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Compact tri‐band BPF design using spur‐line‐loaded tri‐section SIRs
Author(s) -
Lee ChingHer,
Hsu ChungI G.,
Chen YuCheng
Publication year - 2009
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.24208
Subject(s) - passband , stopband , band pass filter , spur , insertion loss , microstrip , microwave , miniaturization , electrical engineering , wimax , physics , topology (electrical circuits) , electronic engineering , engineering , telecommunications , wireless , structural engineering
In this article, a new tri‐band microstrip bandpass filter (BPF) is proposed. The BPF is composed of two folded, rectangular‐shaped three‐section SIRs (TSSIRs) whose first three resonant frequencies can be tuned to locate in the desired passbands. The BPF are 0° fed and the end sections of the TSSIRs are designed in an antiparallel fashion to produce zeros at appropriate frequencies for improving passband selectivity. In addition, by embedding spur lines and defected ground structures (DGS) in the BPF, extra transmission zeros around the first spurious passband are introduced to widen the upper stopband. The designed BPF is fabricated on an RT/Duroid 6010 substrate. The measured fractional bandwidths (minimum insertion losses) for the 1.57 GHz (GPS), 2.45 GHz (ISM), and 3.5 GHz (WiMAX) bands, respectively, are 11.5% (1 dB), 4.6% (2.19 dB), and 10.9% (1.3 dB), which agree well with those predicted by simulation. It also shows that for miniaturization purposes, the TSSIRs are made meandered to give an overall circuit size of only 23.29 × 10.94 mm 2 for the designed BPF. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 989–991, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24208