Analysis of Non-linear Power Amplifier Effect and Digital Predistortion on OFDM Radar

Abstract

Orthogonal frequency division multiplexing (OFDM) radars are impacted by the power amplifier (PA) non-linearity, due to the high peak-to-power-average ratio of the radar waveform, as in OFDM communication systems. In the state-of-the-art, solutions using digital pre-distortion (DPD) and symbol-based equalization have been proposed to try to mitigate the impact of PA distortions. However, the effect of PA non-linearity on range sidelobes was not detailed, especially when guard bands (GBs) are included in OFDM subcarriers. In this paper, we provide a detailed analytical signal model of the PA non-linearity impact on OFDM radar considering GBs. A method to combine constant amplitude zero autocorrelation code with DPD is validated by simulations.