

λ/4λ/64

λ/32

λ/16

λ/2Feed dipolealone

Limmit Distance for Electrically Inbisible Dipole

d

リコンフィギャラブルアンテナReconfigurable Antenna

transform toelectricallyinvisible

transform toelectricallyinvisible

Reconfigurable ESPAR antenna

(a) Element number can be varied(b) Element position can be varied(c) Frequency can be varied

y

(d) Polarization can be varied

Reconfigurable ESPAR antenna

transform to electrically invisible

アドミタンスの近似計算法Approximate Calculation Method of Admittance

j/αm

[Y'mn][Ymn]

≒

Relations between Ymn andY'mn

are expressed with αm.

Reguration of admittances

(#4)

#1 #2

#3

#5

#6 #0

-1

Y'00 Y'01 Y'02 Y'03 Y'05 Y'06Y'10 Y'11 Y'12 Y13 Y'15 Y'16Y'20 Y'21 Y'22 Y'23 Y'25 Y'26Y'30 Y'31 Y'32 Y'33 Y'35 Y'36

Y'50 Y'51 Y'52 Y'53 Y'55 Y'56Y'60 Y'61 Y'62 Y'63 Y'65 Y'66

Y 00 Y01 Y02 Y03 Y04 Y05 Y06Y 10 Y11 Y12 Y13 Y14 Y15 Y16Y 20 Y21 Y22 Y23 Y24 Y25 Y26Y 30 Y31 Y32 Y33 Y34 Y35 Y36Y 40 Y41 Y42 Y43 Y44 Y45 Y46Y 50 Y51 Y52 Y53 Y54 Y55 Y56Y 60 Y61 Y62 Y63 Y64 Y65 Y66

0 0 0 0 0 0 00 0 0 0 0 0 00 0 0 0 0 0 00 0 0 0 0 0 00 0 0 0 j/α40 00 0 0 0 0 0 00 0 0 0 0 0 0

+

-1

Admittance Matrix Relation

The admittance matrixof the array from which#4 is removed

is almost equals tothe matrix that is made removed 5 raw and 5 line from

#n

#m

#k

・・・

Ymn

#n

#m・・・

Y'mn

transform toelectricallyinvisible

removedj/αk

Relation of Admittance

[Y'mn] ([Ymn]-1+diag[0 ...0 j/αk 0... 0])-1

≒

Y'mn = Ymn + YmkYnkYkk-jαk

#k

#1#5

#4#2

#3

x

y

z

0

0.001

0.002

0.003

0.004

0.005

0.006

0.007

0.008

0.009

Y11

Y14

Y24

Y44 Y12Y23 Y11

Real(Ymn)

Y12

Y13 Y22

Y23 Y33

Y34 Y11 Y13

Y22 Y33 Y12

Y22 Y11

Momα=0.0022

=0α

#5 is removed #5,4 areremoved

#5,4,3 areremoved

#5,4, 3,are

removed

Ascertain of The Relation

#1#5

#4#2

#3

x

y

z

Y11

Y14

Y24

Y44 Y12Y23 Y11

Imag.(Ymn)

#5 is removed #5,4 areremoved

#5,4,3 areremoved

#5,4, 3,are

removed

Y12

Y13 Y22

Y23 Y33

Y34 Y11 Y13

Y22 Y33 Y12

Y22 Y11-0.005

-0.004

-0.003

-0.002

-0.001

0

0.001

0.002

0.003

0.004

Mom=0.0022

α=0α

Ascertain of The Relation

アドミタンスYmnの規則性Regulation of Admittance Ymn

x

y

z

y

#2 #3

#1

-8-6-4-202468

1012

0.1 1 10

Y11ReY11ImY12ReY12Im

Y11ReY11ImY12ReY12Im

Mom. α=0.0022

Ymn

[mΩ-1]

Y11=Y'11+Y'122/(Y'11-2Y'12-jα1)

Y12=Y'12+Y'122/(Y'11-2Y'12-jα1)

An Equilateral Triangle Arrangement

x

y

z

y#0

#1#2

#3

#4

#6

#5

#0

#1#2

#3 #4 #5

#6

Y'mn=Ymn-Y01Y10/(Y00-jα0)Y'mn-Y'm'n'=Ymn-Ym'n'

Circular Arrangement

Removed

Removed

Summary・ Electrically invisible dipole is proposed. xm=1/αm

・ Reconfigurable ESPAR antenna is proposed. element number or position, frequency, polarization

・ Relation of admittance is presented.

Y'mn = Ymn + YmkYnkYkk-jαk