artificial materials applied to planar antenna...metamaterials are materials of non-natural...

Forum for Electromagnetic Research Methods and Application Technologies (FERMAT)

Artificial Materials applied to planar antenna

Dorsaf OMRI and Taoufik AGUILI

Syscom Laboratory, National Engineering School of Tunis,Tunisia

Biography

Dorsaf Omri received the Master degreein Mathematics from Faculty ofMathematical, Physical and NaturalSciences of Tunis and the MSc degree inCommunicationtechnologiesfrom theCommunicationtechnologiesfrom the

National Engineering School of Tunis.In 2010, she received the PhD degree in Information andCommunication Technologies and Sciences from theNational Engineering School of Tunis.Her research interest is in the field of electromagneticmodeling and time domain numerical methods.

Syscom Laboratory, National Engineering School of Tunis,Tunisia2

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Ameliorate the performance of planar antenna is the object of many research worksto allow their integration in the telecommunication systems. In recent years,Metamaterials or composite artificial materials have attracted a lot of interest in manyapplications particularly the miniaturization of antenna.

Metamaterials are materials of non-natural properties, introduced by Pendry, in2000. In fact, there are various types of metamaterials: materials with a negativepermittivity and permeability called “left-handed” or “negative refractive index”,materials of infinite impedance, material with high permeability…

Abstract

In this work, we use two artificial materials:1. The artificial material of high permeability to miniaturize a planar antenna. The

structure of this material is composed of a substrate and a Split Ring Resonator(SRR)

2. The material with a negative permittivity and permeability to ameliorate thedirectivity of a planar antenna. The structure of this material is composed of asubstrate, a Split Ring Resonator (SRR) and a wire.


3

Keywords: Directivity, High permeability, Metamaterial, Miniaturization, Planar antenna,Negative-index, SRR, Wire.

Effective parameters characterizing the artificial material

Application of the homogenization procedure to replace theparameters of the periodic artificial material by a materialcharacterized by an effective permittivity and permeability.

Transmission-reflection on a material of thickness d and of effective parametersεeff and

µeff


4

a1 a2

b1 b2

=

1

1

2221

1211

2

2 b

a

TT

TT

b

a

Transfert MatrixT

Matrix S


=

2

1

2221

1211

2

1 a

a

SS

SS

b

b

−=

)cos()sin(

)sin()cos(

nkdnkdz

k

nkdk

znkd

T

Matrix S

Material with index n and thickness d:

=

++

)(

)(

)(

)(

zH

zET

dzH

dzEr

r

r

r


5

Matrix S

)sin()1

(2

)(2

)(21

2112

1221

11

nkdzz

iik

TikT

iT

ikTik

T

rS

s

−=

+−

−==

)sin()1

(2

)cos(

1

)(21

1

2112

12

nkdz

zi

nkd

ik

TikTT

tS

s

+−=

++==


Matrix S

)sin()1

(2

)(2

)(21

2112

1221

22

nkdzz

iik

TikT

iT

ikTik

T

rS

s

−=

+−

−==

)sin()1

(2

)cos(

1

)(21

1

2112

21

nkdz

zi

nkd

ik

TikTT

tS

s

+−=

++==

sTTT == 2211


6


Effective index)

2t

tr1arcos(

kd

1n

22

eff

+−=22

22

eff t)r(1

t)r(1Z

−−−+=

"'t)r(1)2t

tr1arcos(nzµ

2222

µµ i+=

−+

+−

==

Effective impedance

"'t)r(1

t)r(1

kd

)2tarcos(nzµ

22eff µµ i+=

−−−+

==Effective permeability

d: the thickness of material k : the wave number

r: the reflection coefficientt: the transmission coefficient

22

22

22

)1()1(

)21cos(

tr

trkd

ttrar

Z

neff

−−−+

+−

==εEffective permittivity


7

Negative-index metamaterial

+ =

Material with negativepermeability

Split Ring ResonatorSRR

straight wiresNegative-index

metamaterial

Materials with negativepermittivity


8

Straight wire


plasma oscillation frequency


Effective Index

9

Negative-index metamaterialE

ffec

tive

par

amet

ers

char

acte

rizi

ng th

e st

raig

ht w

ire

Effective Permittivity

10

Eff

ecti

ve p

aram

eter

s ch

arac

teri

zing

the

stra

ight

wir

e


Effective Permeability

10

Negative-index metamaterialSplit Ring Resonator

SRR

11Syscom Laboratory, National Engineering School of Tunis,Tunisia

11

Effective Index

11

Negative-index metamaterialE

ffec

tive

par

amet

ers

char

acte

rizi

ng th

e SR

REffective Permittivity

12

Eff

ecti

ve p

aram

eter

s ch

arac

teri

zing

the

SRR



12


Association of SRR and wire


1313

Negative-index metamaterialEffective Permittivity


14


14


Index


1515

Application: Planar antenna


1616

Used the negative index metamatrial above the antenna (without losses)

dε=µ=-3.38


l

Paramters« d » and « l »


