5G wideband bandpass filtering power amplifiers based on a bandwidth-extended bandpass matching network

Abstract

In this paper, a 5G wideband power amplifier (PA) with bandpass filtering response is synthesized using a bandwidth-extended bandpass filter as the matching network (MN). In this structure, the bandwidth (θC) is defined as a variable in the closed-form equations provided by the microstrip bandpass filter. It can be extended over a wide range only by changing the characteristic impedances of the structure. Different from the other wideband MNs, the extension of bandwidth does not increase the complexity of the structure (order n is fixed). In addition, based on the bandwidth-extended structure, the wideband design of bandpass filtering PA is not limited to the fixed bandwidth of the specific filter structure. The theoretical analysis of the MN and the design flow of the PA are provided in this design. The fabricated bandpass filtering PA can support almost one-octave bandwidth (2–3.8 GHz), covering the two 5G bands (n41 and n78). The drain efficiency of 47%–60% and output power higher than 40 dBm are measured. Good frequency selectivity in S-parameter measurements can be observed.