电子科技大学：《近代天线理论 Modern Antenna Theory》课程教学资源（课件讲稿）拓展02 EBG结构 Electromagnetic Band Gap Structure in Antenna Application

Electromagnetic Band Gap Structure in Antenna Application

Electromagnetic Band Gap Structure in Antenna Application

Introduction 1-D 2-D 3-D periodic in periodic in periodic in one direction two directions three directions ● ● ● ●

Introduction

One dimensional structure <<入 2/4 One dimensional dielectric structure One dimensional metal structure ● ●

One dimensional dielectric structure One dimensional metal structure One dimensional structure

Two dimensional dielectric structure Ψ Square lattice with dielectric columns ● ● Air column in a substrate

Square lattice with dielectric columns Air column in a substrate Two dimensional dielectric structure

Two dimensional metal structure ● ●

Two dimensional metal structure

Two dimensional single layer metal structure 米丽 a ! - ●

Two dimensional single layer metal structure

EBG structures can be used... As high impedance surface (restrain surface waves) As antenna's reflector (artificial magnetic materials) As antenna's slipcover (enhance gain,reduce RCS) Antenna array (restrain mutual couple) As TEM wave guide(magnetic wall) As resonator (High Q) As filter and phase shifter ●

As high impedance surface (restrain surface waves) As antenna’s reflector (artificial magnetic materials) As antenna’s slipcover (enhance gain, reduce RCS) Antenna array (restrain mutual couple) As TEM wave guide (magnetic wall) As resonator (High Q) As filter and phase shifter … EBG structures can be used…

Surface Wave X eax X>0 TM wave 81 Z 2 erx X<0 E1 =(2+212)ejwt-jkz-0x E12=E2: E2=(E2a+2E2z)ejwt-jkz+r 6E1x=82E2x ● ● ●

x x z z E E E E 1 1 2 2 1 2     TM wave Surface Wave

k= 81e2 ⊙ V 1+82 c E w = V 1+8c 0 61=1,62=e 0= -1w Ve1+82 - -62 W 81+e2c ● ●

     1 2 1

A).Dielectric Surface If s>0,then a and y are imaginary Simply plane wave propagate through the dielectric interface If &0 81 Z 2 erx X<0

If   0, then  and  are imaginary A). Dielectric Surface Simply plane wave propagate through the dielectric interface If   -1,or  is imaginary, the and  are positive The wave is bound to the surface x z X0