Open AccessFiltering rat‐race couplers with impedance transforming characteristics based on terminated coupled line structures
Author(s) -
Dong Gaoya,
Wang Weimin,
Wu Yongle,
Liu Yuanan,
Tentzeris Manos M.
Publication year - 2020
Publication title -
iet microwaves, antennas and propagation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.555
H-Index - 69
eISSN - 1751-8733
pISSN - 1751-8725
DOI - 10.1049/iet-map.2019.0631
Subject(s) - stopband , passband , rat race coupler , band pass filter , electrical impedance , transformer , electronic engineering , fractional bandwidth , hybrid coupler , power dividers and directional couplers , topology (electrical circuits) , computer science , engineering , electrical engineering , voltage
In this study, a series of rat‐race couplers with bandpass filtering responses and impedance transforming characteristics are presented based on novel coupled‐line structures. Firstly, a novel filtering rat‐race coupler core circuit is proposed by introducing coupled‐line structures into conventional rat‐race coupler. Then, a series of rat‐race couplers with enhanced filtering responses and stopband rejections are constructed by employing various types of impedance transformers. The even‐ and odd‐mode methods are adopted to explain the operating mechanisms. Finally, a filtering rat‐race coupler prototype with a fractional bandwidth of 35.2% is designed and measured. The measured results show high passband selectivity, good out‐of‐band rejection and isolation performances, which is attractive for practical application.