Hardware and Processing Architecture Impacts on Adaptive Beamforming in Digital Phased Arrays

Typical approaches to receive digital beamforming (DBF) have used antenna array architectures wherein large numbers of elements are combined via fixed radio frequency (RF) manifolds into a small number of digital channels. These channels can then be used to adaptively cancel interference within limits pertaining to the number of digital channels relative to the number of interference sources and hardware considerations such as channel-pair cancellation ratio (CPCR). Emerging technologies promise new flexibility through array architectures that can potentially be digitized at or nearly at the element level. This enables the adaptation of the processing architecture to specific modes or functions and varying RF interference environments and the use of larger numbers of spatial degrees of freedom (DoFs) than has previously been practical. In this paper, we show the development of an ideal (ensemble average) covariance model for adaptive DBF that incorporates the effects of dispersion and channel mismatch and consider the impact of CPCR on ADBF performance in the context of channel and beamspace processing architectures.