Improving Performance of Metasurfaces-based Beam-Steering 2D-Leaky Wave Resonant-Cavity Antennas

This paper presents a design strategy to improve the radiation performance of the metasurface-based beam-steering resonant-cavity antenna (RCA). The antenna system uses phasegradient metasurfaces (PGMs) placed within the RCA’s near-field. The concept is referred to as near-field meta-steering, an efficient beam-steering solution yielding low-profile and planar antenna systems for on-the-move connectivity applications. The PGMs of these antennas have arrays of cells, designed using infinite periodic boundary conditions and plane-wave propagation. While in PGMs, the periodicity does not exist one of the lateral directions. Placing these surfaces in the near-field region of the RCA, deteriorates the antenna system’s performance, including gain in the desired direction and shift in the operating frequency. It has been observed that the spacing of the PGMs should be set to 0.25 from the RCA while the spacing between PGMs itself should be less than 0.25 to have the highest gain at the operating frequency.