Reflectarrays and Metasurface Antennas at Millimeter and Terahertz Waves

In this paper we present an overview of different metasurface antenna technologies that are being developed in our laboratory at millimeter and terahertz waves for space applications. We will show that even though transmit- and reflect-arrays have made tremendous progress at millimeter-wave frequencies in recent years, it is challenging to use them at terahertz frequencies. Moreover, for space applications, metasurface antennas at these frequencies are sometimes preferable as they require less volume. We provide detailed scientific motivations for some of the metasurface antennas working in the Ku-band to W-band and beyond. We report all-metal metasurface antennas with high efficiency working in the Ka-band and beam-steering metasurface antennas working in W-band for radar and spectrometer applications.