The subject matter described herein relates to various antenna element configurations, antenna array configurations, their operations including various systems and methods to generate modulated data for transmission by an RF antenna array via an optical processing engine. The subject matter includes optical processing engine structure and methods (e.g., modulating in the optical domain, MIMO and spatial modulation via RF beam formation, coherent transmission of RF signal components, coherent operation of spatially separate RF antenna arrays) that may be implemented with the various RF antenna array structures. In some examples, the system combines the virtues of digital, analog and optical processing to arrive at a solution for scalable, non-blocking, simultaneous transmission to multiple UE-s. Much of the system architecture is independent of the RF carrier frequency, and different frequency bands can be accessed easily and rapidly by tuning the optical source (TOPS). In some examples, multiple communication channels may be transmitted simultaneously to different locations. The transmitter may be formed by an array of optically fed antennas.