Compact UWB Bandpass Filter with Narrow Notch-Band and Wide Stop-Band

Abstract

This paper presents a compact ultra-wideband (UWB) band-pass filter (BPF) with a sharply rejected notch-band and wide stop-band. The proposed UWB BPF is realized by cascading two interdigital hairpin resonator units, a spiral slot, a semicircle defected ground structure (S-DGS) and a semicircle stepped-impedance shunt stub (S-SISS). The spiral slot is studied and adopted to introduce a notched band. An S-DGS and an S-SISS are cascaded in order to suppress the spurious in stopband. Good insertion/return losses and high out-of-band rejections are achieved as demonstrated in both simulation and experiment.