A Compact and Symmetric UWB Bandpass Filter using Stepped Impedance Resonator (SIR) and Defected Ground Structure (DGS)

In this paper, a compact and symmetric Ultra-Wide Band Bandpass filter (UWB-BPF) is designed on a low loss RT Duroid 5880 substrate. The proposed filter is constructed by stepped impedance resonator (SIR) on the top side and defected ground structure (DGS) in the bottom. The ground plane is etched by circular patch, square and vertical slots to enhance the performance of the filter. Simulations are carried out in HFSS software. The outcome of the filter in terms of 3 dB bandwidth is about 8 GHz covering the frequency range from 2 to 10.1 GHz with a Fractional bandwidth of 106.7%. From the filter response, it is observed that the filter is highly selective with two transmission zeros and three attenuation poles at 3.6 GHz, 6.7 GHz and 8.7 GHz. The parametric analysis of the filter with variation in structural parameters is also presented.