Achieving linearity for outphasing amplifiers targeting LTE applications and beyond

This paper analyses the impact of the level locations in a multilevel LINC transmitter on the obtainable linearity performance. Results show that by placing levels in the upper dynamic region of outphased signals, a linearity performance suitable for LTE applications and beyond can be achieved. A multilevel LINC transmitter with 5 levels is implemented using 10 W GaN CREE devices at 1.9 GHz. A 10 dB PAPR 1.4 MHz LTE signal is decomposed for outphasing and recombined to achieve an ACPR performance of -50 dBc while delivering 2 W average output power.