Radio frequency identification (RFID) with sensors

1 . An integrated circuit for a radio frequency identification (RFID) tag, the integrated circuit comprises:

an antenna port operable for coupling to an external antenna wherein the antenna includes one or more radiating elements for electromagnetically transmitting outbound radio frequency (RF) electromagnetic signals and for electromagnetically receiving inbound RF electromagnetic signals;

a power harvesting circuit operably coupled to the antenna port, wherein the power harvesting circuit is operable to generate an AC current from the inbound RF electromagnetic signals when the inbound RF electromagnetic signals are received via the antenna port;

a regulator operably coupled to convert the AC current into a DC operating power;

a shunt circuit coupled to shunt current of a DC voltage of the DC operating power based on a shunt threshold;

an external element port operably coupled to an external sensor that senses an external condition;

a sensing engine operably coupled to the external element port and to the regulator, wherein, when operational, the sensing engine:

generates a signal representative of a sensed external condition that is sensed by the external sensor;

generates a digital value of the signal;

generates an outbound signal that includes the digital value; and

a radio frequency (RF) transmitter is operably coupled to the antenna port and to the regulator, wherein, when operational, the RF transmitter is further operably coupled to:

transmit, based on the outbound signal and via the external antenna, an outbound RF signal to an RFID reader.

2 . The integrated circuit of claim 1 , wherein the sensing engine comprises:

a reference block operably coupled to the external element port, wherein, when operational, the reference block:

generates the signal representative of the sensed external condition that is sensed by the external sensor; and

generates the digital value of the signal;

memory operably coupled to store the digital value;

a processing unit operably coupled to the memory and to the reference block, wherein the processing unit is operably coupled to:

generate the outbound signal that includes the digital value.

3 . The integrated circuit of claim 2 , wherein the reference block comprises:

an auto gain control (AGC) circuit coupled to first and second terminals of the external port;

an analog to digital converter operably coupled to the AGC circuit, wherein the AGC circuit adjusts amplitude of an analog sensed signal received via the external port and the analog to digital converter converts the analog sensed signal into the digital value.

4 . The integrated circuit of claim 1 further comprises:

the sensing engine is operably coupled to generate the signal to be representative of one or more of:

a sensed temperature that is sensed by the external sensor;

a sensed moisture level that is sensed by the external sensor;

a sensed pressure that is sensed by the external sensor;

a sensed humidity that is sensed by the external sensor;

a sensed light that is sensed by the external sensor; and

a sensed gas level that is sensed by the external sensor.

5 . The integrated circuit of claim 1 , wherein the sensing engine further comprises:

a second reference block operably coupled to a second external element port, wherein, when operational, the second reference block

generates a second signal representative of a second sensed external condition that is sensed by a second external sensor that is operably coupled to the second external element port; and

generates a second digital value;

wherein the memory is further operably coupled to store the second digital value;

wherein the processing unit is further operably coupled to generate a second outbound signal that includes the second digital value or updates the outbound signal to include the second digital value;

wherein the RF transmitter is further operably coupled to transmit, via the external antenna, the second outbound signal within the outbound RF signal or within a second outbound RF signal to an RFID reader.

6 . The integrated circuit of claim 1 further comprises:

the RF transmitter is further operable to transmit the outbound RF signal to the RFID reader upon power up of the integrated circuit or in response to a request from the RFID reader.

7 . The integrated circuit of claim 1 further comprises:

an on-chip sensor operably coupled to the sensing engine;

wherein the sensing engine is further operably coupled to:

generates a second signal representative of a sensed condition by the on-chip sensor; and

generates a second digital value of the second signal.

8 . The integrated circuit of claim 7 further comprises:

the sensing engine is further operably coupled to generate a second outbound signal that includes the second digital value; and

wherein the RF transmitter is further operably coupled to:

convert the second outbound signal into a second outbound RF signal; and

transmit, via the external antenna, the second outbound RF signal to an RFID reader.

9 . The integrated circuit of claim 7 further comprises:

the sensing engine is further operably coupled to generate the outbound signal to further include the second digital value.

10 . The integrated circuit of claim 7 further comprises:

calibrating the on-chip sensor at a wafer level or at a die level prior to deployment in the RFID tag to produce calibration data; and

storing the calibration data in memory of the sensing engine.

11 . The integrated circuit of claim 7 further comprises:

calibrating the on-chip sensor based on the sensed external condition and the digital value of the signal.

12 . The integrated circuit of claim 1 further comprises:

the sensing engine calibrating the generation of the signal representative of the sensed external condition that is sensed by the external sensor based on a table of calibration data.

13 . The integrated circuit of claim 12 further comprises:

an RF receiver to receive an inbound RF signal from the RFID reader, wherein the inbound signal includes at least one calibration data point of the calibration data in the table.

14 . The integrated circuit of claim 13 further comprises:

the sensing engine storing the table of calibration data in memory of the sensing engine.

