Design and Simulation of Low Pass and Band Stop Microwave Filters

Abstract

The design & simulation of microwave filters such as fifth order Low Pass Filter (LPF) and Band-Stop Filter (BSF) with maximally flat (Butterworth) response is presented in this paper. The two filters were initially designed using lumped-element (LC) method. Additionally, they tested this LPF as a stepped impedance microstrip line for real-life applications as distributed element. All designs and simulations took place on Advanced Design System (ADS) software. According to simulation results, the lumped-element LPF has a cutoff frequency of 2 GHz and offers high passband rejection of 54 dB at stopband frequency of 7 GHz. The stepped impedance microstrip LPF has the same cutoff of 2 GHz and a similar filter response. Thus, there is a fair comparison between the two implementation techniques. The simulated response of the lumped-element BSF also confirms a well-defined stopband behavior from 3 GHz to 7 GHz, thereby satisfying the desired design specifications.