Convergence of OAM Beams Using Time-Modulated Concentric Circular Arrays

In this paper, time modulation technique is applied to concentric circular arrays for synthesizing orbital angular momentum (OAM) beams with lower sidelobe levels. Compared with traditional concentric circular arrays, time-modulated concentric circular arrays (TMCCAs) add a high-speed RF switch to each array element. TMCCAs can simultaneously generate multiple OAM beams by periodically controlling the working state of elements. Furthermore, the genetic algorithm (GA) is exploited to optimize the switch-on duration of elements. Results show that under the condition of equal amplitude excitation, TMCCAs can successfully synthesize lower sidelobe OAM beams.