Compact ultra-wideband bandpass filter with notch band based on the impedance matching method


In this work, a new ultra‐wideband (UWB) bandpass filter (BPF) with notch band (NB) at 5–6 GHz is presented. The design is performed using the impedance matching method based on optimization of objective function defined in the frequency range 3.1–10.6 GHz. The filter structure is composed of uniform transmission line loaded, at its center, with stepped impedance stub to generate two transmission zeros at cutoff frequencies, and uniform transmission line stub for NB purpose. The fabricated filter has a compact size of 306.17 mm2 and fulfills the UWB BPF specifications with a sharp selectivity and an efficient cancellation of two Wireless Local Area Network frequencies (5.2 and 5.8 GHz).