A linearized, high efficiency 2.7 GHz wideband Doherty power amplifier with Class-J based performance enhancement

Abstract

This paper outlines the approach used for the design of a high efficiency 30W Doherty power amplifier. The benefits of exploiting the inherent device nonlinearities for Class-J PA operation are discussed, specifically in the case of Doherty amplifiers. The combination of Class-J modes and internal device matching ensures high performance in a compact, cost-sensitive Doherty amplifier design. To validate the discussed theory, a simple 2.7 GHz symmetric Doherty PA was designed and fabricated, producing 30W of output power with greater than 60% efficiency at 6 dB back-off. The PA was subsequently linearized using a wideband 20 MHz LTE signal with a PAPR of 6.5 dB. For an ACPR of <;-50 dBc, 8W of average output power was obtained with a corresponding efficiency of 60%.