'Institute of Electrical and Electronics Engineers (IEEE)'
Abstract
Efficient and linear power amplifiers (PA) are an
essential part of forthcoming 5G wireless systems. Outphasing
class-E PAs offer high power efficiency and an option for
higher efficiency cellular networks. However, they employ
signal component separators, which split the signal into two
paths. In order to efficiently recombine the signal, nonlinear
power combiners are used. This paper proposes a novel
phase-only predistortion technique for outphasing class-E PAs.
The predistortion coefficients can be extracted based on AMAM
characteristics of the output signal and an analytical model of
an outphasing Class E PA. The suggested technique has been
validated by simulation of an outphasing power amplifier in
ADS Ptolemy software. It is shown that applying this technique
to a 16QAM OFDM modulated signal with 20 MHz bandwidth
improves error vector magnitude (EVM) from 10.39% to 2.43%
compared to the signal without predistortion
