Design of Bandpass Filter with High Selectivity Using Stepped Impedance Resonator

Abstract

Abstract-In this paper, a novel bandpass filter (BPF) with high selectivity and great out-of band suppression is proposed by using stepped impedance resonators (SIR) and defected ground structure. The measured 3-dB bandwidth of the proposed BPF is 2.62-2.72GHz; the maximum simulated insertion loss is 0.4 dB within passband. Besides, there are four transmission zeros located at 2.12, 2.54, 2.84, and 3.80 GHz, the out-of band suppression is better than 20 dB, indicating that the proposed BPF has great suppression. Moreover, the measured and simulated filter characteristics are in agreement, which means that this design is effective. The characteristic of high selectivity is meaningful in wireless communication.