New design of compact dual band‐notch ultra‐wideband bandpass filter based on coupled wave canceller inverted T‐shaped stubs

The procedure of attaining a compact bandpass filter (BPF) with dual band‐notch function for ultra‐wideband (UWB) applications is presented and discussed. In the proposed BPF, defected ground structure is used in order to improve the out‐of‐band performance of the filter. Also, four short‐circuited bent stubs are employed in order to improve the selectivity of the filter at its cutoff frequencies. Dual band‐notch function is added to the performance of the filter by coupling two short‐circuited inverted T‐shaped stubs to the filter main resonator. The fabricated filter satisfies well the demands of the Federal Communications Committee with two narrow band‐notch functions at 5.5 and 8 GHz, which eliminates the interference of the UWB system with wireless local area network (WLAN) and satellite communication systems, respectively. The improved upper stop‐band of the proposed filter with more than 20 dB attenuation level extends up to 20 GHz.