%0 Journal Article %A Yang, Li %A Gómez García, Roberto %T Two-layered microstrip diplexer based on high-selectivity wideband bandpass filters %D 2022 %U http://hdl.handle.net/10017/51670 %X This paper presents a microstrip diplexer based on two high-selectivity wideband bandpass filters (BPFs) in a twolayered structure. Both the lower and upper channels are designed with third-order microstrip-to-microstrip vertical transitions using open-circuit-ended slotline stepped-impedance resonators (SIRs). Specifically, open-circuit-ended microstrip lines on the top and bottom layers for the lower channel are employed, whereas the upper channel is equipped with short-circuit-ended ones. Thus, owing to the slotline SIRs, two close-to-passband transmission zeros (TZs) leading to sharp-rejection capabilities for both BPF channels are attained. The theoretical foundations and RF operating principles of the devised diplexer are discussed in detail. For practical-validation purposes, a two-layered microstrip wideband diplexer prototype is designed, simulated, and tested. It features two three-pole high-selectivity filtering responses for the measured lower and upper channels that are centered at 1.52 GHz and 2.76 GHz, and exhibit 3-dB fractional bandwidths of 60% and 24.93%, respectively. %K Bandpass filter (BPF) %K Diplexer %K High selectivity %K Microstrip filter %K Multilayered circuit %K Vertical transition %K Wideband filter %K Telecomunicaciones %K Telecommunication %~ Biblioteca Universidad de Alcala