Antenna device and communication apparatus

摘要

An antenna device is configured as a jacket of a communication terminal, such as a mobile terminal, and a communication apparatus includes the antenna device attached to the communication terminal. The antenna device uses an HF-band high frequency signal as a carrier frequency, and is configured as a reader/writer antenna device for a near field communication system. The base body of the antenna device is a plate-shaped base member made of a resin. An antenna coil and a feeding coil are provided integrally with the plate-shaped base member. High-frequency signals are transmitted between the feeding coil and the antenna coil through magnetic coupling in a non-contact manner.

主权项

1. An antenna device comprising:
a plate-shaped base member configured to be attached to a communication terminal or included in the communication terminal; an antenna coil configured with the plate-shaped base member; and a feeding coil that is magnetically coupled to the antenna coil, that is configured with the plate-shaped base member together with the antenna coil, and that is configured to receive and output a feeding signal; wherein the antenna coil includes a first coil conductor having a first winding axis that extends in a direction perpendicular or substantially perpendicular to a principal surface of the plate-shaped base member; the feeding coil is a chip component and includes a second coil conductor having a second winding axis that extends in a direction perpendicular or substantially perpendicular to the first winding axis; the feeding coil further includes a first end face that is perpendicular to the second winding axis and a second end face that is opposed to the first end face; the feeding coil and the antenna coil do not have a single current path; a width of the feeding coil in a direction that is perpendicular to the second winding axis is smaller than a width of the antenna coil in a direction that is parallel or substantially parallel to the principal surface of the plate-shaped base member; a portion of the second coil conductor overlaps with the first coil conductor in the direction perpendicular or substantially perpendicular to the principal surface of the plate-shaped base member; and a minimum distance between the first end face and a center of the antenna coil is shorter than a minimum distance between the second end face and the center of the antenna coil.