Design of stepped impedance resonator bandpass hairpin filter

摘要

According to the analysis of stepped impedance resonator and interdigital capacitance loading loop resonator, a design of the elliptic or quasi-elliptic bandpass filter is proposed in this paper. With the cross-coupling, the performance of filters can be enhanced greatly by introducing transmission zeros near the passband frequencies. Otherwise, the filter can change the frequency of the spurious passband with different impedance ratio of SIR. The simulation and optimization are explained with ANSOFT HFSS. Finally, a filter was designed with a center frequency at 1.4GHz, the minimum passband insertion loss is about 4.2dB, and the passband return loss is greater than 14.2dB.