WAVEGUIDE SLOT ANTENNA

A waveguide slot antenna includes a waveguide having a plurality of slots spaced apart by a predefined distance in a central-axis direction of the waveguide, as a radiating section. An uneven section provided on an outer wall surface around the radiating section has a periodic concave-convex pattern extending from the radiating section. The uneven section includes a plurality of protrusions spaced apart by a predefined distance in a dispersed manner in each of an axis direction parallel to the central-axis of the waveguide in which the plurality of slots are arranged and an axis direction orthogonal to the central-axis of the waveguide, and grooves between the protrusions. The plurality of protrusions and the grooves causes incident waves incident from forward in a direction of radiation of radio waves emitted from the radiating section to be reflected in a direction different from an incident direction of the incident waves.