Patent ID: 7719472
Filing Date: 2010-05-18
Classification: H01Q

Abstract:
1. An antenna unit capable of being attached to a detected body that includes a conductive member and resign layers sandwiching the conductive member, the antenna unit comprising: a non-conductive base film that includes a first surface and a second surface facing an opposite side to the first surface and that is attached to the resign layer of the detected body at the second surface; an endless conductive flat plate member attached onto the first surface of the base film and having an opening in a center thereof; a dipole antenna attached to the first surface of the base film so as to be positioned in the opening of the conductive flat plate member in a state of being isolated from the conductive flat plate member by having a gap formed between the dipole antenna and an inner circumferential edge of the conductive flat plate member; and an IC tip attached onto the dipole antenna, wherein the antenna unit is capable of being attached to the detected body so that, as viewed in a direction orthogonal to the conductive flat plate member, the conductive member of the detected body is not positioned in the opening in the center of the conductive flat plate member and is overlapped with the conductive flat plate member, and wherein the dipole antenna and the conductive flat plate member have resonance frequencies that are different from each other.