Analysis of Efficiency-Limiting Factors Resulting from Transistor Current Source on Class-F and Inverse Class-F Power Amplifiers

Abstract

This paper describes the efficiency-limiting factors resulting from transistor current source in the case of class-F and inverse class-F (F −1 ) operations under saturated region. We investigated the influence of knee voltage and gate-voltage clipping behaviors on drain efficiency as limiting factors for the current source. Numerical analysis using a simplified transistor model was carried out. As a result, we have demonstrated that the limiting factor for class-F −1 operation is the gate-diode conduction rather than knee voltage. On the other hand, class-F PA is restricted by the knee voltage effects. Furthermore, nonlinear measurements carried out on a GaN HEMT validate our analytical results.

Development and validation of a novel bias network design method for a class AB PA

“…Power amplifier (PA), as the core module of modern wireless communication system, with its performance, for example, the output power () and power added efficiency (), can greatly affect the overall performance of the entire communication systems 1–3 . Thus, in order to improve the quality of the communication system, a series of high‐performance PAs with different types of classes and topologies have been proposed over the years, such as class F, 4–7 class J, 8–10 Doherty PA, 11–15 outphasing PA, 16–18 and load modulated balanced amplifier (LMBA), 19–21 and good performance have been obtained.…”