What is the DGS in microstrip antenna?

dear all,

i need help about DGS in microstrip antenna, can u explain me what DGS and i need basic paper about DGS.thanks in advance

Hey heviraf,
DGS, defected ground structure in a new version, which replaces the PBG(photonic band gap) structure(very complex to design and implement). here we gonna etch an area in the ground plane under the stripline, may be in any structure. This creats a Band-Stop effect(ie S21 is reduces for particular frequecies), which have equivalent circuit of a parallel LC network.
First structure introduced in the year 2000, so it's one hot topic, which mostly useful to reduce the size of planar microwave passive circuits.
I here attached the fundamental paper..

i think this can help you