Radiation from defected ground plane PBG structures

Hi all,

We all know that periodic pattern of defects(slots) in the ground plane of a microstrip line produces the PBG response of band-reject. Now it is also known that slots in the ground plane of a microstrip radiate (slot antenna). For proper operation of the PBG in a ciruit we need to ensure that radiation in minimized. My question is how to calculate the resonant frequency of a slot in a microstrip ground plane ? There must be some closed form formulas available. for a slot antenna. All help in this regard is appreciated.

-Arun

I am also interested with this topic. Does anyone has the related articles or opinion?