Extending high‐efficiency power range of symmetrical Doherty power amplifiers by taking advantage of peaking stage

Abstract

In this study, a methodology is proposed for extending the high-efficiency power range (HEPR) of symmetrical Doherty power amplifiers (DPAs). This method takes advantage of the output impedance of peaking stage. Traditional symmetrical DPAs maintain high efficiency over a 6 dB power range with an assumption of the output impedance of peaking stage being infinity. This study reveals that the HEPR can be further enhanced by tuning the output impedance of peaking stage away from infinity and changing the phase delay of the impedance inverter after carrier power amplifier. A 2.2–2.3 GHz symmetrical DPA with an HEPR of 9 dB is fabricated to validate our theory. The experimental results possess drain efficiencies of 45.3–49.5% at 9 dB output power back-off level and 62.9–71% at peaking power level over 2.2–2.3 GHz. The maximum output power of the fabricated DPA is 45 dBm with a gain of 11.6–13.5 dB across 2.2–2.3 GHz.