Abstract: A method includes sending, by a reader, a radio frequency (RF) signal to a wireless sensor that includes an antenna having a tail section and a head section. The tail section is for placement in an RF limited area for sensing moisture in a first location of a vehicle under test and wherein the head section is for placement in a non-RF limited area. The method further includes receiving, by the reader, an RF response to the RF signal from the wireless sensor. The first RF response includes an indication of adjustment of one or more RF characteristics of the wireless sensor, which corresponds to a variance of the one or more RF characteristics from a desired value, which, in turn, corresponds to a level of moisture at the first location. The method further includes outputting, by the reader, a message regarding the level of moisture at the first location.

Abstract: A wireless sensor includes a radio frequency (RF) front end, a sensing element, and a processing module. The RF front end receives a request for sensed data from a sensing computing device and sends a coded digital value to the sensing computing device via the RF signal. The sensing element senses an environmental condition of an item. The processing module determines an effect on an operational parameter of an RF front end of the wireless sensor as a result of the sensing element sensing the environmental condition and while receiving the RF signal. The processing module also adjusts tuning of the RF front end to mitigate the effect on the operational parameter and equates an amount of adjusting of the tuning of the RF front end to a coded digital value.

Abstract: A method includes varying, by a tuning module of a passive radio RFID sensor, a reactive component impedance coupled to the tuning module and an antenna of the passive RFID sensor in order to change a system impedance. The method further includes producing an impedance value representative of the reactive component's impedance. The method further includes storing, by a memory module of the passive RFID sensor, the impedance value, identification information corresponding to the antenna, and a timestamp corresponding to the impedance value. The method further includes communicating, by a wireless communication module of the passive RFID sensor, the impedance value, the identification information, and the timestamp to an RFID reader. When the impedance value, the identification information, and the timestamp indicate an unfavorable environmental condition, the method further includes generating, by the RFID reader, an alarm signal.

Abstract: A wireless sensor includes a substrate, an antenna, a sensing element, a transmission line, and a sensing integrated circuit (IC). The sensing element is positioned on one end of the substrate and the antenna is positioned on an opposite end of the substrate. The sensing IC is coupled to the sensing element and to the antenna via the transmission line. The sensing IC is operable to receive a sensed condition of the item from the sensing element. The sensing IC is further operable to determine an input impedance of the wireless sensor based on the sensed condition and convert it into a digital value that is representative of the condition of the item. The sensing IC is further operable to output, via the antenna, the digital value or a representation of the condition of the item.

Abstract: A method includes sending, by a reader, a radio frequency (RF) signal to a wireless sensor that includes an antenna having a tail section and a head section. The tail section is for placement in an RF limited area for sensing moisture in a first location of a vehicle under test and wherein the head section is for placement in a non-RF limited area. The method further includes receiving, by the reader, an RF response to the RF signal from the wireless sensor. The first RF response includes an indication of adjustment of one or more RF characteristics of the wireless sensor, which corresponds to a variance of the one or more RF characteristics from a desired value, which, in turn, corresponds to a level of moisture at the first location. The method further includes outputting, by the reader, a message regarding the level of moisture at the first location.

Abstract: A radio frequency identification (RFID) tag includes a power harvesting circuit, an RF front-end, and a processing module. The power harvesting circuit generates power for the RFID tag from a continuous wave of an inbound radio frequency (RF) signal. The RF front-end receives the inbound RF signal and transmits an outbound RF signal. The RF front-end includes a tuning circuit that is tuned based on a capacitance setting. The tuning of the tuning circuit effects a characteristic of the RF front-end. The processing module generate the capacitance setting to adjust the characteristic of the RF front-end to a desired characteristic.

Abstract: A power harvesting circuit, a rectifier circuit and a capacitor. The rectifier circuit includes a diode circuit and a diode voltage reduction circuit. The diode circuit passes a current when a received RF signal has a first polarity and to substantially blocks the current when the received RF signal has a second polarity. The diode voltage reduction circuit is operably coupled to reduce a voltage drop of the diode circuit. The capacitor is operably coupled to convert the rectified signal into a DC supply voltage.

