Piezo-based circuit for modifying functionality of RFID tags
A radio frequency identification (RFID) tag comprising a tag integrated circuit (IC), an antenna coupled to the tag IC, and an impedance tuned circuit coupled to the antenna, wherein the impedance tuned circuit configured to tune a circuit impedance of the antenna based on power received by the impedance tuned circuit. The RFID tag further comprises a piezo electric energy harvesting module coupled to the impedance tuned circuit, wherein the piezo electric energy harvesting module is configured to supply the power to the impedance tuned circuit.
1 . A radio frequency identification (RFID) tag comprising:
a tag integrated circuit (IC), wherein the tag IC comprises a functional impedance;
an antenna coupled to the tag IC;
an impedance tuned circuit coupled to the antenna via a latching switch; and
a piezo electric energy harvesting module coupled to the impedance tuned circuit via the latching switch, wherein the piezo electric energy harvesting module actuates the latching switch based on a movement of the RFID tag to electrically connect the impedance tuned circuit to the antenna, wherein in an instance in which the impedance tuned circuit is electrically coupled to the antenna, the impedance of a combination of the impedance tuned circuit and the antenna matches the impedance of the tag IC such that radio frequency (RF) signals are transmitted and received via the antenna.
2 . The RFID tag of claim 1 , wherein the impedance tuned circuit is further configured to control operation of the antenna and the tag IC by tuning the circuit impedance of the antenna.
3 . The RFID tag of claim 1 , further comprising the latching switch coupled from the piezo electric energy harvesting module to the impedance tuned circuit.
4 . The RFID tag of claim 1 , wherein the piezo electric energy harvesting module comprises a piezoelectric transducer, a power management module, and an energy storage unit.
5 . The RFID tag of claim 1 , wherein the impedance tuned circuit is further configured to: (i) tune a first circuit impedance for the antenna based on no power is received from the piezo electric energy harvesting module, and (ii) tune a second circuit impedance for the antenna based on power is received from the piezo electric energy harvesting module.
6 . The RFID tag of claim 5 , wherein the first circuit impedance for the antenna prevents the antenna from receiving and transmitting the RF signals and the second circuit impedance for the antenna allows the antenna to receive and transmit the RF signals.
7 . The RFID tag of claim 6 , wherein a non-functional circuit impedance is greater than a functional circuit impedance of the tag IC.
8 . The RFID tag of claim 1 , wherein the piezo electric energy harvesting module is further configured to supply the power to the impedance tuned circuit based on the movement of the RFID tag.
9 . The RFID tag of claim 1 , wherein the piezo electric energy harvesting module is further configured to stop supplying the power to the impedance tuned circuit based on non-movement of the RFID tag.
10 . A radio frequency identification (RFID) tag comprising:
an antenna configured to receive and transmit radio frequency (RF) signals;
a tag integrated circuit (IC) coupled to the antenna, the tag IC comprising an input/output (I/O) port, and the tag IC is configured to generate discrete signals for transmission in the RF signals based on electric signals received on the I/O port; and
a piezo electric energy harvesting module coupled to the I/O port of the tag IC via a latching switch, wherein the piezo electric energy harvesting module actuates the latching switch based on a movement of the RFID tag to generate the electric signals to the I/O port of the tag IC such that the RF signals are transmitted and received via the antenna.
11 . The RFID tag of claim 10 , wherein the tag IC is further configured to generate the discrete signals based on the movement of the RFID tag.
12 . The RFID tag of claim 11 , wherein the tag IC is further configured to generate a high discrete signal based on the RFID tag being in motion.
13 . The RFID tag of claim 11 , wherein the tag IC is further configured to generate a low discrete signal based on the RFID tag being stationary.