A linearity-enhanced compact series-type doherty amplifier suitable for CDMA handset applications

초록

A high-linearity series-type Doherty amplifier that does not use bulky 3dB quadrature hybrid coupler is developed for mobile handset applications. A predistorter is employed at the input to improve the ACPR performance at the high-power region, which effectively extends maximum linear power range. For size and stability considerations, the phasing circuits between the carrier and peak amplifiers have been realized using high-pass T-networks. The series-type Doherty amplifier of this work shows PAE’s of 18 % and 42.8 % at 16 dBm and 28 dBm, while meeting the IS-95A ACPR requirement of -42 dBc.