Novel designs for microwave filter

Abstract

The higher frequency limit of communication systems is continually being pushed to reap its rewards: higher antenna gain, more bandwidth, and higher capacity. This project deals with microwave filters, one of the most important devices to realize such system.

Current applications require even more stringent requirement for filters: higher performance, smaller size, lighter weight, and lower cost. This project aims to design new microwave filters that meet the requirements. There are two new designs: one based on Defected Ground Structure concept, and the other based on design of equivalent circuit.

Literature survey was done to find the new ideas. The filters were designed by using simulation software; evaluating how each structural change affects the performance. The best design was fabricated and measured to verify the simulation results. It turned out that they agree closely.

The results show that the new designs satisfy above requirements. The fabricated filter is about as small and as light as SGD 0.5 coins. Moreover, the material used was one of the cheapest around. It shows good performance and easy configuration, a table of which is compiled in the conclusion.

This project shows a potential for generalization by using equivalent circuit concept. The Defected Ground Structure concept can be further analyzed to explore its potential.