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

|This paper focuses on designing and manufacturing a compact microstrip diplexer, which operates at 3.5 GHz and 5 GHz for 5G and Wi-Fi applications, respectively. Indeed, two bandpass (cid:12)lters are combined to create the proposed diplexer. For making bandpass (cid:12)lters compact, a hairpin resonator is suggested and developed into an E-shaped resonator. To attain the central frequencies, a short microstrip stub loading the E-shaped resonator is proposed. The (cid:12)lters were combined by a coupling junction to form the (cid:12)nal diplexer. The proposed diplexer exhibits good isolation that is better than 40 dB in the whole operational frequency band. Additionally, the passband insertion losses are about 1 dB, and the return losses are about 20 dB and 26 dB at the two channels, respectively. Moreover, the (cid:12)nal size of the manufactured diplexer is 30 (cid:2) 25 mm 2 (0 : 6 (cid:21) g (cid:2) 0 : 52 (cid:21) g ). These results con(cid:12)rm that the suggested diplexer is suitable for the demanded applications.