In this paper, a W-band reflector antenna is proposed for foreign object debris (FOD) detection. The antenna is designed following the principle of reflector antenna, where the cutting paraboloid is used as the reflector., and the pyramidal horn is used as the source. The antenna is fed in an offset manner to obtain high gain and the desired fan beam. The main advantage of the antenna is its simple structure, low cost and better compressive strength compared with other FOD antennas. The measurement is in consistent with the full-wave simulation results, verifying the feasibility of the proposed design.