Offline and Time-variant EVD-based Closed-loop Digital Predistortion Design for Sub-THz Power Amplifier Array in Basedband Transmitter

In this paper, we propose an eigenvalue decomposition (EVD) based digital predistortion (DPD) design for nonlinear memory PAs in active antenna array structure with offline and time-variant scenario. The simulation environment incorporates various non-ideal effects based on IEEE Std 802.15.3d, the transmitter error vector magnitude (TX EVM) performance can be improved from -9.07dB to -20.64 dB in the presence of the proposed DPD. Furthermore, since the characteristics of the sub-THz power amplifiers are sensitive to temperature changes, we simulate the impact when the temperature rises from 27 °C to 125°C. This leads to inaccurate offline estimation, while with the proposed online tracking mechanism, the TX EVM can be improved from -13.34 dB to -20.05 dB. For the hardware implementation, we use 16-nm FinFET CMOS process with eight times parallelism architecture to achieve a data transmission with a bandwidth of 7.04GHz. The core area and power are 0.106 mm2 and 464.8 mW for the TX DPD, and 0.0576 mm2 and 252.0 mW for the receiver optimizer, respectively.