Coherent MIMO Array Design With Periodical Physical Element Structures

Multiple-input-multiple-output (MIMO) processing is a consolidated technique in communication systems thanks to the benefits that it offers in multipath fading environments. In recent years, studies have shown how the performances of conventional phased-array radar can be improved by using the same approach. This letter illustrates how the digital beamforming (DBF) theory can be extended to include MIMO arrays. In particular, the general description of a MIMO pattern is retrieved; accordingly, two different designs are described, which are aimed at obtaining optimal angular resolution and at controlling the sidelobes of the synthetic array pattern. An experimental result of a pattern synthesis is presented in the last section of the letter.