Passive Metasurface Based Cavity Antenna for WideAngle Beam Steering

In this paper, we present a multi-probe cavity antenna for the wide-angle beam steering, which is based on a single passive metasurface. The semi-analytical formulation modeling the field distribution of the cavity antenna is developed, depending on which, we build the gradient-based optimization algorithm to determine the reflection $r(x)$ and transmission $t(x)$ coefficients distribution of the metasurface which allows us to realize the beam steerability of the cavity antenna. As a proof of concept, we have designed a three-probe cavity antenna that operates at 10 GHz, yielding three switchable directive beams at $-45^{\circ}, 0^{\circ},+45^{\circ}$ with regard to the broadside.