Impact of Emission Time Constant on the Linearizability of AlGaN/GaN HEMTs

In this paper, impact of emission time constant of trapping effects on the linearizability of GaN HEMTs-based power amplifiers is investigated by PA-DPD co-simulation and experimental tests. The results show that emission time constant has negligible impact on the ACPR performance when it is greater than 0.1 ms for signals with bandwidth larger than 5 MHz, and maximal EVM is significantly degraded when emission time constant is between 10 us and 10 ms. In order to achieve better maximal EVM performance, DPD algorithm needs to compensate long-term memory introduced by trapping effects with emission time constant from 10 ┬Ás to 10 ms.