Search

This paper analyses the impacts of the harmonic-tuned hybrid continuous modes (HTHCMs) approach on the back-off efficiency of Doherty power amplifiers (DPAs). Based on the HTHCMs strategy, formulations are derived for designing the impedance inverting network (IIN) and impedance transforming network (ITN) in the DPA. Via the proposed approach, multiple impedance solutions for realizing broadband DPAs with substantial output back-off efficiency recovery is made possible. The potentiality of the design method is demonstrated by the realized prototype working from 1.4 to 2.45 GHz. Test results have shown over 50% drain efficiency at 6 dB back-off power. [ABSTRACT FROM AUTHOR]

A 0.4–2.3 GHz broadband power amplifier (PA) extended continuous class-F design technology is proposed in this paper. Traditional continuous class-F PA performs in high-efficiency only in one octave bandwidth. With the increasing development of wireless communication, the PA is in demand to cover the mainstream communication standards’ working frequencies from 0.4 GHz to 2.2 GHz. In order to achieve this objective, the bandwidths of class-F and continuous class-F PA are analysed and discussed by Fourier series. Also, two criteria, which could reduce the continuous class-F PA’s implementation complexity, are presented and explained to investigate the overlapping area of the transistor’s current and voltage waveforms. The proposed PA design technology is based on the continuous class-F design method and divides the bandwidth into two parts: the first part covers the bandwidth from 1.3 GHz to 2.3 GHz, where the impedances are designed by the continuous class-F method; the other part covers the bandwidth from 0.4 GHz to 1.3 GHz, where the impedance to guarantee PA to be in high-efficiency over this bandwidth is selected and controlled. The improved particle swarm optimisation is employed for realising the multi-impedances of output and input network. A PA based on a commercial 10 W GaN high electron mobility transistor is designed and fabricated to verify the proposed design method. The simulation and measurement results show that the proposed PA could deliver 40–76% power added efficiency and more than 11 dB power gain with more than 40 dBm output power over the bandwidth from 0.4–2.3 GHz. [ABSTRACT FROM PUBLISHER]