%0 Journal Article 
%A Yang, Li
%A Gómez García, Roberto
%T Multilayer microstrip closely-spaced-channel wideband diplexer with highly-selective fourth-order filtering responses
%D 2022
%@ 1549-7747
%U http://hdl.handle.net/10017/51787
%X 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.
%K Bandpass filter (BPF)
%K Diplexer
%K Microstrip filter
%K Multilayer circuit
%K Multiplexer
%K RF/microwave circuit
%K Transmission zero (TZ)
%K Vertical transition
%K Wideband circuit
%K Telecomunicaciones
%K Telecommunication
%~ Biblioteca Universidad de Alcala