Reconfigurability Mechanisms With Scanning Rate Control for Omega-Bianisotropic Huygens' Metasurface Leaky-Wave Antennas

In this paper, different reconfigurability mechanisms are proposed to scan the pointing direction at a fixed frequency of recently-proposed leaky-wave antennas based on omega-bianisotropic Huygens' metasurfaces. The tunability of both the waveguide height and the dielectric permittivity of the substrate filling the waveguide are studied, extracting theoretical expressions to predict the dependence of the beam pointing direction with the design parameters. It is shown that it is possible to control the scanning rate, a challenging task for conventional leaky-wave antennas, leading to different performances: high scanning, radiation pattern stability and backward-to-forward scanning. Additionally, the control of the scanning rate is exploited to reduce the beam squinting when varying the frequency. Simulation results of several designs with both impedance sheets and physical realization to implement the metasurfaces demonstrate the validity of the theoretical predictions and the reconfigurability potential of such a structure.