This thesis examines the reflective properties of paraboloid grating reflector antennas. Methods for predicting the antenna radiation characteristics including the Method of Moments (MOM), and array analysis techniques are used. Results of these techniques are then compared with experimentally measured data. The Numerical Electromagnetic Code (NEC) program used in the MOM method is a computer intensive technique, while the array analysis method offers a more analytical approach, valid for the principal plane radiation pattern. The conclusion reached is that the array method offers accurate results with minimum computation required, and is therefore the preferred method in radiation pattern prediction. An empirical graph of reflector efficiency versus the grating interelement gap for the calculation of the reflector gain is presented. Listings of the computer programs developed in the analysis (excluding NEC) are appended.