The radiation pattern of a corner reflector fed by a circular conducting cylinder with an axial slot is examined. An integral equation for the TE case is derived using Green's second identity. The method of moments is then employed to obtain a numerical solution for the integral equation. In order to study the effect of the slotted cylinder feed, radiation patterns corresponding to a line source feed are also calculated. The comparison between radiation patterns of corner reflector antenna fed by a line source and their correspondence with a slotted circular cylinder feed showed that the later can give a narrower beam width, which increases the antenna gain.