Radio frequency identification tag
First Claim
1. A far-field radio frequency identification (RFID) tag responsive to a plurality of continuous wave (CW) unmodulated reception signals selected from frequencies comprising a predetermined frequency band, the RFID tag comprising:
- a reception antenna circuit for receiving the reception signals;
a signal processor for determining whether the reception signals correspond to a plurality of tag identification frequencies as a correlation, and producing responsive signals in response to the correlation;
an oscillator for supplying a carrier signal at a carrier frequency; and
a transmission antenna circuit for combining the carrier signal with the response signals to produce transmit signals, and dispatching the transmit signals.
1 Assignment
0 Petitions
Accused Products
Abstract
Radio frequency identification (RFID) includes far-field systems associated with an RFID interrogator and an RFID tag. The RFID interrogator produces continuous wave (CW) unmodulated signals selected from frequencies comprising a predetermined frequency band. The RFID tag includes reception and transmission antenna circuits, a signal processor, and an oscillator. The reception antenna circuit receives the reception signals from the RFID interrogator. The signal processor determines whether the reception signals correspond to a plurality of tag identification frequencies as a correlation. The signal processor also produces responsive signals in response to the correlation. The oscillator supplies a carrier frequency. The transmission antenna circuit combines the carrier signal with the response signals to produce transmit signals, and then dispatches the transmit signals.
-
Citations
19 Claims
-
1. A far-field radio frequency identification (RFID) tag responsive to a plurality of continuous wave (CW) unmodulated reception signals selected from frequencies comprising a predetermined frequency band, the RFID tag comprising:
-
a reception antenna circuit for receiving the reception signals; a signal processor for determining whether the reception signals correspond to a plurality of tag identification frequencies as a correlation, and producing responsive signals in response to the correlation; an oscillator for supplying a carrier signal at a carrier frequency; and a transmission antenna circuit for combining the carrier signal with the response signals to produce transmit signals, and dispatching the transmit signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A far-field radio frequency identification (RFID) tag responsive to a plurality of continuous wave (CW) unmodulated reception signals selected from frequencies comprising a predetermined frequency band, the RFID tag comprising:
-
a reception antenna circuit for receiving the CW reception signals; an analog-to-digital converter (ADC) for converting the CW reception signals to digital reception signals; a digital signal processor (DSP) for determining whether the reception signals correspond to a plurality of tag identification frequencies as a correlation, and producing digital responsive signals in response to the correlation; a digital-to-analog converter (DAC) for converting the digital responsive signals to analog responsive signals; an oscillator circuit for supplying a carrier signal at a carrier frequency; and a transmission antenna circuit for combining the carrier signal with the analog responsive signals to produce transmit signals, and dispatching the transmit signals. - View Dependent Claims (10, 11, 12, 13, 14, 15)
-
-
16. A method for responding to a plurality of continuous wave (CW) unmodulated reception signals by a far-field radio frequency identification (RFID) tag, the reception signals being selected from frequencies within a predetermined frequency band, the method comprising:
-
receiving the reception signals by a reception antenna circuit; determining whether the reception signals correspond to a plurality of tag identification frequencies as a correlation by a signal processor; producing responsive signals by the signal processor in response to the correlation; supplying to the responsive signals by an oscillator a carrier signal at a carrier frequency; combining the carrier signal with the response signals by a transmission antenna circuit to produce transmit signals; and dispatching the transmit signals by the transmission antenna circuit. - View Dependent Claims (17, 18, 19)
-
Specification