Efficiency enhancement method for high-power amplifiers using a dynamic load adaptation technique

Abstract

This paper proposes a dynamic load adaptation method as an efficiency enhancement technique for high-power amplifiers. This method modifies the output load impedance of a power amplifier using a tunable impedance transformer, so that the efficiency of the power amplifier is not degraded as the power level of the output signal is changed. The tunable impedance transformer presented here consists of a quarter-wavelength transmission line with adjustable characteristic impedance. In addition, an automatic control system is used to control the tunable impedance transformer. The experimental result shows that the efficiency is improved over the entire power range and the adjacent channel leakage power ratio (ACLR) is maintained at less than -30 dBc for a 4-carrier WCDMA signal.Index Terms -Dynamic load adaptation, Efficiency enhancement, Tunable impedance transformer.

Co-design of an antenna-power amplifier RF front-end block without matching network for 2.4 GHz WiFi application

“…However, the loss in this R-L-C matching circuits degrades efficiency of the PA and increase the power consumption. Recently, in order to increase PA efficiency some researchers have successfully study various impedance matching techniques, such as Dynamic Load Modulation (DLM) [4], variable load technique using tunable matching network [5], reconfigurable matching network [6], load-pull method [7] and 2-pole bandpass filter technique [8]. However, the interstage matching circuit between the PA and antenna adds the supplementary loss in the system performance, enhances the power consumption and increases the size of the RF front-end modules.…”