Characterization of linear power amplifiers for LTE applications

Paper in proceeding, 2018

This paper compares the performance of and analyzes the linearity metrics with different signals for two linear PAs: A single-ended class-AB PA and a linear Doherty PA (DPA). Both PAs utilize the 6 W GaN HEMT CGH40006P at a design frequency of 3 GHz for the class-AB PA and 3.5 GHz for the DPA. Different linearity metrics are studied for a 5-MHz spaced two-tone signal and a 5-MHz Long Term Evolution signal. The DPA has a power added efficiency of 40% whereas the class-AB PA shows 27% given a-40 dBc linearity constraint on the closest adjacent channel (ACPRi). The class-AB PA, however, exhibits better linearity in terms of ACPR2. It is additionally shown that the trends of the linearity metrics for the different signals differ for the two architectures.