Open AccessSix‐channel diplexer with compact size and high isolation
Author(s) -
Li Qun,
Zhang Yonghong
Publication year - 2017
Publication title -
electronics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.375
H-Index - 146
eISSN - 1350-911X
pISSN - 0013-5194
DOI - 10.1049/el.2017.2182
Subject(s) - diplexer , resonator , channel (broadcasting) , coupling coefficient of resonators , coupling (piping) , multi mode optical fiber , microstrip , electronic engineering , filter (signal processing) , transmission line , acoustics , materials science , physics , telecommunications , optoelectronics , optics , electrical engineering , engineering , optical fiber , metallurgy
A six‐channel microstrip diplexer with compact size and high isolation is presented. The six‐channel diplexer includes two pairs of multimode resonators with a pseudo‐interdigital structure and a distributed coupling feeding line. Modal characteristics of the multimode resonator are explained by the even‐odd‐mode method. The centre frequencies of channel filters can be controlled independently, while bandwidths can be determined by the coupling coefficient and external quality factor. The distributed coupling feeding line has advantages of size reduction and small loading effect. Therefore, each channel filter can be designed independently. Moreover, the distributed coupling feeding line forms the zero degree feeding structure which can bring transmission zeros to realise high isolation. Finally, a six‐channel diplexer prototype working at the centre frequencies of 1.8, 2.4, 3.0, 3.8, 4.7 and 5.8 GHz with over 30 dB isolation is fabricated and measured. Simulated and measured results show a good agreement.