RADIATION-PATTERNS FROM LENS-COUPLED TERAHERTZ ANTENNAS

We report on investigations of the angular distribution of the radiati on emitted from a terahertz antenna system equipped with a truncated s pherical silicon lens. The pattern is calculated by wide-angle interfe rence principles and Huygens-Fresnel diffraction theory. Experimental determination of the radiation pattern is performed by spatially resol ved terahertz time-domain spectroscopy. Good agreement between theory and experiment is obtained, and we find that the terahertz beam can be represented by a Gaussian beam emitted from a circular aperture equal to the diameter of the lens.