Equivalent circuit modelling of spiral defected ground structure for microstrip line

Abstract

An equivalent circuit for the microstrip line with a spiral defected ground structure (DGS), which is etched on the metallic ground plane, and a parameter extraction method, are presented. The proposed spiral DGS provides steep rejection characteristics with only one spiral-shaped defect. Experimental results show excellent agreement with simulated results of the equivalent circuit and the validity of equivalent circuit modelling for the spiral DGS.