Abstract: A method begins by a first radio frequency identification (RFID) sensor, that is associated with a first object element, receiving a first data request signal from an RFID reader and sending a first radio frequency (RF) signal that includes first data to the RFID reader in response to the first data request signal. The method continues with a second RFID sensor receiving a second data request signal from, and sending second data to, the RFID reader. The method continues with the RFID reader sending a representation of the first and second data to a data processing unit, which processes the representation of the first and second data to determine a first and second data point regarding first and second object elements. The method continues by the data processing unit processing the first and second data points to determine an environmental relationship between the first and second object elements.

Abstract: A radio frequency identification (RFID) tag includes an antenna, a power circuit, a tuning circuit, a receiver, and a backscatter transmitter. The power circuit is operably coupled to convert a radio frequency (RF) signal received via the antenna from an RFID reader into one or more power supply voltages. The tuning circuit is operably coupled to the antenna and to adjust an RF characteristic of the antenna and/or the tuning circuit based on a difference between a resonant frequency of the RFID tag and a carrier frequency of the RF signal. The receiver is operably coupled to receive a command signal from the RFID reader. The backscatter transmitter is operably coupled to transmit a response signal to the RFID reader via the antenna.

Abstract: A method includes varying, by a tuning module of a passive radio RFID sensor, a reactive component impedance coupled to the tuning module and an antenna of the passive RFID sensor in order to change a system impedance. The method further includes producing an impedance value representative of the reactive component's impedance. The method further includes storing, by a memory module of the passive RFID sensor, the impedance value, identification information corresponding to the antenna, and a timestamp corresponding to the impedance value. The method further includes communicating, by a wireless communication module of the passive RFID sensor, the impedance value, the identification information, and the timestamp to an RFID reader. When the impedance value, the identification information, and the timestamp indicate an unfavorable environmental condition, the method further includes generating, by the RFID reader, an alarm signal.

Abstract: A radio frequency identification (RFID) tag includes an antenna, an analog front end, a processing circuit, and memory. The analog front end includes a power circuit, a tuning circuit, a transmitter, and a receiver. The power circuit is operably coupled to convert a radio frequency (RF) signal into a power supply voltage. The tuning circuit, when enabled, adjusts an RF characteristic of the analog front end to tune power harvesting from the RF signal. The transmitter is operably coupled to transmit a response signal to the RFID reader via the antenna. The receiver is operably coupled to receive a command signal from the RFID reader, wherein the command signal is contained within a portion of the RF signal. The processing circuit is operable to interpret the command signal and generate the response signal.

Abstract: A wireless sensor includes environment sensing structure, a radio frequency (RF) front-end, and a processing module. When the wireless sensor is positioned proximal to an object, a portion of the environment sensing structure senses an environmental condition in a remote area of the object that effects a characteristic of the RF front-end. The processing module generates a reference value representative of a known environmental condition in the remote area based on the effect on the characteristic of the RF front-end. The processing module generates a sensed value representative of an unknown environmental condition in the remote area based on the effect on the characteristic of the RF front-end when the environment sensing structure is sensing the unknown environmental condition. The processing module transmits, via the RF front-end, at least one of the reference value, the sensed value, or a difference between the reference value and the sensed value.

Abstract: A method begins with a first reader sending a first radio frequency (RF) signal prior to exposing a vehicle to moisture testing. The method continues with a second reader send a second RF signal after exposing the vehicle to moisture testing. The method continues by a first RF sensor tag receiving the first RF signal and adjusting a tank circuit in response to the first RF signal to produce a first impedance change. The method continues by the first RF sensor tag generating a first digital representation of the first impedance change. The method continues by the first RF sensor tag receiving the second RF signal, adjusting the tank circuit in response to the second RF signal to produce a second impedance change, and generating a second digital representation of the second impedance change.

