Patent ID: 9716317
Date: 2017-07-25
CPC Classifications: H01Q

Claim:
1. An antenna device comprising: a rectangular plate-like soft magnetic body provided with a loop-like coil, wherein: the coil is formed of a conductive pattern and formed on an insulation sheet; the coil is disposed from a front surface to a rear surface of the soft magnetic body so that a section surrounded by the coil on the insulation sheet overlaps with, at least in part, a first edge of the soft magnetic body which is one of four edges of the soft magnetic body, and does not overlap with an opposite edge of the soft magnetic body that is opposite to the first edge; the coil of the conductive pattern is configured so that an area, which is in the front surface of the soft magnetic body and included in the section surrounded by the coil on the insulation sheet, is larger than another area, which is in the rear surface of the soft magnetic body and included in the section surrounded by the coil on the insulation sheet; the coil reaches a region close to the opposite edge over the front surface of the soft magnetic body such that the coil has wide directivity between a direction perpendicular to the front surface of the soft magnetic body and another direction perpendicular to the first edge; the insulation sheet has a front part located on the front surface of the soft magnetic body, a rear part located on the rear surface of the soft magnetic body, and a middle part located on the first edge of the soft magnetic body; the front part of the insulation sheet located on the front surface of the soft magnetic body has a same size as the rear part of the insulation sheet located on the rear surface of the soft magnetic body, and the middle part of the insulation sheet located on the first edge of the soft magnetic body is arranged between the front part and the rear part; when the insulation sheet is expanded into a planar plane together with the coil so as to extend along a predetermined direction, the middle part is located at a middle of the insulation sheet in the predetermined direction between the front part and the rear part, a majority portion of the coil is located on the front part of the insulation sheet in the predetermined direction and only a rear end portion of the coil having a length in the predetermined direction that is smaller than a length of the majority portion of the coil in the predetermined direction is located on the rear part of the insulation sheet; and the insulation sheet is folded around the magnetic body such that the middle part is located on the first edge of the soft magnetic body, and such that the rear end portion of the coil is located on the rear surface of the soft magnetic body at a position closer to the first edge than to the opposite edge; and the coil is entirely arranged on the front surface, the rear surface and at least one of the four edges of the soft magnetic body, including the first edge, via the insulation sheet.