COMPACT MICROSTRIP BANDPASS FILTER USING MODIFIED STEPPED-IMPEDANCE HAIRPIN RESONATOR

摘要

A modified compact stepped-impedance hairpin resonator using an interdigital capacitor and its application to a bandpass filter design are presented. In comparison to the coupled line of a conventional stepped-impedance hairpin resonator, the interdigital capacitor of the proposed resonator achieves a bigger parallel capacitance. Hence, the proposed resonator can achieve a compact size and a wider harmonic- free bandwidth. Comparing the measured results of the two bandpass filters using the conventional resonators or the modified resonators suggests that the bandpass filter using the proposed resonators achieves a superior performance.