Sharp rejection UWB bandpass filter with notched band

A novel ultra-wideband (UWB) bandpass filter (BPF) structure is presented. The presented structure consists of two quarter-wavelength coupled-line series in the centre position and two quarter-wavelength shorted coupled-line shunts on both sides. The new UWB structure shows the multiple-mode resonant characteristic and two shunt shorted coupled-lines can provide two transmission zeros on both sides of the passband. As a validation, a microstrip UWB BPF was designed and fabricated. Sharp and deep rejection is achieved on both the lower and the upper stopband. In addition, a notched band is designed at 8.0 GHz for a rejecting satellite communication signal. The measurement results agree well with the full-wave EM simulated responses.