Design of Matching Circuits for Microstrip Triplexers Based on Stepped-Impedance Resonators

• Published in: IEEE transactions on microwave theory and techniques Vol. 54; no. 12; pp. 4185 - 4192
• Main Authors: Deng, Pu-Hua, Lai, Ming-Iu, Jeng, Shyh-Kang, Chen, Chun Hsiung
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.12.2006; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Band pass filters; Bandpass filters; Circuit properties; Circuit simulation; Circuits; Distributed parameter circuits; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Exact sciences and technology; Frequency; Frequency filters; Integrated circuit measurements; Matching; Microstrip; Microstrip resonators; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Microwaves; Multiplexing; Oscillators, resonators, synthetizers; Passband; Resonance; Resonators; RLC circuits; Short circuits; Simulation; stepped-impedance resonator; Transmission lines; triplexer; Resonator; Circuit design; Stepped impedance device; Matching circuit; Microstrip; triplexer; Short circuit; Transmission line; Spurious signal; Circuit matching; stepped-impedance resonator; Band pass filter; Microstrip circuits
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2006.886161

New matching circuits for microstrip triplexers are proposed based on half-wavelength tapped-connected (or fed) stepped-impedance resonators. The stepped-impedance resonators play important roles for the matching circuits, either to serve as a through pass at the center frequency of a bandpass filter or to provide a short circuit at the center frequency of another bandpass filter. First, three tapped-connected stepped-impedance resonators together with suitable branch transmission lines are utilized to develop the matching circuits for a microstrip triplexer. The design procedure for these matching circuits is much simpler than that for the conventional triplexer structures due to the use of tapped-connected stepped-impedance resonators. Second, to reduce the number of stepped-impedance resonators and to improve the spurious resonances associated with the proposed matching circuits, modified matching circuits for the triplexer are also proposed. Agreement between measured and simulated results is observed and supports the usefulness of the design procedure