A dual‐mode uniplanar bandpass filter using an inset‐coupling structure

A novel dual‐mode uniplanar square slot‐loop resonator, using an inset‐coupling mechanism with capacitive gaps is proposed. The mode splitting of the uniplanar resonator is described with respect to the perturbation size. A dual‐mode uniplanar filter using such a resonator is designed and fabricated with 5% bandwidth at the center frequency of 2.97 GHz for demonstration. The measured filter performance is presented. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 481–483, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/mop.20178