High selectivity UWB bandpass filter with controllable bandwidth of dual notch bands

A technique to implement and control the bandwidth of notch bands in an ultra-wideband (UWB) bandpass filter (BPF) based on signal superposition is described. The filter is realised by employing two wideband BPFs in a parallel configuration to establish two signal paths between input/output ports. The proposed technique can substantially increase the bandwidth of the notch band by ~370% in comparison with the notch-band filter designs based on transversal signal interaction. The proposed filter exhibits a quasi-elliptical response over the span of the UWB spectrum defined by the Federal Communication Commission. The compact filter design has a size of 88.92 mm².