Open AccessDual‐band filter based on one single circular patch resonator with highly improved bandwidths and compact size
Author(s) -
Liu Shicheng,
Wang Xuedao,
Zhang Hanqian,
Zhang Kezhuo,
Ding Zeyu,
Zhang Gang,
Yang Jiquan
Publication year - 2020
Publication title -
electronics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.375
H-Index - 146
ISSN - 1350-911X
DOI - 10.1049/el.2020.1888
Subject(s) - passband , resonator , return loss , physics , insertion loss , bandwidth (computing) , degenerate energy levels , band pass filter , multi band device , filter (signal processing) , optics , acoustics , topology (electrical circuits) , telecommunications , computer science , engineering , electrical engineering , antenna (radio) , quantum mechanics
In this Letter, a new design of dual‐band patch filter is proposed with greatly improved bandwidth and miniaturised size based on one single modified circular patch resonator. In this design, a metallic via is introduced in the centre region of the patch to develop the modified resonant TM 01 mode (TM′ 01 mode), while two types of slot perturbations are adopted to separate a pair of degenerate modes of TM 11 (TM 11A and TM 11B ) and control another pair of degenerate modes of TM 21 (TM 21A and TM 21B ), respectively. Thus, two passbands with one transmission zero (TZ) can be attained by elaborately exploring these resonant modes (the TM′ 01 and TM 11A modes form up the lower passband while TM 11B and TM 11A modes constitute the upper passband, and TM 21B mode is responsible for the TZ). For verification, one prototype is implemented. Results indicate that the novel dual‐band filter (centred at 3.7 and 5.3 GHz) exhibits not only relative compact size (0.36 λ g × 0.36 λ g ), but also much larger 3‐dB fractional bandwidths (27 and 13%), nice return loss (better than 21 dB) and insertion loss (better than 1.0 dB), compared with other reported patch filters.