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Summary: 3848 IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 54, NO. 11, NOVEMBER 2006
High-Efficiency Envelope-Tracking W-CDMA
Base-Station Amplifier Using GaN HFETs
Donald F. Kimball, Member, IEEE, Jinho Jeong, Member, IEEE, Chin Hsia, Paul Draxler, Member, IEEE,
Sandro Lanfranco, Walter Nagy, Kevin Linthicum, Lawrence E. Larson, Fellow, IEEE, and
Peter M. Asbeck, Fellow, IEEE
Abstract--A high-efficiency wideband code-division mul-
tiple-access (W-CDMA) base-station amplifier is presented using
high-performance GaN heterostrucutre field-effect transistors
to achieve high gain and efficiency with good linearity. For high
efficiency, class J/E operation was employed, which can attain up
to 80% efficiency over a wide range of input powers and power
supply voltages. For nonconstant envelope input, the average
efficiency is further increased by employing the envelope-tracking
architecture using a wide-bandwidth high-efficiency envelope
amplifier. The linearity of overall system is enhanced by digital
pre-distortion. The measured average power-added efficiency
of the amplifier is as high as 50.7% for a W-CDMA modulated
signal with peak-to-average power ratio of 7.67 dB at an average
output power of 37.2 W and gain of 10.0 dB. We believe that this
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