15 . A radio frequency identification (RFID) tag comprises:

a substrate;

an external antenna mounted on the substrate, wherein the external antenna includes one or more radiating elements for electromagnetically transmitting outbound radio frequency (RF) electromagnetic signals and for electromagnetically receiving inbound RF electromagnetic signals;

an external sensor mounted on the substrate, wherein, when operable, the external sensor senses an external condition; and

an integrated circuit mounted on the substrate, wherein the integrated circuit includes:

an antenna port operable for coupling to the external antenna;

a power harvesting circuit operably coupled to the antenna port, wherein the power harvesting circuit is operable to generate an AC current from the inbound RF electromagnetic signals when the inbound RF electromagnetic signals are received via the antenna port;

a regulator operably coupled to convert the AC current into a DC operating power;

a shunt circuit coupled to shunt current of a DC voltage of the DC operating power based on a shunt threshold;

an external element port operably coupled to the external sensor;

a sensing engine operably coupled to the external element port and to the regulator, wherein, when operational, the sensing engine:

generates a signal representative of a sensed external condition that is sensed by the external sensor;

generates a digital value of the signal;

generate an outbound signal that includes the digital value; and

a radio frequency (RF) transmitter is operably coupled to the antenna port and to the regulator, wherein, when operational, the RF transmitter is further operably coupled to:

transmit, based on the outbound signal and via the external antenna, an outbound RF signal to an RFID reader.

16 . An integrated circuit for a radio frequency identification (RFID) tag, the integrated circuit comprises:

an antenna port operable for coupling to an external antenna, wherein the antenna includes one or more radiating elements for electromagnetically transmitting outbound radio frequency (RF) electromagnetic signals and for electromagnetically receiving inbound RF electromagnetic signals;

a power harvesting circuit operably coupled to the antenna port, wherein the power harvesting circuit is operable to generate an AC current from the inbound RF electromagnetic signals when the inbound RF electromagnetic signals are received via the antenna port;

a regulator operably coupled to convert the AC current into a DC operating power;

a shunt circuit coupled to shunt current of a DC voltage of the DC operating power based on a shunt threshold;

an on-chip sensor operable to sense a condition;

a sensing engine operably coupled to the on-chip sensor and to the regulator, wherein, when operational, the sensing engine:

generates a signal representative of a sensed condition that is sensed by the on-chip sensor;

generates a digital value of the signal;

generate an outbound signal that includes the digital value; and

a radio frequency (RF) transmitter is operably coupled to the antenna port and to the regulator, wherein, when operational, the RF transmitter is further operably coupled to:

transmit, based on the outbound signal and via the external antenna, an outbound RF signal to an RFID reader.

17 . The integrated circuit of claim 16 further comprises:

the sensing engine is operably coupled to generate the signal to be representative of one or more of:

a sensed temperature that is sensed by the on-chip sensor;

a sensed moisture level that is sensed by the on-chip sensor;

a sensed pressure that is sensed by the on-chip sensor;

a sensed humidity that is sensed by the on-chip sensor;

a sensed light that is sensed by the on-chip sensor; and

a sensed gas level that is sensed by the on-chip sensor.

18 . The integrated circuit of claim 16 further comprises:

an external element port operably coupled to an external sensor that is sensing an external condition;

wherein the sensing engine is further operably coupled to:

generates a second signal representative of a sensed external condition that is sensed by the external sensor; and

generates a second digital value of the second signal.

19 . The integrated circuit of claim 16 further comprises:

calibrating the on-chip sensor at a wafer level or at a die level prior to deployment in the RFID tag to produce calibration data; and

storing the calibration data in memory of the sensing engine.

20 . The integrated circuit of claim 19 further comprises:

calibrating the on-chip sensor based on the sensed external condition and the second digital value of the signal.

21 . The integrated circuit of claim 18 further comprises:

the sensing engine is further operable to:

calibrate the generation of the signal representative of a sensed condition that is sensed by the on-chip sensor based on a table of calibration data; and/or

calibrate the generation of the second signal representative of the sensed external condition that is sensed by the external sensor based on a table of calibration data.

22 . The integrated circuit of claim 21 further comprises:

an RF receiver to receive an inbound RF signal from the RFID reader, wherein the inbound signal includes at least one calibration data point of the calibration data in the table.

23 . The integrated circuit of claim 22 further comprises:

the sensing engine storing the table of calibration data in memory of the sensing engine.

24 . A radio frequency identification (RFID) tag comprises:

a substrate;

an external antenna mounted on the substrate, wherein the external antenna, wherein the external antenna includes one or more radiating elements for electromagnetically transmitting outbound radio frequency (RF) electromagnetic signals and for electromagnetically receiving inbound RF electromagnetic signals;

an integrated circuit mounted on the substrate, wherein the integrated circuit includes:

an antenna port operable for coupling to an external antenna;

a power harvesting circuit operably coupled to the antenna port, wherein the power harvesting circuit is operable to generate an AC current from the inbound RF electromagnetic signals when the inbound RF electromagnetic signals are received via the antenna port;

a regulator operably coupled to convert the AC current into a DC operating power;

a shunt circuit coupled to shunt current of a DC voltage of the DC operating power based on a shunt threshold;

an on-chip sensor operable to sense a condition;

a sensing engine operably coupled to the on-chip sensor and to the regulator, wherein, when operational, the sensing engine:

generates a signal representative of a sensed condition that is sensed by the on-chip sensor;

generates a digital value of the signal;

generate an outbound signal that includes the digital value; and

a radio frequency (RF) transmitter is operably coupled to the antenna port and to the regulator, wherein the RF transmitter is further operably coupled to:

transmit, based on the outbound signal and via the external antenna, an outbound RF signal to an RFID reader.