Low-profile single-feed highly-directive antennas based on cavity-excited metasurfaces

We propose a novel antenna design combining the simplicity of shielded Fabry-Perot leaky-wave antennas (FP-LWA) with the performance of antenna arrays. The device is based on a probe-fed shielded FP-LWA structure, with the standard partially-reflecting surface replaced by a metasurface. The cavity excitation is optimized to uniformly illuminate the aperture, forming radiating hot spots half-a-wavelength apart, while the metasurface imposes the linear phase required to promote directive radiation. This yields a probe-fed low-profile antenna with near-unity aperture illumination efficiency and no edge-taper losses. In previous work we have shown that a Huygens' metasurface can be used to that end; in this report we present an improved design featuring an omega-type bian-isotropic metasurface. The compact device structure (with respect to lens or reflector antennas) and the simple and efficient feeding scheme (with respect to antenna arrays) make these cavity-excited metasurface antennas very appealing for industrial applications, such as satellite communication or automotive radars.