Compact microstrip low-pass filter with wide stop-band using P-shaped resonator

Abstract

This paper, a compact low-pass filter (LPF) with an Elliptic function response using P-shaped resonators is presented. The LPF with simple structure results in the low insertion loss less than 0.1 dB and high return loss better than 20 dB, in the passband. The proposed filter with a -3 dB cutoff frequency of 2.61 GHz is fabricated and measured. The measured results show that the proposed LPF has significant advantages such as a wide stopband from 2.9 GHz to 17.3 GHz with the suppression level better than -20 dB, and it has an acceptable sharp frequency response in the transition band. The measurement results are in good agreement with the simulation results.