Reflectarray Antennas

Printed reflectarrays combine certain advantages of reflector antennas and phased arrays. One major hurdle in the designing of reflectarrays is the compensation of phase difference between various elements. This paper presents reviews of various techniques for phase compensation, like using variable sizes of the patch, adding stubs of variable lengths and use of variable size slots on the ground plane. Further, techniques for circular polarization in space fed arrays are reviewed. They are achieved by rotating the patches at certain angles. Techniques for orthogonal polarization have also been reviewed. Towards the end of the paper recent and future applications for reflectarrays have been reviewed.