US Patent 10090600 Waveguide device, and antenna device including the waveguide device

A waveguide device according to an embodiment includes an electrically conductive member having an electrically conductive surface, a waveguide member extending so as to face along the electrically conductive surface, and stretches of artificial magnetic conductor on both sides of the waveguide member. The waveguide member includes a first portion extending in one direction, and at least two branches extending in mutually different directions from one end of the first portion, the at least two branches including a second portion and a third portion. The second portion has a recess in a side face that connects to one side face of the first portion, the recess reaching the waveguide face.