Experimental BER Performance of Quasi-Circular Array Antenna for OAM Communications
Reham M. Fouda, Amir Ebrahimi, Thomas C. Baum, Kamran Ghorbani
Abstract
Orbital angular momentum (OAM), providing an additional degree of freedom, has attracted much attention for spectral efficiency and its potential in communications. The need for more compact OAM-based communication systems has inspired research into quasi-circular arrays (QCAs) producing quasi-OAM beams. In this letter, a QCA-based communication system prototype is designed to transmit and receive quasi-OAM beams of dominant mode order l=-1, over a free-space link at 8.5 GHz. The performance of quasi-OAM beams generated by QCAs is analyzed through bit-error-rate (BER) measurements in a lab setting. The BER results are then analyzed against BER of a conventional OAM circular array and augmented quasi-OAM by a QCA to investigate their performance. Furthermore, the intermode interference is analyzed by adding mode l=0. The results indicate the feasibility of a quasi-OAM communication system, and proved to be similar, or better than conventional OAM-based systems, where there is no mode cross-talk. Augmenting OAM modes is also proven to make a quasi-OAM communication link similar to conventional OAM, in the presence of cross-talk.