Microwave bandpass filters for multi-band communications

Abstract

This project is mainly focused on understanding of the knowledge of microstrip line and filters as well as the usage of simulation software ADS. The main objective of this research is to analyze and design a class of dual-band filters using Step Impedance Resonator (SIR) and Parallel Coupled Microstrip Line (PCML). Characterized by both theoretical analysis and simulation, the SIR and PCML are found to have several unique advantages in design of this type of filters. The SIR is made of three sections with different impedances between the middle section and the left-/right-side sections. As the PCML is properly installed in the two sides of this SIR, a dual-band filter can be constructed with varied dual-passpand performance. Follow the initial circuit-based, a few dual-band filters are successfully designed via ADS software. To further improve out-of-band rejection, a three-stage SIR dual-band filter is designed with much better in-band and out-of-band performance.