Manipulation of circular polarised electromagnetic waves by artificialperiodic structures (Invited Paper)

Zelenchuk, D., & Fusco, V. (2015). Manipulation of circular polarised electromagnetic waves by artificial periodicstructures (Invited Paper). Paper presented at The Exeter Microwave Metamaterials Meeting, Exeter, UnitedKingdom.

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Download date:25. May. 2021

Overview

September 2004

Manipulation of circular polarised

electromagnetic waves by

artificial periodic structures

D. Zelenchuk, and V. Fusco

December 8, 2015

Circularly polarised wave

RHCP wave

LHCP waveThe hand is defined from the point of view of the source

|𝐸𝑥| = |𝐸𝑦| 𝜑𝑦 − 𝜑𝑥 = ±𝜋

2

Outline

• Spectral selectivity: CP frequency

selective surfaces

• Beam forming: Conical beam generation

with rotational phase shift

• Polarisation selectivity: circularly

polarised selective surface (CPSS)

Motivation

o Frequency selective surfaces (FSS) remain a key

component of satellite antenna feeding sub-systems

o They provide low-loss filtering and beam-splitting

capacity that allows using single antenna for multi-

band operation

o FSS is dual-polarisation or even circular polarisation

(CP) properties

o Properties of the dielectric stack utilised to support

printed FSS structure becomes crucial for successful

design

Specification

Ku-band Ka-band

Frequencies

(GHz)

11.7-12.75 17.3-20.2

Losses (dB) Reflected

<0.25dB

Transmitted

<0.25dB

Rejection

(dB)

30 dB N/A

Axial Ratio

(dB)

0.25 0.25

45 degree angle of incidence!

CP FSS

Γ𝑖 = −1

1 + 2𝑍𝑐 𝑍0

Γ𝑐𝑇𝐸 = Γ𝑐

𝑇𝑀

Air-filled design

Ku-band Reflection Ka-band Transmission

Manufactured material stack

Material stack inside the structure

Full-wave simulation of the

FSS with different stack

Measured results:

Substrate only

10 15 20 25-70

-60

-50

-40

-30

-20

-10

0Reference

Frequency (GHz)M

agnitude(d

B)

Rvv sim

Rhh sim

Rvv meas

Rhh meas

There is a notable difference between the

measured results and simulation of the

material stack

Measured results

εr =1.02 0 00 1.05 00 0 1.05

tan δ =0.007 0 0

0 0.012 00 0 0.007

Measured results:FSS10 15 20 25

-40

-30

-20

-10

02face

Frequency (GHz)

Magnitude(d

B)

Tvv sim

Thh sim

Tvv meas

Thh meas

10 15 20 25-40

-30

-20

-10

02face

Frequency (GHz)

Magnitude(d

B)

Rvv sim

Rhh sim

Rvv meas

Rhh meas

0 5 10 15 20 250

10

20

30

40

50

60

Frequency (GHz)

Axia

l ra

tio(d

B)

2face

Meas T

Meas R

Sim T

Sim R

0 10 200

1

2

Conical beam applications

• Conical beam antennas have omnidirectional

radiation pattern in azimuth and a notch in the

normal direction

• “Exotic” applications :

– Data transfer by free-space modes with

non-zero orbital angular momentum

– Vortex coronography, where object is in

the “shadow” of much brighter one

Conical beam generation

spiral phase plate

helicoidal dish sectorial spiral reflector

Spiral phase plate

s1

llforl

s ,21

Generation of helical beam: (a) amplitude of incident Gaussian beam,

(b) spiral phase plate, (c) amplitude of resultant Laguerre-Gaussian beam.

Rotational phase shift

y' y

x'

xqr

h

t

irr

rr

y

x

rr

rrR EE

qq

qq

qq

qq

cossin

sincos

0

0

cossin

sincos

'

'

'' yx

zkji e

j

1

2

1E

zkjrjxR e

je

1

2

12'

qE

CP excitation

Half-wave plate

condition

Unit cell of the

reflecting FSS

LP analysis of reflecting FSS

8 9 10 11 12-60

-40

-20

0

Frequency (GHz)

|| (d

B)

yy

yx

xy

xx

8 9 10 11 12-200

-100

0

100

200

Frequency (GHz)

()

yy

xx

a1

R1

R3

x'

R2

R4

a2

y'

R1,mm R2,mm R3,mm R4,mm

4.7 5.9 6.8 8

a1, deg a2, deg h, mm d, mm

21 95 7.5 19

d

CP analysis of reflecting FSS

y' y

x'

xqr

-20

-15

-10

-5

0

|| (d

B)

-50 0 50-400

-200

0

200

400

qr ()

()

rcplcp

rcprcp

lcplcp

lcprcp

zkjrjxR e

je

1

2

12'

qE

8 9 10 11 12-50

-40

-30

-20

-10

0

Frequency (GHz)

|| (d

B)

lcp lcp

rcp lcp

Out Inrcp lcp

lcp lcp

10x10 array factor

0,0,2tan

0,tan

0,0,tan

),(

1

1

1

yxx

y

xx

y

yxx

y

yx

m n

nymxnykmxkjmn eAAF

)),(sinsincossin(,

qqq

Predicted array factor of the 10x10 array with

spiral phase distribution (a) amplitude, (b) phase.

