Design of compact microstrip UWB bandpass filter with triple-notched bands

Abstract

A new microstrip ultra-wideband (UWB) bandpass filter (BPF) with triple-notched bands is presented in this paper. The circuit topology and its corresponding electrical parameters of the basic microstrip UWB BPF are designed by modified genetic algorithm (MGA). Then, triple-notched bands inside the UWB passband are implemented by coupling a novel triple-mode stepped impedance resonator (SIR) to the main transmission line of the basic microstrip UWB BPF. The triple-notched bands can be easily generated and set at any desired frequencies by varying the designed parameters of triple-mode SIR. For verification, a new microstrip UWB BPF with triple-notched bands respectively centered at frequencies of 4.4 GHz, 5.9GHz and 8.0 GHz is designed and fabricated. Both simulated and experimental results are provided with good agreement.