Millimeter-Wave Holographic Metasurface Leaky-Wave Multi-Beam Antennas with Gain and Polarization Control

This paper introduces a holographic multiple-beam leaky-wave antenna (LWA) synthesized by metasurfaces with controllable polarization and amplitude of the radiated beams. The interference pattern is first obtained by the inner product of the reference and object wave vector field functions, the former being that of a cylindrical source surface wave, the latter comprising the vector sum of the phase projections onto the hologram of the various incident plane waves, the directions, amplitudes and polarizations of which are to be reproduced as LWA beams upon illumination of the synthesized hologram by the same source. By DC-biasing and amplitude modulating the sinusoidal interference pattern to fit the surface reactance range of the metasurface patch arrays for the synthesis, the spatial distribution of the required surface impedance over the holographic surface is then devised. Simulations of designs by this approach check well with expected results in terms of the beam direction, amplitude, and polarizations.