A secure high-speed retrodirective communication link

A retrodirective array with adaptive interference rejection is developed to introduce additional functionality to conventional retrodirective arrays. This is the first retrodirective array to present an interference rejection mode, creating a secure wireless communication link. The array uses digital signal processing initially and periodically to determine the location of a jamming signal and directs sub-arrays to form a null in the corresponding direction. The continuous analog self-tracking of a desired source maintains the retrodirective array's high-speed advantage over conventional smart antennas, requiring no computational algorithms for direction of arrival estimation and beamforming. It is demonstrated that interference is highly detrimental to retrodirective array performance, validating the need for such interference rejection. The application of this architecture is verified through a link test analyzing the reception and transmission of modulated data.