A New Compact Dual Band Microstrip BPF for GSM (1.8GHz) and WiMAX Using Asymmetric Stepped Impedance Resonators

Abstract

We propose a design of a compact dual-bandpass microstrip filter (DBPF) for the GSM (1.8 GHz) and WiMAX (3.4 GHz) application using asym-metric SIRs. The presented filter has very low insertion loss (S 21) and high selec-tivity for the desired band. Appearance of transmission zeroes near the edges of passband in the proposed design guarantees sharp cut off frequency and improves the selectivity of proposed band pass filter with fractional bandwidth (FBW) of 10 and 7.08 %.The proposed filter has low insertion losses, (S 21) −0.24 and 0.14 dB and the return losses, (S 11) −14.71 dB and −25.01 dB for the center frequencies 1.8 GHz and 3.4 GHz, respectively.