Separately-designable diplexer with multiple transmission zeroes using common stub-loaded SIR

Abstract

A separately-designable diplexer with multiple transmission zeroes (TZs) using common stub-loaded stepped impedance resonator (SIR) is proposed. The common stub-loaded SIR operating in third harmonic (f3) and fifth harmonic (f5) is used for designing the two diplexer channels. The stub is loaded at the voltage-null point of f3 of the SIR. It can separately control f5 but has no effect on f3 so that the two channels can be separately designed. Meanwhile, the input port is tap-connected to the common stub-loaded SIR, which necessarily produces a TZ between f3 and f5, existing in both channel filtering responses. By properly choosing coupling schemes of the two channels, more TZs are realized at the desired locations. Thanks to the generation of the multiple TZs, both passband selectivity and isolation between the two channels are improved significantly. For demonstration, a diplexer operating at 2.22 and 2.95 GHz is designed, fabricated, and measured. The simulated and measured results are presented, showing good agreement.

Compact microstrip diplexer design using new octagonal resonators for 5G and Wi-Fi applications

“…Plus, UBS presents the upper band-stop of the diplexer. As depicted in this table, the suggested diplexer has compact size compared to [11,18,19,21,22], and exhibits good return losses and highest isolation compared with [18,20,23], while insertion losses could be ameliorated in [11,19,21,22]. Plus, the present diplexer has good upper stop-band as compared to [20].…”

Design of a Miniaturized Microstrip Diplexer Based on Hairpin and Short Stub for 5G and Wi-Fi Communications

“…2 compares our designed diplexer to other diplexers mentioned in the literature. As seen, the presented diplexer has low insertion losses in both channels compared to [5,10,13,20,21,24] and high isolation compared to [6,10,13,22,23]. Furthermore, compared to [5] and [20], the proposed diplexer has a smaller size of 30 × 25 mm 2 .…”

A Survey on microstrip filters, diplexers, and triplexers state of art between 2018 and 2022

“…The configuration showed significant gains in isolation between ports, channel isolation, and stopband rejection compared to its predecessor design. A diplexer with multiple tunable (TZs) that share a common stub-loaded resonator SIR has been presented in [32]. Multiple TZs are created to increase selectiveness and isolation between the two channels.…”