Simple and low‐cost tracking generator design in envelope tracking radio frequency power amplifier system for WCDMA applications. Issue 10 (1st July 2013)

• Record Type: Journal Article
• Authors: Yusoff, Zubaida; Lees, Jonathan; Chaudhary, Muhammad Akmal; Carrubba, Vincenzo; Choi, Heungjae; Tasker, Paul; Cripps, Steve C.
• Is Part Of: IET microwaves, antennas & propagation. Volume 7:Issue 10(2013)
• Page Start: 802
• Page End: 808
• Publication Date: 2013-07-01
• Subjects: code division multiple access -- gallium compounds -- III‐V semiconductors -- power amplifiers -- radiofrequency amplifiers -- target tracking -- transformers -- wide band gap semiconductors -- wideband amplifiers; tracking generator design -- WCDMA application -- simple analogue technique -- auxiliary envelope tracking -- radiofrequency power amplifier system -- AET signal tracking -- amplified envelope signal -- RFPA -- DC component -- AC component -- simple source follower amplifier -- RF broadband transformer -- drain efficiency -- peak‐to‐average envelope power ratio -- power 25 W -- noise figure 9.17 dB -- GaN; Microwaves -- Periodicals; Microwave antennas -- Periodicals; Antennas (Electronics) -- Periodicals; Radio wave propagation -- Periodicals; Microwave communication systems -- Periodicals; 621.381305
• DOI: 10.1049/iet-map.2013.0091
• Languages: English
• ISSNs: 1751-8725

Abstract

Abstract : A simple analogue technique called auxiliary envelope tracking, or AET, is presented, which is shown to be capable of improving the efficiency of a radio frequency power amplifier (RFPA). This AET signal is an amplified envelope signal that supplies the drain port of the RFPA. The concept of AET is explained and a theoretical background for the technique is presented. The main feature of this technique lies in the separation of the DC and AC components of the tracking signal. This allows for a very simple and low‐cost tracking generator design that consists of a simple source follower amplifier and an RF broadband transformer. A practical system has been implemented and the measured results are obtained for WCDMA signals. A measurement on the realised system shows a 50% improvement in the drain efficiency at average output power of 33 dBm of a 25 W GaN. This substantial improvement is achieved at a competitive WCDMA signal with peak‐to‐average envelope power ratio of 9.17 dB.