High-Efficiency Envelope-Tracking W-CDMA Base-Station Amplifier Using GaN HFETs

A high-efficiency wideband code-division multiple-access (W-CDMA) base-station amplifier is presented using high-performance GaN heterostructure 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 corresponds to the best efficiency performance among reported base-station power amplifiers for W-CDMA. The measured error vector magnitude is as low as 1.74% with adjacent channel leakage ratio of -51.0 dBc at an offset frequency of 5 MHz

[1]  F. Raab.  Intermodulation distortion in Kahn-technique transmitters , 1996 .

[2]  H. Blanck,et al.  High-voltage GaAs power-HBTs for base-station amplifiers , 2001, 2001 IEEE MTT-S International Microwave Sympsoium Digest (Cat. No.01CH37157).

[3]  C. Weitzel,et al.  RF power amplifiers for wireless communications , 2002, 24th Annual Technical Digest Gallium Arsenide Integrated Circuit (GaAs IC) Symposiu.

[4]  W. Brakensiek,et al.  Record efficiency and gain at 2.1 GHz of high power RF transistors for cellular and 3G base stations , 2003, IEEE International Electron Devices Meeting 2003.

[5]  S. Yokokawa,et al.  A 174 W high-efficiency GaN HEMT power amplifier for W-CDMA base station applications , 2003, IEEE International Electron Devices Meeting 2003.

[6]  N.B. Carvalho,et al.  Nonlinear device model of microwave power GaN HEMTs for high power-amplifier design , 2004, IEEE Transactions on Microwave Theory and Techniques.

[7]  S. Sano,et al.  A 28V 250W GaAs power FET with high gain of 15.5 dB for W-CDMA base stations , 2004, 2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535).

[8]  G. Baudoin,et al.  EER architecture specifications for OFDM transmitter using a class E amplifier , 2004, IEEE Microwave and Wireless Components Letters.

[9]  J. D. Brown,et al.  150 W GaN-on-Si RF power transistor , 2005, IMS 2005.

[10]  L.E. Larson,et al.  Design of wide-bandwidth envelope-tracking power amplifiers for OFDM applications , 2005, IEEE Transactions on Microwave Theory and Techniques.

[11]  L. Larson,et al.  50% PAE WCDMA basestation amplifier implemented with GaN HFETs , 2005, IEEE Compound Semiconductor Integrated Circuit Symposium, 2005. CSIC '05..

[12]  Feipeng Wang,et al.  An Improved Power-Added Efficiency 19-dBm Hybrid Envelope Elimination and Restoration Power Amplifier for 802.11g WLAN Applications , 2006, IEEE Transactions on Microwave Theory and Techniques.

[13]  P. Draxler,et al.  High Efficiency Envelope Tracking LDMOS Power Amplifier for W-CDMA , 2006, 2006 IEEE MTT-S International Microwave Symposium Digest.