Compact bandpass filter design using folded coupled-line resonators

Abstract

In this paper, a compact bandpass filter using folded λ/4 coupled-line resonators is presented. An accurate model is made by using an efficient analytic design approach. Equations for extraction of the equivalent parallel-coupled-line structure representing the folded-line section are developed. A simple systematic design procedure is established for filter designers. Finally, a three-pole bandpass filter for the new resonators is designed. The new folded coupled-line filter exhibits a significant reduction in footprint as compared to the conventional design. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 32–35, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20714