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Highly selective dual‐wideband bandpass filter using quad‐mode resonators for WLAN and WIMAX applications
Author(s) -
Qiang T.,
Wang C.,
Kim N. Y.
Publication year - 2015
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.29100
Subject(s) - band pass filter , stopband , stub (electronics) , resonator , wideband , wimax , passband , insertion loss , center frequency , bandwidth (computing) , microwave , multi band device , electronic engineering , physics , fractional bandwidth , materials science , electrical engineering , optoelectronics , engineering , telecommunications , wireless , antenna (radio)
A highly selective dual‐wideband bandpass filter (BPF) using quad‐mode resonators (QMRs) is presented. The proposed QMR loaded with two folded open‐ended stubs and a T‐shaped stub exhibits not only four transmission poles but also two transmission zeros, which results in a wider bandwidth and sharper cut‐off responses. The dual‐band performance is realized with two QMRs sharing a common input and output. Four transmission zeros are found located at 2.09, 2.67, 3.18, and 4.14 GHz, with an attenuation level that is less than −20 dB. The measured center frequencies of the two operation passbands are 2.4 (WLAN) and 3.5 GHz (WiMAX), and the minimum insertion loss of the two passbands are 0.87 and 1.4 dB, with 3 dB fractional bandwidths of 17.5% and 16%, respectively. The stopband suppression is greater than 20 dB from 4.2 to 6.5 GHz. Good agreement between the simulated and measured results demonstrates the validity of the proposed BPF. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1417–1423, 2015