Antenna device

An antenna device comprising:

• a finite ground plane;
• a rectangular conductor plate provided above the finite ground plane, whose one side is connected to the finite ground plane, and having a bent portion substantially parallel with the one side;
• an antenna disposed substantially parallel with the finite ground plane above the finite ground plane, extending in a direction substantially perpendicular to the one side, and having a feeding point positioned near the other side facing the one side of the rectangular conductor plate;
• and
• a magnetic material provided in at least a part of space between the finite ground plane and the antenna,
• wherein the magnetic material comprises,
• core-shell magnetic particles including a metal core containing a magnetic metal containing at least one element selected from the group of Fe, Co, and Ni, at least one nonmagnetic metal selected from the group of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, a rare-earth element, Ba, and Sr, and at least one element selected from carbon (C) and nitrogen (N) which is dissolved into the magnetic metal, and an oxide coating layer coated on the surface of the metal core and made of an oxide containing at least one nonmagnetic metal as one of the components of the metal core, the oxide containing at least one element selected from the group of Fe, Co, and Ni which is contained in the metal core;
• and
• an insulating material of a resin or an inorganic material having gaps and in which the core-shell magnetic particles are dispersed.