17

L=d=h/8

L=h/8 and d=h/4

Antenna Radiation Patterns

Directivity for d and l are close

Not directional

L=h/4 and d=2h

Not directional antenna

Change of directivity for

L=d/2L=h/4 and d=2h


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Adaptation of anetenna ( –27 dB) the resonationfrequency is 8.5 GHz (for l=d=2h)


19

� Directional antenna

� The gain is higher


19

Structure of artificial material with highpermeability

A periodic artificial material characterized by a magneticresonance without thepresence of the magnetic component:

�a succession of cells.�the unit cell dimensioned for the waveband [5 GHz; 15 GHz] andcomposed

of:• a RogersRO4003substratewith a permittivity equalto 3.38 and heightequalto• a RogersRO4003substratewith a permittivity equalto 3.38 and heightequalto

0.81 mm• a copper planar element: one square or two squares

Split-Ring Resonator (SRR)


20


SRR with a square

SRR with two squares


21



Effective parameters of SRR with one square resulting from the procedure of homogenization: (a) Effective Permeability (µeff) ; (b) Effective Index (neff)

(a) (b)


22



Effective parameters of SRR with two squares resulting from the procedure of homogenization: (a) Effective Permeability (µeff) ; (b) Effective Index (neff)

(a) (b)


23

Application: Miniaturization of a planarantenna

�Square patch of length L�Substrate: Rogers RO4003�h=0.81mm�εr = 3.38�tgδ = 0.0027� Groundplane: aperfectelectricconductor(PEC)� Groundplane: aperfectelectricconductor(PEC)

n

1

εµ

1

εµ2

λ

2

λL 0 =∝==

µ L


24


(a) (b)(a) (b)

(c) (d)

The reflection coefficient S11 for: ε=3.38 : (a) µ=2; (b) µ=4; (c) µ=8; (d) µ=10


25


F=8.5GHz

F=5.1GHz


Planar antenna

26


F=8.5GHz

F=3.1GHz


Planar antenna

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The SRR associated to straight wires are used to obtain a negativeindex. Also for a particularly bandwidth, the SRR admits highpermeability value.

In this work, we used an artificial material in order to ameliorate theplanar antenna performances. Then, we determined the effectiveparametersfor an elementary cell based on the homogenization

Conclusions

parametersfor an elementary cell based on the homogenizationprocedure.

Using the metamaterial with negative index above the planarantenna,we obtain for some parameters a directional antenna.

Using the periodic artificial materials, composed of elementary cells,the planar antenna are miniaturized. The artificial material was used as asubstrate.


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[1] Eleftheriades G. V., and Balmain K. G. “Negative-refraction metamaterials: fundamentalprinciples and applications.” John Wiley & Sons, 2005.

[2] Pendry J. B., Holden A. J., Robbins D. J., and Stewart, W. J. "Magnetism from conductorsand enhanced nonlinear phenomena."IEEE transactions on microwave theory andtechniques, 1999, vol. 47, no 11, p. 2075-2084.

[3] Hsu Y. J., Huang Y. C., Lih, J. S., and Chern J. L. Hsu, Yi-Jang, et al. "Electromagneticresonance in deformed split ring resonators of left-handed meta-materials." Journal ofapplied physics, 2004, vol. 96, no 4, p. 1979-1982.

[4] Alici K. B., and Özbay E. "Radiation properties of a split ring resonator and monopolecomposite." Physica status solidi (b), 2007, vol. 244, no4, p. 1192-1196.

REFERENCES

composite." Physica status solidi (b), 2007, vol. 244, no4, p. 1192-1196.[5] Smith D. R., Vier D. C., Koschny T., and Soukoulis C. M "Electromagnetic parameter

retrieval from inhomogeneous metamaterials."Physical review E, 2005, vol. 71, no 3, p.036617.

[6] Smith D. R., and Pendry J. B. "Homogenization of metamaterials by field averaging."JOSAB, 2006, vol. 23, no 3, p. 391-403.

[7] Hou Z. Z., Li X. X., and Hao C. K. "Design of wideband filter using split-ring resonatorDGS." Parameters (dB), 2008, vol. 21, p. S11.

[8] Maslovski S. I., Ikonen P. M., Kolmakov I., Tretyakov S. A.,and Kaunisto M.“ Artificialmagnetic materials based on the new magnetic particle: Metasolenoid.”Progress InElectromagnetics Research, 2005, vol. 54, p. 61-81.


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artificial materials applied to planar antenna...metamaterials are materials of non-natural...

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