RIFID TAGS AND METHODS OF DESIGNING RFID TAGS
First Claim
1. A radio frequency identification (RFID) tag comprising:
- a tag antenna;
a matching circuit coupled to the tag antenna;
a shorting device coupled to the tag antenna and the matching circuit, wherein conductivity of the shorting device affects a reflection coefficient of the tag antenna; and
a tag circuit coupled to the matching circuit and the shorting device, the tag circuit configured to control the shorting device;
wherein a difference between a reflection coefficient of the tag antenna when the shorting device is conductive and a reflection coefficient of the tag antenna when the shorting device is non-conductive is greater than or equal to approximately 0.8.
4 Assignments
0 Petitions
Accused Products
Abstract
RFID tags and methods of designing RFID tags. At least some of the illustrative embodiments are RFID tags comprising a tag antenna, a matching circuit coupled to the tag antenna, a shorting device coupled to the tag antenna and the matching circuit (wherein the shorting device is configured to selectively couple the tag antenna to common), and a tag circuit coupled to the matching circuit and the shorting device (the tag circuit configured to control the shorting device). In one or more such embodiments, a difference between a reflection coefficient of the tag antenna when the shorting device is conductive and a reflection coefficient of the tag antenna when shorting device is non-conductive is greater than or equal to approximately 0.8.
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Citations
21 Claims
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1. A radio frequency identification (RFID) tag comprising:
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a tag antenna; a matching circuit coupled to the tag antenna; a shorting device coupled to the tag antenna and the matching circuit, wherein conductivity of the shorting device affects a reflection coefficient of the tag antenna; and a tag circuit coupled to the matching circuit and the shorting device, the tag circuit configured to control the shorting device; wherein a difference between a reflection coefficient of the tag antenna when the shorting device is conductive and a reflection coefficient of the tag antenna when the shorting device is non-conductive is greater than or equal to approximately 0.8. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A radio frequency identification (RFID) tag comprising:
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a tag antenna; a matching circuit coupled to the tag antenna; a tag circuit coupled to the tag antenna through the matching circuit; and a switch configured to selectively couple the tag antenna to a common potential; wherein an impedance of the antenna is more than approximately four (4) times a conducting impedance of the switch. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method comprising:
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designing an antenna for a radio frequency transceiver, wherein physical characteristics of the antenna are selected independent of effects of the physical characteristic on impedance of the antenna; and
thendesigning an impedance matching circuit having approximately the same impedance as the antenna; and selecting a shorting device with a conductive impedance, the shorting device selected based on the impedance of the antenna. - View Dependent Claims (18, 19, 20, 21)
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Specification