COMPLEMENTARY PREDISTORTER IN CMOS DIFFERENTIAL POWER AMPLIFIER

Abstract

For adaptive improvement of linearity above a 12 dB PAPR for 64QAM WiMAX. a complementary feedback loop in a differential amplifier is adopted as a pre-distorter that is realized using compensate the gm(3), the third order transconductance of the differential amplifier. The power amplifier has been implemented in 0.18 mu m CMOS technology, and the chip size is 870 mu m x 1050 mu m. The proposed PA obtains the 42% efficiency at PIdB while improving the IMD by more than 10 dB above 15 dBM output power levels. It shows a gain of as much as 14.5 dB, and a return loss below -12 dB for 2.3-2.4 GHz operation. Finally, the fabricated PA complies with the spurious emission of WiMAX standards up to 22 dBm. (C) 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52L 833-836, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25062