Amplifier Performance Limits on Dual Function Radar and Communication

Abstract

Congestion in the electromagnetic spectrum has spurred a significant body of work on the topic of spectrum sharing. One avenue of research is Dual-Function Radar Communications (DFRC), in which a single system performs both radar and communications tasks. Numerous approaches to DFRC have been proposed, but there has been no direct comparison of the efficiency with which different approaches utilize the shared array's capabilities. This paper considers the impact of amplifier nonlinearity on the performance of simultaneous dual-beam (SDB) DFRC, and how nonlinearity affects the competitiveness of SDB against alternative concepts, including timesharing and aperture partitioning. We show that SDB operation is the most efficient DFRC technique if the additional beams and out-of-band signals produced by the amplifier nonlinearity can be tolerated, and when measured by communications spectral efficiency. However, if input backoff is used to avoid these nonlinear effects, then the performance of SDB is reduced and becomes equal to that of aperture partitioning.