Open-stub based spurious harmonic suppression method for Microstrip Coupled Line Filter

TL;DR

This paper presents an innovative open-stub based method to suppress spurious harmonics in microstrip coupled line filters, enhancing filter performance through a novel design approach validated by simulations.

Contribution

The paper introduces a new open-stub technique for spurious harmonic suppression in microstrip filters, combined with an analytical design method based on image impedance.

Findings

Effective suppression of spurious harmonics demonstrated in simulations

Design approach simplifies filter synthesis with improved harmonic performance

Validated band pass filter design shows practical applicability

Abstract

In this paper, first, we review a straightforward analytical technique based on image impedance concept for designing traditional microwave microstrip coupled line filters using distributed elements. In the introduced approach, we characterize a quarter-wave coupled line section, and then these discrete sections can be connected in series to synthesis the final desired frequency response. Next, we use a novel open-stub based technique to suppress spurious harmonic frequencies. Finally, using proposed technique, we design and simulate a band pass filter (BPF). The simulation results prove the usefulness of the proposed technique.