Performance Evaluation and Optimization of stepped impedance and stub-based low-pass filter for S-Band applications

Abstract

Wireless Communication is an integral part of modern communication systems. Microwave filters play a vital role in mobile and wireless communication systems. Microwave filters are used in most wireless communication systems having RF-front end for performing various signal processing tasks such as frequency selection, suppression of mixers unwanted intermodulation products etc. This paper presents the optimized design of low-cost microstrip technology based S-band low-pass filters using two different design topologies like: stepped impedance and stub-based filters. Low-pass filters of order N=5 are designed, optimized and simulated using the ADS tool to achieve minimum insertion loss (S21) in pass-band and attenuation greater than 20dB at 3.5GHz.Consequently, optimized filters are manufactured and tested using Vector Network Analyzer (VNA) for S21 parameter of device under test (DUT) . Finally, comparison of post simulation and measured results are carried out for the proposed filters.