Discrete lens array optimization for MIMO communication

Continuous Aperture Phased MIMO (CAP-MIMO) is a novel transceiver architecture that combines the concept of beamspace MIMO and analog beamforming to fully exploit the advantages of high-dimensional MIMO channels with the lowest possible transceiver complexity. CAP-MIMO theory dictates that the analog beamformer affect a spatial Fourier transform. A CAP-MIMO prototype uses a discrete lens array (DLA) designed for broadside focusing, which approximates the Fourier transform well near broadside but degrades at larger angles. This paper discusses the optimization of the DLA to achieve a closer approximation to the Fourier transform over a wider angular spread. Numerical results obtained using an iterative algorithm are presented that demonstrate the more uniform performance achieved by the optimized DLA.