Premium
Design of quad‐channel diplexer adopting channel filters with impedance transformers
Author(s) -
Peng H.S.,
Cheng Y.H.,
Chiang YiChyun
Publication year - 2017
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.30421
Subject(s) - diplexer , electronic engineering , passband , microstrip , engineering , transformer , multi band device , band pass filter , resonator , electrical engineering , electrical impedance , distributed element filter , filter (signal processing) , prototype filter , low pass filter , voltage , antenna (radio)
A microstrip diplexer that uses different types of resonant structures to exhibit four channels at two different outputs is presented in this paper. A procedure for synthesizing the diplexer with two dual‐band filters having the required passband characteristics is also proposed. To reduce the interference between the filters at different outputs, the original structures of the dual‐band filters are modified by inserting embedded impedance transformers at the inputs of the lumped‐element resonators in the filters. Another component, working as an inductive compensation, is connected to the common input port to achieve the desired quad‐channel characteristics when the filters with embedded impedance transformers cannot eliminate the interference between the channel filters. To verify the proposed design method, an experimental prototype with four channels located in commonly used wireless communication bands is fabricated on a commercial printed circuit board substrate. The diplexer is highly compact; the measured insertion losses of all passbands are <2.8 dB and the associated return losses are >15 dB in the desired passbands. The isolations between the four passbands of the two outputs are all >30 dB. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:883–888, 2017