Compact UWB Bandpass Filter with a Notch Band Using Y-Stub Loaded Multiple-Mode Resonator

In this paper, a compact ultra-wideband (UWB) bandpass filter (BPF) with desired passband performance and better skirt selectivity is designed. The proposed UWB filter consists of a multimode resonator (MMR), which includes a Y-shaped stub loaded on to a half wavelength UIR coupled to the feed lines using ground slots to enhance coupling. Two even modes and one odd mode were generated within UWB band With the aid of two transmission zeros placed at both the lower and upper cut-off frequencies, good selectivity is achieved. A pair of split-ring resonators (SRRs) is placed on either side of a Y-shaped stub to get a notch band within the desired UWB band. Hence, a UWB BPF (working from 3.1 to 10.6 GHz) is demonstrated, with a notch frequency at 5.9 GHz. However, the proposed design shows the wide stopband till 18 GHz with minimum attenuation of 10 dB in all region of stopband. The proposed filter design is verified with a fullwave electromagnetic simulator.