The design and characterization of a 60×60element high-gain, wideband transmitarray antenna at 300 GHz are presented. A numerical model is used to accurately design the 8 phase-shifting anisotropic unit-cells of the array (3-bit phase quantization). The planar lens comprises only three metal layers and no metallized vias. It is fabricated using a low-cost, standard printed circuit board technology. A 20-dBi horn is used as a feed. The experimental characterization demonstrates a peak gain of 37.0 dBi with a maximum aperture efficiency of 48.6% and a 1-dB gain bandwidth of 19.0%. These features, combined with the cost-efficient fabrication process, make the prototype a very attractive candidate for point-to-point communications in the 300-GHz band.