Microstrip antenna for RFID device having both far-field and near-field functionality
First Claim
1. A radio frequency transponder comprising:
- an antenna providing electromagnetic coupling for far-field operation, and thereby acting as a far-field antenna;
a ground plane;
a dielectric substrate interposed between the ground plane and the antennaan integrated circuit; and
a matching circuit coupling the antenna with the integrated circuit, the matching circuit including a circuit loop providing inductive coupling for near-field operation, and thereby acting as a near-field antenna.
1 Assignment
0 Petitions
Accused Products
Abstract
Microstrip patch antenna (46), feed structure (48), and matching circuit (50) designs for an RFID tag (10). A balanced feed design using balanced feeds coupled by a shorting stub (56) to create a virtual short between the two feeds so as to eliminate the need for physically connecting the substrate to the ground plane. A dual feed structure design using a four-terminal IC can be connected to two antennas (46a,46b) resonating at different frequencies so as to provide directional and polarization diversity. A combined near-field/far-field design using a microstrip antenna providing electromagnetic coupling for far-field operation, and a looping matching circuit providing inductive coupling for near-field operation. A dual-antenna design using first and second microstrip antennas providing directional diversity when affixed to a cylindrical or conical object, and a protective superstrate (66). An annular antenna (46c) design for application to the top of a metal cylinder around a stem.
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Citations
18 Claims
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1. A radio frequency transponder comprising:
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an antenna providing electromagnetic coupling for far-field operation, and thereby acting as a far-field antenna; a ground plane; a dielectric substrate interposed between the ground plane and the antenna an integrated circuit; and a matching circuit coupling the antenna with the integrated circuit, the matching circuit including a circuit loop providing inductive coupling for near-field operation, and thereby acting as a near-field antenna. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A radio frequency identification transponder comprising:
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a microstrip patch antenna providing electromagnetic coupling for far-field operation, and thereby acting as a far-field antenna; a ground plane; a dielectric substrate interposed between the ground plane and the antenna an integrated circuit; and a matching circuit coupling the microstrip patch antenna with the integrated circuit, the matching circuit including a circuit loop of sufficient size to provide inductive coupling for near-field operation, and thereby acting as a near-field antenna. - View Dependent Claims (14, 15, 16, 17)
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18. A radio frequency identification transponder comprising:
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a microstrip patch antenna providing electromagnetic coupling for far-field operation involving frequencies approximately between ultra-high and microwave frequencies, and thereby acting as a far-field antenna; an integrated circuit; a matching circuit coupling the microstrip patch antenna with the integrated circuit, the matching circuit including a circuit loop of sufficient size to provide inductive coupling for near-field operation involving frequencies approximately between low and high frequencies, and thereby acting as a near-field antenna; a ground plane; and a dielectric substrate interposed between the ground plane and the microstrip patch antenna, the integrated circuit, and the matching circuit.
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Specification