Frequency selective surface for directivity enhancement of a terahertz photomixer antenna

An antenna design to increase the directivity of a terahertz (THz) photomixer used as a THz source is presented. The antenna is consisted of a full-wavelength dipole on a GaAs membrane substrate and covered by a frequency-selective surface (FSS). The perfect mirror of ground plane and the partially reflective mirror of FSS form a resonator which produces good transmission characteristics and thus significantly improving the antenna directivity. The cavity in the GaAs membrane substrate has been found to be an important parameter to achieve expected high directivity characteristic when having sufficient large size. We show the antenna geometry, optimization process and the final simulated results of the proposed antenna.