Quad-Band Bandpass Filter Using Modified Asymmetric Stepped Impedance Resonators

This paper proposes a compact quad-band bandpass filter designed by new modified asymmetric stepped impedance resonators (SIRs). The four passbands are generated by controlling the impedance and length ratios of the traditional asymmetric and new modified asymmetric stepped impedance resonators (SIRs). The bandpass filter response is designed at 2.35, 3.8, 5.2, and 6.55 GHz, respectively. The filter can achieve compact circuit size, and it can provide multipath propagation to enhance frequency response. The measurement results are in good agreement with the full-wave electromagnetic (EM) simulation results.