Ultra-wideband (UWB) bandpass filter with three transmission zeros in the notched band

Abstract

A compact ultra-wideband (UWB) bandpass filter (BPF) with three transmission zeros in the notched-band is presented in this paper. A dual coupled microstrip/coplanar waveguide (CPW) structure with slotlines on the bottom are used. The notched-band is generated by a pair of small U-shaped slot-line on the bottom layer and a hollow microstrip resonator on the top layer, and three transmission zeros are achieved at frequency 5.85GHz, 5.9GHz, 5.95GHz without extra circuit size. The UWB bandpass filter (BPF) has been designed, fabricated and measured. The measured results agree with the simulated result closely.