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Stepped impedance hairpin design of a tunable bandpass filter with harmonic suppression
Author(s) -
Chen YuWei,
Ho MinHua
Publication year - 2006
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.21447
Subject(s) - passband , insertion loss , stopband , band pass filter , resonator , harmonics , microwave , materials science , bandwidth (computing) , electrical impedance , electronic engineering , center frequency , electrical engineering , engineering , optoelectronics , telecommunications , voltage
Stepped impedance hairpin resonators (SIHRs) with harmonic suppression and capability of frequency tuning are incorporated into a bandpass filter design. A tapped‐in U‐shaped feed structure is introduced to suppress harmonics and to reduce the passband insertion losses. The passband flexibility is accomplished by using a pair of tuning varactors. A simple method to implant a zero in the frequency response is also studied herein to further deepen the passband skirt. A 176% (4.32 GHz) stopband bandwidth is observed under more than 20‐dB band rejection. A measured minimum insertion loss of 1.19 dB is observed for the circuit with absence of the tuning varactors. Using the varactors, this filter has achieved a 22% frequency tuning range with all the insertion losses less than 5 dB. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 697–701, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21447