Title :
Extended-stopband microstrip lowpass filter using rat-race directional couplers
Author :
GoÌmez-GarciÌa, Roberto ; SaÌnchez-Soriano, M.-A. ; SaÌnchez-Renedo, M. ; Torregrosa-Penalva, German ; Bronchalo, Enrique
Author_Institution :
Signal Theory & Commun. Dept., Univ. of Alcalá, Madrid, Spain
Abstract :
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.
Keywords :
band-stop filters; low-pass filters; microstrip directional couplers; microstrip filters; transversal filters; LPF approach; bandstop TFS; bandstop transversal filtering section; extended-stopband microstrip lowpass filter; gain 20 dB; gain 3 dB; performance control; rat-race directional coupler; sharp-rejection ultrabroad stopband filter;
Journal_Title :
Electronics Letters
DOI :
10.1049/el.2012.4245
