Circuit-level design of a Four-pole Microstrip Bandpass Filter

Abstract

This thesis describes a simple, circuit-level method for creating a compact four-pole hairpin microstrip band-pass filter. It begins with the basic Chebyshev low-pass prototype and shows how that ideal design is converted into U-shaped resonators and coupling gaps on a PCB substrate.

Using AWR Microwave Office for lumped-element modeling and AXIEM for quick electromagnetic checks, the filter layout is refined until the simulated response meets the design goals. The finalized pattern is then etched onto a Rogers board, fitted with standard connectors, and measured on a calibrated network analyzer to confirm that real-world behavior follows the circuit-level predictions.

By blending theory, circuit-level simulation and straightforward fabrication and testing, this work offers a hands-on guide for engineers and students. It demonstrates how to achieve high-performance microstrip filter designs without relying on early, full-wave layouts.