Metasurface leaky-wave antennas: A comparison between slot and patch implementation

This paper is devoted to the analysis and design of a high-gain circularly polarized antenna with low profile for deep space communications in the X-band. In this context, the low-mass and high efficiency requirements can be addressed at the same time by properly designing a layer of patches (slots) printed (etched) on a grounded dielectric substrate. The interaction between this layer and the surface wave launched by a simple and compact feeder leads to leaky-wave radiation. The overall structure is very light and low profile; in particular, for the slot-based solution the dielectric slab is extremely thin (0.15 mm) and characterized by a low permittivity. The design procedure is summarized, and the patch and slot layouts are shown along with their respective directivity patterns