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