Compact bandstop filter using defected ground structure (DGS)

Abstract

This paper presents a new structure to implement compact bandstop filters by employing coupled DGS resonators etched in the ground plane. The proposed bandstop filter consists of symmetrical DGS resonators with a microstrip excitation to obtain a bandstop filter response. By adjusting space S between the two DGS coupled resonators, the bandwith of the bandstop filter can be easily controlled. A bandstop filter is designed, analyzed and implemented on FR4 dielectric substrate to operate at 2GHz. The measured results are in good agreement with simulations.