Open AccessExtended‐stopband microstrip lowpass filter using rat‐race directional couplers
Author(s) -
GómezGarcía R.,
SánchezSoriano M.A.,
SánchezRenedo M.,
TorregrosaPenalva G.,
Bronchalo E.
Publication year - 2013
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.2012.4245
Subject(s) - stopband , microstrip , cutoff frequency , low pass filter , passband , band stop filter , filter (signal processing) , transition band , electronic engineering , physics , prototype filter , topology (electrical circuits) , engineering , band pass filter , optics , electrical engineering
A class of microstrip lowpass filter (LPF) with a sharp‐rejection, ultra‐broad stopband is reported. It employs rat‐race directional couplers properly arranged to operate as bandstop transversal filtering sections (TFSs). The theoretical foundations of this LPF approach are described, and the performance control of its building bandstop TFS is verified. Moreover, a proof‐of‐concept microstrip LPF prototype with a 3 dB cutoff frequency of 1 GHz and a 20 dB stopband up to 5.86 GHz has been built and tested.