A microstrip‐line phase shifter constructed by a tunable filter

A phase shifter configuration based on a bandpass filter that can change the phase continuously is discussed. In this configuration, the phase change due to resonance is used by making variable the center frequency of a filter with a broad passband. The configuration consisting of varactor diodes loaded on a microstrip line filter with short-circuited stubs to decrease the insertion loss is studied in detail by analysis and experiment. The possibility of application to a phase shifter is verified. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 90(2): 25– 32, 2007; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/ecjb.20253