Gerhard, W.; Knöchel, R. (University of Kiel, Microwave Laboratory, Kaiserstrasse 2, D-24143 Kiel, Germany)
Design considerations for outphasing power amplifiers (PA) are presented concerning the preferable choice of the PA class of operation (B, F) and the impact of the behavior of the PAs as real voltage sources on the combiner’s linearity for Chireix power combining . The achievable linearity and efficiency for application in WCDMA base stations is investigated. The performance of two different transistor technologies (Si-LDMOS, GaN-HEMT) in outphasing amplifiers is compared by simulations. GaN HEMTs deliver excellent output power back off (OPBO) efficiency and higher linearity and outperform LDMOS transistors at 2.14GHz.