Develop compact dual‐band bandpass filters on the aluminum oxide

Abstract

AbstractFor the purpose of minimizing the dual‐band bandpass filters (2.4 and 5.7 GHz), two stepped impedance resonator structures are modified and involved in a pair of distorted coupled lines to form a compact structure.And because the designed filter is printed on the high quality factor and dielectric constant aluminum oxide ceramic substrate by the screen‐printing technique, the characteristics of the filters could be improved and the size of the filters could be minimized to only 22.2 × 12 mm2. Furthermore, the modified SIR structure can be used to tune the second resonant frequency (harmonic) for the applications of dual bands, and the modified coupled line structures can be used to excite additional transmission zeros and adjust its locations, which can improve the characteristics of the filters effectively. In this article, the optimum measured insertion loss and bandwidth for 2.4 GHz are −0.98 dB and 11.1%, respectively, and for 5.7 GHz are −1.05 dB and 10.1%, respectively. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1091–1094, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25126