A Doherty power amplifier with extended efficiency and bandwidth

Abstract

This paper proposes a modified Doherty power amplifier (DPA) configuration for bandwidth and efficiency operations. To mitigate the efficiency degradation resulting from the incomplete load modulation network (LMN) and the knee voltage effect, the carrier transistor's optimum load impedances based on related constant voltage standing wave ratio (VSWR) circle theory are introduced. Meanwhile, a innovative LMN with broadband matching technologies is adopted, which plays a guiding role on the bandwidth expansion from the theoretical point of view. In order to verify the practical feasibility of the design scheme, two 10 W GaN HEMT transistors are used to design a broadband DPA. The measurement results show that the working bandwidth of the power amplifier is from 1.6 GHz to 2.6 GHz. The saturated output power of the whole frequency band is about 41.7-44 dBm and the drain efficiency (DE) is more than 50.8% at the input power of 33 dBm. In addition, the DE is 41.5-45% at 6-dB back-off power. Measurement results verify that the proposed enhancement techniques of bandwidth and efficiency are effective for DPA.

Design of broadband Class EF power amplifier based on low-pass filter matching structure

“…Especially for power amplifiers (PAs), the related characteristics such as bandwidth and efficiency must be greatly improved. Recently, many high-efficiency RF PAs have been reported in [3,4,5,6,7,8,9,10,11]. The traditional harmonic control PAs such as Class F PAs [12,13,14,15] and switch PAs like class E PAs [16,17,18,19] have become the research hotspots because of their ideal 100% drain efficiency.…”

A Compact Output Power Combiner for Broadband Doherty Power Amplifiers

“…The conventional broadband Doherty architecture, which uses two quarter-wave transformers, is presented in Figure 1. Broadband behavior is achieved by reducing the Impedance Transformation Ratio (ITR) for the quarter-wave line connecting the Main and Auxiliary amplifiers [7,8]. In this paper, a novel compact broadband output power combiner for Doherty Power Amplifiers is presented ( Figure 2).…”

Design of broadband high-efficiency power amplifier based on elliptic low-pass and band-pass matching network

“…In order to realize the above modes, a series of broadband impedance matching theories and techniques have been reported [7,8,9,10,11]. Particularly, classical filter design approaches are proved to be efficient [12,13,14,15].…”