Near-field measurement and far-field characterization of a high-gain Cassegrain antenna at 300 GHz band base on a photonics technology

Near-field antenna pattern of a Cassegrain antenna at 300 GHz was measured based on non-polarimetric electrooptic (EO) frequency down conversion technique combined with a self-heterodyne system. Measured near-field pattern of the antenna, whose diameter and designed antenna gain are 152 mm and 48 dBi, respectively, was converted to the farfield pattern to characterize the radiation pattern of the antenna. The full width at a half maximum of the antenna is obtained 0.46 deg. and 0.40 deg. for E-plane and Hplane, respectively.