Premium
A compact and high‐selectivity tri‐band bandpass filter based on symmetrical stub‐loaded square ring resonator
Author(s) -
Liu Liang,
Liang Xianling,
Jin Ronghong,
Bai Xudong,
Fan Haijun,
Geng Junping
Publication year - 2020
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.32070
Subject(s) - stub (electronics) , band pass filter , resonator , center frequency , square (algebra) , split ring resonator , wavelength , physics , optics , electronic engineering , engineering , mathematics , geometry
A compact tri‐band bandpass filter is presented in this article, whose three passbands are realized by the lowest three resonant modes of a new structure of symmetrical stub‐loaded square ring resonator. The filter features a compact size of 0.049 λ g 2 ( λ g is the guided wavelength) as well as a high selectivity with nine transmission zeros. In addition, by using the odd‐ and even‐mode analysis, its center frequencies can be easily tuned to the desired frequencies by the identical‐number parameters, namely, the lengths of short‐, open‐, and square ring‐stubs. To validate the proposed design, a tri‐band bandpass filter with center frequencies of 2.4, 3.5, and 5.2 GHz was designed, simulated, and measured. The measurement results agree well with the simulation results.