Microwave planar band-pass filters using defected ground microstrip structures [articol]

Abstract

In this paper a study of some microwave microstrip band-pass filters using defected ground structures (DGS) is presented. It is shown that the presence of a slot in the ground plane can substantially enhance the electric coupling, or the electric part of a mixed coupling between two microwave resonators. This technique allows designs of tight couplings without the necessity of using very narrow coupling gaps. Based on the results of this study, a 4-pole cross-coupled planar microwave band-pass filter (BPF) with a slot in the ground plane was designed. Compared to a similar microstrip filter without defected ground, its simulated performances indicate some advantages.