Antenna for radio frequency identification
AssigneeHitachi, Ltd.
InventorMitsuo Usami
Life of this patent
Estimating the term…
Abstract
To provide an antenna shape devised to be integrated and compact. The antenna connected to an IC chip that performs wireless identification includes a slit that separates two connection points with respect to the IC chip, in which a length of the slit is approximately 3 millimeters, and a width of the slit is in a range of from 0.8 millimeter to 1.4 millimeters.
Claims18
A non-resonant antenna designated to operate at substantially 2.45 GHz and to be connected to an IC chip for wireless identification, comprising:
- a conductor having an opening, the opening extending substantially 3 mm long in a first direction and 0.8-1.4 mm wide in a second direction, wherein the first direction and the second direction cross at a right angle, said opening including a contiguous gap extending from the opening through the conductor;
- and
- a first connection point for a first input terminal of the IC chip located on a first side of said gap and a second connection point for a second input terminal of the IC chip located on a second side of said gap,
- wherein the opening constitutes a distributed constant circuit, and
- wherein an impedance of the distributed constant circuit matches an input impedance of the IC chip.
A non-resonant antenna designated to operate at substantially 2.45 GHz and to be connected to an IC chip for wireless identification, comprising:
- a conductor making up said antenna, said conductor having an opening extending 2.4-3.0 mm long in a first direction, and extending 0.8-1.4 mm wide in a second direction, wherein said first direction and said second direction cross at a right angle to achieve an opening area of 3.0-4.2 square mm, said opening including a contiguous gap extending from the opening through the conductor;
- and
- a first connection point for a first input terminal of the IC chip located on a first side of said gap and a second connection point for a second input terminal of the IC chip located on a second side of said gap,
- wherein the opening constitutes a distributed constant circuit, and
- wherein an impedance of the distributed constant circuit matches an input impedance of the IC chip.
A non-resonant antenna designed to operate at substantially 2.45 GHz band and to be connected to an IC chip for wireless identification, comprising:
- a conductor having a long narrow opening that extends 2.4-3.0 mm long in a first direction and 0.8-1.4 mm wide in a second direction, wherein first direction and the second direction cross at a right angle to achieve an opening area of 3.0-4.2 square millimeters, said opening including a contiguous gap extending from the opening through the conductor so that said opening is not closed on one side;
- and
- a first connection point for a first input terminal of the IC chip located on a first side of said gap and a second connection point for a second input terminal of the IC chip located on a second side of said gap,
- wherein an inductance exists the along an opening length of the first direction;
- wherein a capacitance exists inversely proportional to an opening width of the second direction;
- wherein an impedance of the distributed constant circuit comprising the inductance and the capacitance matches an input impedance of the IC chip;
- and
- wherein a current mainly flows in a vicinity of a center portion of the non-resonant antenna and does not flow in corner portions of the non-resonant antenna.
Dependencies are inferred from the claim text.