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A novel three-way distributed Doherty power amplifier, with improved efficiency at high peak-to-average ratio (PAR) signals such as W-CDMA and OFDM, is presented. This distributed Doherty amplifier consists of one main amplifier and two peaking amplifiers. In order to improve the efficiency at a high back-off power, the peaking amplifier structure is based on a dual-fed distributed amplifier form. The results of the three-way distributed Doherty amplifier, measured at 2140 MHz, produced a power gain of 11 dB. At that point, a power-added efficiency (PAE) of 39.5 percent was measured for a 9.5 dB PAR signal. A high linearity peiformance of -54 dBc ACPR is achieved after using memory-compensated digital predistortion. [ABSTRACT FROM AUTHOR]

This article provides a direct performance comparison between a Doherty digital predistorted (DPD) amplifier and a Doherty feed-forward linearized power amplifier (DFFLPA) under various crest factor reduction levels. Based on experimental results t an ACLR of -45 dBc, the DPD amplifier achieved a power efficiency of 24.5, 27 and 29 percent, compared to the DFFLPA's 17, 19.5 and 21 percent for peak-to-average power ratios of 9.8, 6.5 and 5.5 dB, respectively. [ABSTRACT FROM AUTHOR]