Controlled reduction of read range of UHF RFID tag
AssigneeNeology, Inc.
InventorTareef Al-Mahdawi
Life of this patent
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Abstract
An RFID tag antenna system comprises a tag antenna with complex impedance and an integrated circuit (IC) with input impedance. A controlled mismatch between the tag antenna and IC impedances reduces the realized gain of the tag antenna to a desired level. The system calculates a reflection coefficient to reduce antenna gain by a predetermined amount. A program converts the reflection coefficient to realized gain and calculates theoretical read distance based on realized gain and IC sensitivity. The process generates a read distance profile over frequency. This approach enables precise control of RFID tag performance, allowing customization for specific applications while maintaining optimal functionality.
Claims16
An RFID tag antenna system comprising:
- a tag antenna having a complex impedance based on a design of the tag antenna;
- an integrated circuit (IC) having an complex input impedance;
- and
- wherein there is a controlled mismatch between the tag antenna complex impedance and the IC complex input impedance due to the design, wherein the controlled mismatch reduces a realized gain of the tag antenna to control the output of the RFID tag antenna system such that the read range is reduce to achieve optimum performance in a multi-tag environment, wherein the controlled mismatch is achieved by designing the tag antenna to have a reflection coefficient that reduces the realized antenna gain by a predetermined amount.
A method for designing an RFID tag antenna system, the method comprising:
- determining a complex impedance of a tag antenna having an antenna design;
- determining an complex input impedance of an integrated circuit (IC);
- introducing a controlled mismatch between the tag antenna complex impedance and the IC complex input impedance via changes in the antenna design that reduces a realized gain of the tag antenna to a desired level based on the controlled mismatch to control the output of the RFID tag antenna system such that the read range is reduce to achieve optimum performance in a multi-tag environment, wherein introducing the controlled mismatch comprises designing the tag antenna to have a reflection coefficient that reduces the realized antenna gain by a predetermined amount, without introducing additional components.
A computer-implemented method for optimizing RFID tag antenna performance, the method comprising:
- receiving input parameters including a tag antenna complex impedance and an IC input impedance;
- calculating a reflection coefficient based on the tag antenna complex impedance and the IC input impedance;
- determining a realized gain of the tag antenna based on the reflection coefficient;
- calculating a theoretical read distance based on the realized gain and IC sensitivity;
- generating a read distance profile over a frequency range;
- and
- adjusting the tag antenna complex impedance to achieve a desired realized gain that is reduced relative to a maximum realized gain to control the output of the RFID tag antenna system such that the read range is reduce to achieve optimum performance in a multi-tag environment.
Dependencies are inferred from the claim text.