The Impact of Phase Distortion on Simultaneous RF Emissions from an Array

Signal interference constraints and limited RF spectrum space have made it necessary to further study ways of addressing the coexistence of radar and communications systems. In this work, we build on prior research towards simultaneous emission of multiple RF signals from a common array. We study the impact of non-linearities in power amplifiers on the resultant emitted wavefront, specifically the impact of non-linear phase distortions on the coherence of the emitted wavefront. To do this, we examine the strength of radiation in the space orthogonal to the two transmit signals, and the strength and location of the focused beams carrying the two desired signals. We show that phase distortions do not appreciably affect signal power in each of the intended transmit directions, nor of emissions orthogonal to the radar or communications transmit signals, but that communications throughput (as measured by BER) is impacted by those phase distortions. Finally, we show that digital pre-distortion is sufficient to overcome the effects of phase distortion.