Realization of dual notch bands in UWB bandpass filter using two T-shaped resonators

Abstract

An ultra-wideband (UWB) bandpass filter with dual notch bands using a short-circuited T-shaped resonator and an inner T-shaped resonator is proposed. It is based on the filter of microstrip lines and rectangular patch multiple mode resonator with inner rectangular slot. The proposed filter using a short-circuited T-shaped resonator coupled to the main transmission line of the basic BSF to achieve the low-frequency resonance at 3.3 GHz and using an inner T-shaped resonator to achieve the high-frequency resonance at 5.2 GHz. The proposed BSF has passband from 2.9 to 10.6 GHz with sharp rejection skirts outside the passband and its insertion loss is less than 0.8 dB over the entire frequency band. The design parameters is optimized by 3D EM commercial software HFSS 13.0, and the simulation results indicated that the proposed filter can generate two notch bands at 3.3 GHz and 5.2 GHz. The proposed filter can efficiently reduce the interference from undesired signals at 3.3 GHz in WiMAX and at 5.2 GHz in WLAN with certain application prospects.