Beamspace Modulated Circular Array

In this communication, we show how each independent spatial mode of a circular array (CA) can be individually encoded and collimated to yield high ergodic spectral sum efficiency of an uplink mobile communication system. We show that every mode generated with the help of Rotman lens is orthogonal to every other mode. This reduces the spatial cross coupling and thereby enhances data throughput. We also show that unlike other phased arrays, the CA has the ability to detect the direction of arrival (DOA) from the backward half-space of the array to advantage. Furthermore, we show that because of its symmetry, the array can unlike linear arrays, create beam that can be scanned over 360° in azimuth scan plane. A proof of principle multimode CA for the purpose defined above is designed, simulated, and tested.