Design of bandpass–bandpass diplexers using rectangular-, T-, and L-shaped resonators for hybrid power amplifier and 5G applications

In this paper, two bandpass–bandpass diplexers, based on L-, T- and rectangular-shaped resonators are designed and analyzed, which are used to design a novel hybrid power amplifier (HPA) in 5G applications. By using the designed diplexers, the presented hybrid power amplifier structure can operate at two desired frequencies in two desired classes of operation. The equivalent circuits and transfer functions are extracted to study the behavior of the filters responses.Query However, the proposed analysis can be used to locate transmission zeros at desired frequencies, which can ease the design procedures of the diplexers at any desired frequency. The proposed HPA and diplexers are designed at 1.5 GHz and 2.1 GHz operating frequencies. To verify the results, one of the proposed diplexers is fabricated, in which the obtained measured results are in good agreement with the simulated results. The insertion losses for the fabricated diplexer are less than 0.7 dB and the isolation value is achieved better than 27 dB in the operating frequencies. The overall sizes of the proposed diplexers are about (0.165λg × 0.198λg) and (0.75λg × 0.07λg). The results of the designed HPA show that the proposed HPA has desirable specifications. The drain efficiency (DE) and power added efficiency (PAE) of the proposed HPA are 60% and 53% at 1.5 GHz operating frequency while, the DE and PAE are 65% and 51.5% at 2.1 GHz respectively.