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Tunable dual‐mode dual‐band filter with constant bandwidth and high selectivity
Author(s) -
Wu Bian,
Xu Yang,
Xia Lei
Publication year - 2017
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.30282
Subject(s) - varicap , resonator , multi band device , bandwidth (computing) , microwave , biasing , optoelectronics , dual mode , band pass filter , physics , voltage , materials science , optics , electrical engineering , electronic engineering , capacitance , telecommunications , engineering , electrode , quantum mechanics , antenna (radio)
A tunable dual‐mode dual‐band filter composed of varactor‐loaded folded square loop resonator is presented. A pair of the resonators is mirror coupled to form the higher band, while two varactors with the same bias are symmetrically loaded at the corner of each loop, splitting dual modes and form the tunable lower band. As the bias voltage increases, the lower band frequency increases from 1.1 GHz to 1.5 GHz with a constant bandwidth, while the higher band one remains at 2.1 GHz. The dual‐mode effect and source‐load coupling introduce multiple transmission zeros that effectively improves the out‐of‐band selectivity. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:283–285, 2017