Patent attributes
A slot antenna according to the present invention includes: a ground conductor 12 provided on a rear face side of a dielectric substrate 101, the ground conductor having a finite area; a slot 14 which recesses into the ground conductor 12, beginning from an open-end point on a side edge of the ground conductor 12; and a feed line 261 for supplying a high-frequency signal to the slot 14, the feed line 261 intersecting the slot 14. At a first point near the slot, the feed line 261 branches into a group of branch lines including at least two branch lines, such that at least two branch lines in the group of branch lines are connected to each other at a second point near the slot to form at least one loop line 209. A maximum value of a loop length of each loop line 209 is prescribed to be less than 1× effective wavelength at an upper limit frequency of an operating band of the slot antenna. In the group of branch lines, any branch line that does not constitute a part of the loop line 209 but terminates with a leading open-end point has a branch length which is less than a ¼ effective wavelength at the upper limit frequency of the operating band.