Abstract: A pressure sensing circuit for use with a wireless sensor that includes an antenna and a pressure sensing element. The antenna includes a first pole and a second pole and is operable to transceive radio frequency signals between the wireless sensor and a wireless data collecting device. The pressure sensing element includes an electrical circuit and a diaphragm. When pressure is applied to the diaphragm, a characteristic of the electrical circuit changes. The changing of the characteristic of the electrical circuit causes one or more RF characteristics of the wireless sensor to change, which is interpretable to determine a pressure being applied to the pressure sensing element.

Abstract: A passive radio frequency identification (RFID) sensor includes at least one antenna. The least one antenna has an antenna impedance operable to vary within an environment in which the antenna is placed. The RFID sensor further includes a processing module coupled to the antenna comprising a tuning module coupled to the antenna. The tuning module is operable to vary a reactive component impedance coupled to the antenna in order to change a system impedance, the system impedance includes the antenna impedance and the reactive component's impedance, to produce an impedance value representative of the reactive component's impedance. The RFID sensor further includes a memory module operable to store the impedance value representative of the reactive component's impedance, and a wireless communication module coupled to the processing module, operable to communicate with an RFID reader and to exchange the impedance value representative of the reactive component's impedance with the RFID reader.

Abstract: A pressure sensing circuit for use with a wireless sensor that includes an antenna and a pressure sensing element. The antenna includes a first pole and a second pole and is operable to transceive radio frequency signals between the wireless sensor and a wireless data collecting device. The pressure sensing element includes an electrical circuit and a diaphragm. When pressure is applied to the diaphragm, a characteristic of the electrical circuit changes. The changing of the characteristic of the electrical circuit causes one or more RF characteristics of the wireless sensor to change, which is interpretable to determine a pressure being applied to the pressure sensing element.

Abstract: A method begins by a first radio frequency identification (RFID) sensor, that is associated with a first object element, receiving a first data request signal from an RFID reader and sending a first radio frequency (RF) signal that includes first data to the RFID reader in response to the first data request signal. The method continues with a second RFID sensor receiving a second data request signal from, and sending second data to, the RFID reader. The method continues with the RFID reader sending a representation of the first and second data to a data processing unit, which processes the representation of the first and second data to determine a first and second data point regarding first and second object elements. The method continues by the data processing unit processing the first and second data points to determine an environmental relationship between the first and second object elements.

Abstract: A power harvesting circuit, a rectifier circuit and a capacitor. The rectifier circuit includes a diode circuit and a diode voltage reduction circuit. The diode circuit passes a current when a received RF signal has a first polarity and to substantially blocks the current when the received RF signal has a second polarity. The diode voltage reduction circuit is operably coupled to reduce a voltage drop of the diode circuit. The capacitor is operably coupled to convert the rectified signal into a DC supply voltage.

Abstract: A passive radio frequency identification (RFID) sensor is provided. This passive RFID sensor includes an inductive loop, a processing module, and a wireless communication module. The inductive loop has an inductive loop impedance that may vary with an environment in which the inductive loop is placed. The processing module couples to the inductive loop and has a tuning module that may vary a reactive component impedance coupled to the inductive loop in order to change a system impedance. The system impedance includes both the inductive loop impedance and the reactive component impedance. The tuning module then produces an impedance value representative of the reactive component impedance. A memory module may store the impedance value which may then later be communicated to an RFID reader via the wireless communication module.

Abstract: A method begins with a first reader sending a first radio frequency (RF) signal prior to exposing a vehicle to moisture testing. The method continues with a second reader send a second RF signal after exposing the vehicle to moisture testing. The method continues by a first RF sensor tag receiving the first RF signal and adjusting a tank circuit in response to the first RF signal to produce a first impedance change. The method continues by the first RF sensor tag generating a first digital representation of the first impedance change. The method continues by the first RF sensor tag receiving the second RF signal, adjusting the tank circuit in response to the second RF signal to produce a second impedance change, and generating a second digital representation of the second impedance change.