%0 Journal Article 
%A Yang, Li
%A Malki, Mohamed
%A Muñoz Ferreras, José María
%A Gómez García, Roberto
%T Balanced quasi-elliptic-type dual-passband filters using planar transversal coupled-line sections and their digital modeling
%D 2022
%@ 1759-0787
%U http://hdl.handle.net/10017/55350
%X A class of balanced dual-band bandpass filters (BPFs) with planar transversal-signal-interference coupled-line sections is reported. In their building balanced dual-band BPF stage under differential-mode excitation, a second-order quasi-elliptic-type dual-band bandpass filtering transfer function is obtained. Specifically, from the transversal interaction among their two open-ended and virtually-short-ended half-wavelength coupled-line paths, sharp-rejection differential-mode dual passbands with several out-of-band transmission zeros at both sides are realized. To attain high common-mode suppression levels within the differential-mode passbands, two open-ended line segments are connected at the symmetry plane of the devised balanced dual-band BPF stage. Moreover, higher-order schemes based on in-series-cascaded multi-stage designs to further increase differential-mode selectivity and in-band common-mode rejection are illustrated. The operational principles and parametric-analysis design rules of the engineered transversal-coupled-line-based balanced dual-band BPF approach are detailed. Additionally, for a rigorous interpretation of their zero/pole characteristics, a digital-modeling framework is applied to them to connect RF balanced filters with their discrete-time versions. For practical-validation purposes, a microstrip prototype of two-stage/fourth-order balanced dual-band BPF is built and tested. It exhibits measured differential-mode dual passbands with center frequencies of 1.464 GHz and 2.294 GHz, 3-dB fractional bandwidths of 8.74% and 9.68%, and in-band common-mode rejection levels above 23.16 dB and 31.36 dB, respectively.
%K Balanced filter
%K Bandpass filter (BPF)
%K Dual-band filter
%K Microstrip filter
%K Parallel coupled line
%K Planar filter
%K Signal-interference filter
%K Transmission zero (TZ)
%K Transversal section
%K Telecomunicaciones
%K Telecommunication
%~ Biblioteca Universidad de Alcala