Dual-Input Vector-Switched Behavioral Model for Multi-Antenna Scenarios Affected by Antenna Crosstalk

Paper i proceeding, 2026

Antenna crosstalk in circulator-less multi-antenna transmitters (TXs) induces extrinsic load modulation at the power amplifier (PA) output, which interacts with PA nonlinearities and challenges conventional behavioral models. This paper presents a dual-input vector-switched (DI-VS) model that extends the dual-input memory polynomial (DI-MP) by incorporating amplitude-dependent nonlinear branches selected via a low-complexity switching mechanism. Experimental results on a GaN Doherty power amplifier (DPA) operating at 6.8 GHz demonstrate that the DI-VS model achieves up to 6 dB improvement in normalized mean square error (NMSE) and 7.7 dB enhancement in adjacent channel error power ratio (ACEPR) compared to the DI-MP at similar complexity. The model's performance limits under increasing load mismatch are further investigated through active load-pull measurements.