A reflectarray utilizes key features of reflector antennas and phased array antennas by allowing a feed to illuminate its planar main reflector's array elements to produce a collimating beam. Consequently, this mechanism eliminates the feed-network as required in phased-array antennas. Maximizing the reflectarray antenna gain requires a phase correcting mechanism to be applied to its individual array elements. Phase correction can be achieved in a number of ways by maintaining phase uniformity across the reflectarray surface. Independent of the type of phase compensation scheme, in this study, we attempt to extend analytical techniques in reflector analysis to reflectarray antennas by introducing a number of approaches to estimate the reflectarray antenna performances.