Design of a Compact Ultra-wideband Bandpass Filter Employing Defected Ground Structure and Short-Circuited Stubs

Abstract

A compact-sized ultra-wideband (UWB) bandpass filter (BPF) comprising short-circuited stubs and defected ground structures (DGS) is presented in this paper. The BPF structure is obtained by cascading the DGS-based lowpass filter (LPF) and the optimum distributed highpass filter (HPF). The optimum BPF design provides comparatively low insertion loss and a wide attenuation band. Since the structure is compact, it improves the selectivity. The BPF is designed using the RO5880 substrate of thickness 1.57 mm, and the dielectric constant of it is er = 2.2. The average group delay calculated for the BPF is approximately 0.5 ns. The frequency response of UWB composite BPF supports the UWB range (3.1–10.6 GHz), which is suited for Bluetooth and other wireless applications.