Digital Predistortion for Dual Linearly-Polarized Millimeter Wave Transmitters with Cross-Polarization Interference

This paper proposes a novel digital predistortion (DPD) technique that can simultaneously eliminate the cross-polarization interference (XPI) of dual linearly-polarized (DLP) antenna and inherent nonlinearities of power amplifiers (PAs) in millimeter wave transmitters. It is achieved by cascading the XPI cancellation module and nonlinear compensation module. The coefficients of both modules can be extracted from the decomposed over-the-air (OTA) signals. To validate the proposed idea, the experiment was carried out on a dual linearly-polarized (DLP) millimeter wave transmitter, and the results have shown that the XPI and nonlinearities can be effectively mitigated.