Two-Stage GaN HEMT Amplifier With Gate–Source Voltage Shaping for Efficiency Versus Bandwidth Enhancements

Author

Ramadan, Alaaeddine ; Reveyrand, Tibault ; Martin, Audrey ; Nebus, Jean-Michel ; Bouysse, Philippe ; Lapierre, Luc ; Villemazet, Jean-François ; Forestier, Stéphane

Author_Institution

XLIM Lab., Univ. of Limoges, Limoges, France

Volume

59

Issue

3

fYear

2011

fDate

3/1/2011 12:00:00 AM

Firstpage

699

Lastpage

706

Abstract

In this paper a two-stage 2-GHz GaN HEMT amplifier with 15-W output power, 28-dB power gain, and 70% power-added efficiency (PAE) is presented. The power stage is designed to operate under class F conditions. The driver stage operates under class F^-1 conditions and feeds the power stage with both fundamental and second harmonic components. The inter stage matching is designed to target a quasi-half sine voltage shape at the intrinsic gate port of the power stage. The goal is to reduce aperture angle of the power stage and get PAE improvements over a wide frequency bandwidth. In addition to the amplifier design description, this paper reports original time-domain waveform measurements at internal nodes of the designed two-stage power amplifier using calibrated high-impedance probes and large signal network analyzer. Furthermore, waveform measurements recorded at different frequencies show that aperture angle remains reduced over large frequency bandwidth. In this study, a PAE greater than 60% is reached over 20% frequency bandwidth.

Keywords

UHF power amplifiers; gallium compounds; high electron mobility transistors; network analysers; GaN; amplifier design description; bandwidth enhancements; calibrated high-impedance probes; class F conditions; efficiency 70 percent; frequency 2 GHz; gain 28 dB; gate-source voltage shaping; interstage matching; intrinsic gate port; power 15 W; power amplifier; power stage; power-added efficiency; quasihalf sine voltage shape; second harmonic components; signal network analyzer; time-domain waveform measurements; two-stage HEMT amplifier; Aperture angle; GaN power amplifier (PA); classes F and ${hbox{F}}^{-1}$ ; power-added efficiency (PAE); waveform measurements;

fLanguage

English

Journal_Title

Microwave Theory and Techniques, IEEE Transactions on

Publisher

ieee

ISSN

0018-9480

Type

jour

DOI

10.1109/TMTT.2010.2095033

Filename

5669365