Advances in the Design Synthesis of Electromagnetic Bandgap Metamaterials

Advances in the Design Synthesis of Electromagnetic Bandgap Metamaterials

Douglas H. Werner, Douglas J. Kern, Pingjuan L. Werner, Michael J. Wilhelm, Agostino Monorchio, and Luigi Lanuzza

OverviewOverview• EBG structures as metamaterials• Review of standard EBG design approaches• Multi-band EBG with fractal FSS elements• EBGs with electrically small unit cells• Genetic Algorithms for AMC HIGP designè Synthesis of multi-band AMC HIGPsè Synthesis of multi-band AMC HIGPs with angular

stabilityè Synthesis of meta-ferrites

• Design, fabrication, and testing of low-profile SBWB antenna on AMC HIGP

• EBG structures as metamaterials• Review of standard EBG design approaches• Multi-band EBG with fractal FSS elements• EBGs with electrically small unit cells• Genetic Algorithms for AMC HIGP designè Synthesis of multi-band AMC HIGPsè Synthesis of multi-band AMC HIGPs with angular

stabilityè Synthesis of meta-ferrites

• Design, fabrication, and testing of low-profile SBWB antenna on AMC HIGP

Human LungHuman LungHuman Lung

EBG MaterialsEBG MaterialsEBG Materials• Electromanetic Bandgap (EBG) materials• Multiband artificial dielectric meta-materials

with fractal sphere molecules• Left-handed or Double-Negative materials

(including magneto-electric coupling)• Meta-ferrite materials• Bi-anisotropic meta-materials

•• ElectromaneticElectromanetic BandgapBandgap (EBG) materials(EBG) materials•• MultibandMultiband artificial dielectric metaartificial dielectric meta--materials materials

with fractal sphere moleculeswith fractal sphere molecules•• LeftLeft--handed or Doublehanded or Double--Negative materials Negative materials

(including magneto(including magneto--electric coupling)electric coupling)•• MetaMeta--ferrite materialsferrite materials•• BiBi--anisotropic metaanisotropic meta--materialsmaterials

Electromagnetic MetaElectromagnetic Meta--materialsmaterials

Fractal Sphere SpongeFractal Sphere SpongeFractal Sphere Sponge

EBG High Impedance Surfaces

Circuit Model:

Simple parallel LC circuit can be used to represent the surface

impedance

D. Sievenpiper, L. Zhang, R. Jimenez Broas, N. Alexopolous, E. Yablonivitch, “High-Impedance Electromagnetic Surfaces with a Forbidden Frequency Band,” IEEE Trans. Antennas Propagat., vol. 47, n. 11, Nov. 1999.

L

C

Original EBG or High-Z FSS Geometry

Original Dimensions:

εr = 10.2 h = 25 mil

a = 120 mil w = 10 mil

d = 27.5 mil l = 40 mil

d

a

w

w

w

l

Substrate Ground Plane

Metal Pattern

h

F. Yang, K. Ma, Y. Qian, T. Itoh, “A uniplanar compact photonic-bandgap (UC-PBG) structure and its applications for microwave circuits,” IEEE Trans. Microwave Theory Tech., vol. 47, Aug. 1999.

20)/(1 ωω

ω

−=

LjZS

0

0

ZZZZ

S

S

+−

=Γ Ω= 3770Z

LC1

0 =ω

pFC 185.0= nHL 4.0=

Surface Impedance and Reflection Coefficient

dDielectric Slab

Impedance Sheet Zs

Ground Plane

EBG cells have multiple resonance modes originating from different portions of the cellEBG cells have multiple resonance modes originating from different portions of the cell

èWe can intentionally design an EBG for multimode behavior

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0

45

90

135

180

0 5 10 15 20 25 30 35 40 45 50

Frequency (GHz)

Pha

se A

ngle

(deg

)

Fractalized Multiband FSSReflection Phase vs. Frequency

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0

45

90

135

180

5 10 15 20 25 30 35 40 45 50

Frequency (GHz)

Phas

e (d

eg)

FSS Cell Geometry:

• dx = dy = 0.5 cm

•

• h = 0.05 cm

10 2.rε =

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-90

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0

45

90

135

180

0 5 10 15 20 25 30 35 40 45 50

Frequency (GHz)

Pha

se A

ngle

(deg

)

Original Interdigitated

Higher capacitance lowers the resonant frequency for the same

geometric footprint

Interdigitated Capacitance

Dual Band GPS and 4.0 GHz EBG

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0

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0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

FSS Cell Geometry:

• dx = dy = 1.874 cm

•

• h = 5.08 mm (0.2 in)

Optimized for Zero Phase at 1.575 and 4.0 GHz

Result shows Zero Phase at 1.575 and 4.0 GHz

13e r =

Tri-band EBG

FSS Cell Geometry:

