Antenna device

1. An antenna device comprising:

an antenna;

a first ground conductor; and

an artificial magnetic conductor that is sandwiched between the antenna and the first ground conductor, and separated from the antenna and the first ground conductor,

wherein the first ground conductor includes a first cutaway part on one end side, the first cutaway part having a substantially rectangular shape.

2. The antenna device according to claim 1 , further comprising a via conductor that is disposed separately from a center of a board having a substantially rectangular shape and that causes the antenna, the artificial magnetic conductor, and the first ground conductor to be conducted with each other, the antenna being disposed on the board,

wherein the one end side of the first ground conductor having the first cutaway part is opposite to a side at which the via conductor is disposed with the center of the board being provided between the one end side and the side at which the via conductor is disposed.

3. The antenna device according to claim 1 , further comprising a second ground conductor that is conducted with the first ground conductor,

wherein the artificial magnetic conductor includes a second cutaway part that has a substantially same area as the first cutaway part in the first ground conductor at a position substantially opposing to the first cutaway part in the first ground conductor, and

the second ground conductor is disposed in the second cutaway part and separated from the artificial magnetic conductor.

4. The antenna device according to claim 1 , further comprising a passive conductor that is disposed on the board on which the antenna is disposed.

5. The antenna device according to claim 1 , wherein the first ground conductor and the artificial magnetic conductor are disposed opposedly and substantially overlap each other in a plan view.

6. The antenna device according to claim 2 , wherein the antenna includes a first antenna conductor having a first feedpoint and a second antenna conductor having a second feedpoint, the second antenna conductor being connected to the first ground conductor via the via conductor, the first antenna conductor and the second antenna conductor configuring a dipole antenna.

7. The antenna device according to claim 6 , wherein the artificial magnetic conductor includes a slit at a position where the first antenna conductor and the second antenna conductor that are formed on an upper layer are separated from each other.