Antenna stack

An antenna stack, comprising,

• a cover having an outer face, an inside face opposite the outer face, and a body therebetween, the cover additionally having a cavity formed therein extending into the body from the inside face, wherein the body is of a first material, wherein the first material has a dielectric constant at 25° C. at 79 GHz;
• an antenna patch positioned within the cavity;
• and
• a waveguide layer underlying the cover and bonded thereto, wherein major surfaces of the waveguide layer are overlaid with an electrical conductor that includes openings in the conductor that open to feed channels extending through the waveguide layer, wherein the waveguide layer is of a second material, wherein the second material is inorganic, wherein the second material has a dielectric constant at 79 GHz at 25° C. that is at least twice the dielectric constant of the first material;
• wherein the antenna patch is physically spaced apart from the waveguide layer by a distance of at least 10 micrometers and less than 1.4 millimeters.