• dx = dy = 3.4 mm

•

• h = 4.97 mm

Reflection Phase vs. Frequency

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0

50

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250

0 2 4 6 8 10 12 14 16 18 20

Frequency (GHz)

Pha

se A

ngle

(de

g)

Optimized for Zero Phase at 3, 11 and 18 GHz

Result shows Zero Phase at 3.7, 11 and 17.8 GHz

13.78er =

GA-HZ-FSS Dual-Band Design

Genetically-Optimized Dual Band EBG

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180

1 1.2 1.4 1.6 1.8 2 2.2 2.4

Frequency(GHz)

Pha

se (

Deg

rees

)

Measured Results Theoretical Simulation

FSS Cell Geometry:

• dx = dy = 2.96 cm (λ /6.4)

• er = 13

• h = 0.293 cm

Comparison of Angular StabilityComparison of Angular StabilityAngular Stability of 1.575 GHz Resonance

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20

60

100

140

0 15 30 45 60 75 90

Theta (deg)

Ph

ase

(deg

)

TE phase - original TM phase

TE phase - optimized TM phase - optimized

Comparison of Angular StabilityComparison of Angular StabilityAngular Stability of 1.96 GHz Resonance

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0

30

0 15 30 45 60 75 90

Theta (deg)

Pha

se (

deg)

TE phase - original TM phase - original

TE phase - optimized TM phase - optimized

Artificial Ferrite MetaArtificial Ferrite Meta--materials materials (Meta(Meta--Ferrites)Ferrites)

By optimizing an HZ-FSS design for the appropriate values of Rs and Xs, a high frequency artificial ferrite meta-material can be synthesized with almost any desired value of real and imaginary permeability.

By optimizing an HZBy optimizing an HZ--FSS design for FSS design for the appropriate values of the appropriate values of RsRs and Xs, and Xs, a high frequency artificial ferrite a high frequency artificial ferrite metameta--material can be synthesized material can be synthesized with with almost any desired value of almost any desired value of real and imaginary permeabilityreal and imaginary permeability..

HZ - FSS Structure Ferrite Material withPEC Ground Plane

Surface Impedance:

Dielectric Permittivity:

2s s sZ R jX= +

r r rjε ε ε′ ′′= −

Surface Impedance:

Dielectric Permeability:

1sZ Ztanh( d )γ=

r r rjµ µ µ′ ′′= −

h d0 0

sr

Xd

µω µ

′ =0 0

sr

Rd

µω µ

′′ =

•• Improved microwave components and devicesImproved microwave components and devices

•• Substrate metaSubstrate meta--materials for materials for microstripmicrostrip filters filters and antennasand antennas

•• Electromagnetic absorbersElectromagnetic absorbers

•• Electronic packagingElectronic packaging

•• EMI / EMCEMI / EMC

Vias may be omitted from EBG designsVias may be omitted from EBG designs

Finite-sized EBG modeled with & without center-patch vias

Conclusion: Ground vias may be omitted from EBGs in antenna applications, even at steep grazing angles.

Huge improvement in manufacturability and manufacturing cost (25% - 40% savings).

Antenna Patterns

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0

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10

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Theta [degrees]

Gai

n [

dB

i] No Via - Eplane (phi=0)No Via - Hplane (phi=90)Via - Eplane (phi=0)Via - Eplane (phi=90)

E-Plane Cut

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0 30

60

90

12

0

15

0

18

0

Angle [degrees]

Gai

n [d

Bi]

1.7GHz

1.8GHz

E-Plane Cut

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10

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0 30 60 90 120

150

180

Angle [degrees]

Gai

n [d

Bi] 1.9GHz

2.0GHz

2.1GHz

E-Plane Cut

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10

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0 30

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90

12

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0

Angle [degrees]

Gai

n [d

Bi] 2.2GHz

2.3GHz

2.4GHz

Measurements of SBWB (Design 1) with AntennaMeasurements of SBWB (Design 1) with Antenna

H-Plane cut

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0 30

60

90

12

0

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0

18

0

Azimuth [degrees]

Gai

n [d

Bi] 1.6 GHz

1.7 GHz

1.8 GHz

H-Plane cut

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0

10

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-90

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0 30 60 90 120

150

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Azimuth [degrees]

Gai

n [

dB

i] 1.9 GHz

2 GHz

2.1 GHz

H-Plane cut

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0

10

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-90

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0 30 60 90 120

150

180

Azimuth [degrees]

Gai

n [

dB

i] 2.2 GHz

2.3 GHz

2.4 GHz

Measurements of SBWB (Design 1) with AntennaMeasurements of SBWB (Design 1) with Antenna