A HIGHLY EFFICIENT AND LINEAR INVERTED DOHERTY POWER AMPLIFIER WITH UNSYMMETRICAL DELAY PATH

A highly efficient and linear inverted Doherty power amplifier (IDPA) with unsymmetrical delay path is presented. To compensate the phase difference between carrier and peaking cells, an additional offset line is inserted at the input path of the carrier cell. For verification, the IDPA with unsymmetrical delay path is implemented using two 50-W Si LDMOSFETs and tested using a continuous wave (CW) and a one-carrier wideband code division multiple access (WCDMA) signals at 2.6 GHz. From the measured results, the proposed IDPA shows not only an increase in the gain and the power-added efficiency, but also superior adjacent channel leakage ratios improvement. After the digital predistortion linearization, the proposed IDPA shows better improved linearity than conventional IDPA, and also meet the linearity requirement of the WCDMA signal without decreasing efficiency. (C) 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1302-1305, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25962