AbstractThe design principle and construction of an offset bifocal reflector are discussed and some test results are presented. the reflector surface is designed in a three‐dimensional configuration, and four typical bifocal reflector antennas characterized by the vertical and horizontal cross sections of the subreflector are derived. Mapping of the coordinate system set up on the horn feeder is accomplished with a geometrical optics technique, and it is found that an antenna with low distortion cross‐polarization degradation attributable to asymmetry is possible.A 1.3 m bifocal reflector antenna at 14/11 GHz with a beam separation of 9° was designed and fabricated, and its radiation properties were measured with offset feeding, which is useful in constructing a multibeam antenna. the radiation properties within this beam separation angle are equivalent to those of a single pencil‐beam antenna such as the Cassegrainian; the cross‐polarization level is less than ‐30 dB in the