Ultra small ultra-wideband bandpass filter using broadside coupled S-shape striplines with built-in tunable notched band

A novel super compact microwave ultra-wideband (UWB) bandpass passive filter (BPF) is proposed using S-shape broadside-coupled striplines. A theoretical model is presented to analyze the scattering and coupling mechanism of the suggested filter. To eliminate interference, a tunable integrated notched-band filter is also introduced using a new technique. A group delay of 0.08 ns within the passband is observed. Experiments carried out over the designed examples and the measurement and simulation results are compared. The physical volume of the filter is 1.5 mm × 1.8 mm × 1.5 mm.