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New coupled‐line bandpass filter with stepped impedance hairpin (SIH) resonator
Author(s) -
Wang YuZhen,
Her ManLong,
Chiou YiChyun,
Wu YingDe
Publication year - 2004
Publication title -
microwave and optical technology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 76
eISSN - 1098-2760
pISSN - 0895-2477
DOI - 10.1002/mop.20553
Subject(s) - band pass filter , resonator , electronic filter topology , band stop filter , bandwidth (computing) , m derived filter , electronic engineering , microwave , microstrip , physics , filter (signal processing) , materials science , optoelectronics , electrical engineering , low pass filter , engineering , telecommunications
In this paper, a new coupled‐line bandpass filter with a stepped impedance hairpin (SIH) resonator is proposed. The design formulas are derived based on coupled‐line filter theory and the equivalent‐circuit network. This filter not only achieves better selectivity, but also suppresses the 2 nd ‐harmonic response, as compared with the three‐stage parallel‐coupled microstrip‐line bandpass filter, which we use as the conventional case. The measured results show that the proposed coupled‐line bandpass filter with an SIH resonator increases the lower‐ and upper‐band selectivity by 13.8% and 41.9%, respectively. In addition, the level of the 2 nd ‐harmonic response is improved 35 dB, and the fractional 3‐dB bandwidth is reduced 10.5%. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 80–83, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20553