RF-DAC-based PA Pre-Distortion using Expanding Non-Linear RF-DAC Scaling

Paper in proceeding, 2024

We present an RF-DAC-based transmitter that uses an expanding characteristic to linearize the PA. Implemented in 22nm FDSOI CMOS, the transmitter operates with a carrier frequency of 12.5 GHz, achieving a sample rate of 7 GS/s. Measurements with >3.5 GSym/s wideband modulated 64QAM SC and OFDM signals show EVMRMS <3.83% and ACPR <−32.4 dBc when using the RF-DAC-based predistortion. The 1 dB compression point is increased by 4.2 dB. For multi-GHz wideband modulated signals, a >0.6 percent unit EVM improvement and a >2.5 dB ACPR improvement are observed.