Array factor of a finite array with given phase distribution.

10x10 array EM simulation

0,0,2tan

0,tan

0,0,tan

),(

1

1

1

yxx

y

xx

y

yxx

y

yx

),( nm yx

Simulated 3D bi-static RCS of the 10x10 slit ring reflectarray with

spiral phase distribution.

Manufactured sampley

x

0,0,2tan

0,tan

0,0,tan

),(

1

1

1

yxx

y

xx

y

yxx

y

yx

The reflector has been milled from a 1mm thick aluminum with

solid aluminum ground plane. The 7.5mm separation is

maintained with plastic screws.

Measurement setup

Rotating fixture

with reflector and

receiving Fermi

antenna

The setup consists of

illuminating dual-

polarized horn and

rotating fixture with

reflector and receiving

Fermi antenna

Receiving fixture

-150 -100 -50 0 50 100 150-40

-30

-20

-10

0

q ()

Radia

tion p

attern

(dB

)

10 GHz

E-plane

H-plane

Fermi antenna and its radiation pattern in E- and H-plane

Rotating fixture with the

reflector and Fermi antennaFermi antenna foam fixture

LP measurement resultMeasured results Freq: 10.4

-20 0 20-60

-40

-20

0

Radia

tion p

attern

(dB

)

q ()

Pol:xx Plane:xz

-20 0 20-60

-40

-20

0

Pol:yx Plane:yz

q ()

measured

simulated

measured

simulated

Comparison of simulated and measured radiation patterns

(normalised) when excited by a normally incident x-polarized

plane wave at 10.4 GHz.

(a) Eq for =0 and -90<q<90 (b) Eq for =90 and -90<q<90

CP measurement results

-30 -20 -10 0 10 20 30-30

-20

-10

0

(a)

q ()

Radia

tion p

attern

(dB

)

measured

simlated

(b)

Comparison of simulated and measured radiation patterns

(normalised) in plane =0 when excited by a normally incident

CP-polarized plane wave at 10.4 GHz.

Transmit-array

y' y

R1 R3

𝛼1

𝛼2

x

x'

𝜃𝑟

R2

R4

𝑡

(a) (b)

𝑡

h

Measurement setup

Unit cell

Measured radiation pattern

(a) RHCP, (b) LHCP excitation

Magnitude Phase

Polarisation selectivity (CPSS)

(a) (b)

Reciprocal symmetrical right-hand circular polarisation

selective surface: (a) – reflection, (b) – transmission.

Jones matrix formulation

𝑇𝑙𝑖𝑛𝑓

=𝑆𝑥𝑥21 𝑆𝑥𝑦

21

𝑆𝑦𝑥21 𝑆𝑦𝑦

21 =𝐴 𝐵𝐶 𝐷

𝑇𝑐𝑖𝑟𝑐𝑓

=1

2

𝐴 + 𝐷 − 𝑗(𝐵 − 𝐶 𝐴 − 𝐷 + 𝑗(𝐵 + 𝐶 𝐴 − 𝐷 − 𝑗(𝐵 + 𝐶 𝐴 + 𝐷 + 𝑗(𝐵 − 𝐶

𝑇𝑐𝑖𝑟𝑐𝑓

=0 00 𝑆𝐿𝐶𝑃,𝐿𝐶𝑃

21 𝐴 = 𝐷 = 𝑗𝐵, 𝐵 = −𝐶

RHCPSS: LP and CP Jones matrices

General case: LP and CP Jones matrices

Single SRR model

Co-polar

Cross-polar

SRRs magnetic coupling

𝐿𝑚 = 𝑘ℎ𝐿3

Coupling inductance

Twisted SRR

Unit cell

Equivalent circuit of

90 degree TSSR

1

2

C3 pC3 pL3-Lm nL3-Lm n

3

4

L3-Lm nL3-Lm nC3 pC3 p

2*Lm n2*Lm n

2*Lm n2*Lm n1

2

1

2

C1 pC1 p

C1 pC1 p

L2 nL2 nC2 pC2 p

C2 pC2 pL2 nL2 n

Fitted vs CST

RHCPSS

RO 4003C h3=0.5mm

Rohacell foam h2=5mm

RO 4003C, h1=0.5mm

Measurement RHCPSS