Multilayer microstrip closely-spaced-channel wideband diplexer with highly-selective fourth-order filtering responses
AuthorsYang, Li; Gómez García, Roberto
IdentifiersPermanent link (URI): http://hdl.handle.net/10017/51787
Agencia Estatal de Investigación
Yang, Li & Gómez García, R. 2022, "Multilayer microstrip closely-spaced-channel wideband diplexer with highly-selective fourth-order filtering responses", IEEE Transactions on Circuits and Systems II: Express Briefs, early access, DOI: 10.1109/TCSII.2022.3173910.
Bandpass filter (BPF)
Transmission zero (TZ)
info:eu-repo/grantAgreement/EC/H2020/754382/EU/GOT Energy Talent/GET
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2020-116983RB-I00/ES/NEW-GENERATION MICROWAVE PASSIVE COMPONENTS FOR ADVANCED WIRELESS-COMMUNICATIONS%2FRF-SENSING PLATFORMS/
Attribution-NonCommercial-NoDerivatives 4.0 Internacional
© 2022 IEEE
A type of multilayer microstrip diplexer with highlyselectivewidebandfiltering channels is reported. Its closely-spaced fourth-order passbands are attributed to two circuit parts: (i) two third-order quasi-elliptic-type microstrip-to-microstrip wideband vertical transitions and (ii) a shunt two-stub dual-band bandpass filter (BPF) junction printed on the top layer. The two microstrip vertical transitions are developed by means of open-/short-circuitended microstrip lines and slotline stepped-impedance resonators (SIRs), respectively, and they correspond to the constituent lower and upper channels. The shunt dual-band BPF junction produces one additional transmission pole and one more pair of close-topassband transmission zeros (TZs) for each channel to further increase their filtering selectivity. The RF theoretical foundations and design procedure of the engineered broadband diplexer are detailed. For practical-validation purposes, a proof-of-concept prototype of two-layer fourth-order microstrip wideband diplexer is simulated, manufactured, and tested. Its measured lower and upper channels has two closely-spaced sharp-rejection passbands with center frequencies of 1.496 GHz and 2.759 GHz and 3-dB fractional bandwidths of 62.83% and 24.83%, respectively, while featuring power-isolation levels above 27.39 dB from 0.5 to 4 GHz.