A Broadband High-Efficiency Doherty Power Amplifier With Integrated Compensating Reactance

By Jing Xia, Mengsu Yang, Yan Guo, Anding Zhu. IEEE transactions on microwave theory and techniques, 2016

143 citations recorded by the source corpus.

This paper presents a high-efficiency gallium nitride Doherty power amplifier (DPA) using an integrated compensating reactance (CR) for broadband operation. With an additional quarter-wavelength transmission line integrated in the peaking amplifier output, a CR is generated to compensate the load impedance of the carrier amplifier in the low-power region and thus enhance the back-off efficiency over a wide frequency range without affecting the Doherty load modulation at saturation. For this purpose, a peaking output matching network (OMN) is employed to convert the output impedance of the peaking device into quasi-short circuit when it is off and achieve proper impedance matching when it is on. A two-point matching technique using the transmission (ABCD) matrix is employed to design such desired OMN. Measurement results show that the DPA has a 6-dB back-off efficiency of 50%-55% and a saturated efficiency of 57%-71% over the frequency band of 1.7-2.8 GHz (49% fractional bandwidth). When driven by a 20-MHz long term evolution modulated signal at 6.5-dB back-off power, the DPA can achieve an average efficiency of more than 50% with high linearity after linearization over the design frequency band.

Subfields: Condensed Matter Physics, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/684d1f42cd47c2987cdc9ae9d8aa974b703d0786