An overview of recent advances in retrodirective antenna arrays

An overview of the progress made in the RDA field has been presented. The reflect-type architecture that is perhaps most useful for communication purposes is likely to be the phase-conjugating Pon array; this architecture is capable of handling nonuniform wavefronts though it suffers from a large path loss. To correct the path loss issue associated with reflect type arrays, RDAs based on phase- and power-detection were developed. The power-detecting array offers the advantage that it may be readily miniaturized, as well as adding the benefit of measuring the direction of arrival. Phase-detecting/phase-shifting architectures were found to be ideal if phase detectors were used between adjacent element pairs, as the extra phase information permitted retrodirecting nonuniform wavefronts. The next steps in RDA development involve reducing their size, while optimizing the efficiency of the components that make up their hardware.