Achievement of beam steering in terahertz band based on frequency-scanning grating-reflector antenna

A frequency-scanning grating-reflector antenna operating in the 0.2 THz band is proposed. The antenna system consists of a planar grating reflector, a thin lens and a feed horn placed at the focal point of the lens. The beam-scanning property based on the frequency sweeping was analysed and optimised based on Floquet´s theorem. A bilayer structure is introduced to improve the diffraction efficiency and to suppress the specular beam. The frequency-controlled beam steering concept was verified by the quasi-optical measurements in the 0.2 THz band. The measured scanning range is 13.55° over the frequency band 180-220 GHz. The specular beams are remarkably inhibited with the diffractive efficiency as high as over 89%. The presented antenna has the advantage of the convenience to be extended to a higher frequency with a high directivity.