CPW-fed dual-mode double-ring resonators with Butterworth approximations for band-pass filter applications

The CPW‐fed configurations of dual‐mode ring resonator (DMRR) are introduced to improve the performance of the dual‐mode double ring resonator (DMDRR). To obtain low insertion loss (1.65 dB at TM110 mode and 0.91 dB at TM210 mode) and high out‐of‐band rejection level (−51.95 dB) and wider band (BW 13.09% at TM110 and 16.14% at TM210 mode) filters, using voltage‐couples and dual‐mode perturbations are proposed here. Simulation results including surface current distributions and frequency responses are presented and discussed. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1217–1221, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22397