Metasurface-Enabled Cavity Antenna : Beam Steering with Dramatically Reduced Fed Elements

We present a metasurface-enabled cavity antenna that achieves full beam steering but features a significantly reduced number of fed elements. To create this antenna, we first excite a traveling wave in a cavity enclosed by an active metasurface, then form the desired radiation by leaking the cavity wave through a perforated top plate. We hence achieve a steerable antenna for which the number of fed elements scales with the perimeter and not the area of the radiation aperture. In this letter, we report two models of this cavity antenna whose beamwidths and sidelobe levels closely resemble a traditional microstrip patch array of the same aperture size. Hence, dramatic savings in feed cost and complexity are achieved without compromising the antenna gain, the beam shape, or steerability. The proposed antennas shall attract strong interest in highly directive millimeter-wave beamforming applications.