Analysis of Different Defect Configurations in CEBGStructures for Directive

Patterns

Arezou Edalati, Tayeb A. Denidni, and Halim Boutayeb

INRS-EMT, University of Quebec, Montreal, Canada.

CEBG principle

CEBG: Cylindrical electromagnetic band gap,

Radially and circularly periodic,

Feed in the centre,

Present pass-band and stop-band to cylindrical EM wave,

applying a defect reconfigurable directive pattern,

Defect can be create by using active element

EBG structure

CEBG Structure

Previous work: applying horn-shape defect for reconfigurable directive pattern

Advantage: 360 degree turning of the radiation pattern

draw back: need a lot of diodes (all the wires have to loaded with active element and more power supply

CEBG antenna with horn-shape defect

Lww

a Active components (ex.: Diodes)

Reconfigurable EBG structure

Solution1previous work

structure composed of discontinuous metallic wires, defects consisting of continuous wires.

Advantage: Reduction the power supply dc current by 75%

Drawback: Narrowband Number of diode is the

same

Solution 2Apply different defect configuration

Directivity of different configuration

far-field proprieties are investigated through an examination of the two-dimensional directivity

Ez is the transverse component of the total electric field in the far filed region, calculated with the FDTD method

Directivity vs. Frequency

1.5 2.0 2.5 3.08

10

12

14

16

18

Dire

ctiv

ity (

dB)

Freq(GHz)

Defect3 Defect4 Defect5

1.5 2.0 2.5 3.08

10

12

14

16

18

Dire

ctiv

ity (

dB)

Freq(GHZ)

Horn Defect 1 Defect 2

Radiation Pattern

-20

-15

-10

-5

0

0

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90

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330

-20

-15

-10

-5

0

Freq=1.3 GHz Freq=1.5 GHz Freq=2 GHz Freq=2.5 GHz Freq=3 GHz

Horn Defect 1

-20

-15

-10

-5

0

0

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90

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330

-20

-15

-10

-5

0

Freq=1.3 GHz Freq=1.5 GHz Freq=2 GHz Freq=2.5 GHz Freq=3 GHz

Defect 3

-20

-15

-10

-5

0

0

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330

-20

-15

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-5

0

Ferq=1.3 GHz Ferq=1.5 GHz Ferq=2 GHz Ferq=2.5 GHz Ferq=3 GHz

Defect 2

-20

-15

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-5

0

0

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330

-20

-15

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-5

0

Freq=1.3 GHz Freq=1.5 GHz Freq=2 GHz Freq=2.5 GHz Freq=3 GHz

Radiation Pattern

Defect 5

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-5

0

0

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330

-20

-15

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-5

0

Freq=1.3 GHz Freq=1.5 GHz Freq=2 GHz Freq=2.5 GHz Freq=3 GHz

-20

-15

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-5

0

0

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90

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330

-20

-15

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-5

0

Freq=1.3 GHz Freq=1.5 GHz Freq=2 GHz Freq=2.5 GHz Freq=3 GHz

Defect 4

Radiation Pattern

Conclusion The best defect configuration is Defect1 in term of radiation

pattern, directivity and band width

60% reduction of active element and power supply compare to Horn configuration

They have almost the same band width