Abstract: Provided are RFID systems, methods and RFID tags according to various aspects. An infrared (IR) beam, from an IR transmitter, is outputted in a first direction so that an RFID tag with an IR sensor adds a flag to stored data in the RFID tag in response to the RFID tag's IR sensor detecting the IR beam. An RF interrogation signal is outputted by an RFID reader, and a response is received from the RFID tag to the RF interrogation signal. It is determined whether the flag is contained in the RFID tag's response to the RF interrogation signal, and if so, the RFID tag is determined to be in the first direction relative to the IR transmitter.

Abstract: A radio frequency identification (RFID) transponder may include a substrate and a device. The substrate may be in communication with a controller and an antenna, and the antenna is arranged to receive radio frequency signals. A first side surface of the substrate may include a capacitor. The device may be detachably coupled with the substrate via a conductive member positioned between the structure and the capacitor of the substrate, and the conductive member may be within a desired proximity of the capacitor. The structure may be attached to an attachment surface so that an attachment strength between the structure and the attachment surface may be greater than a force required to decouple the structure from the substrate. When the structure is decoupled from the substrate, the conductive member separates from the capacitor, disabling the transponder.

Abstract: A system and method for powering and communicating with wireless sensors are provided. One system includes a radio-frequency (RF) transmitter configured to transmit at least one of RF power signals or RF communication signals and a coupling circuit configured to couple the RF transmitter to electrical wiring to allow transmission of the RF power signals or the RF communication signals through the electrical wiring. The system also includes a connector configured to couple the RF transmitter to a power outlet of the electrical wiring.

Abstract: A radio frequency identification (RFID) transponder may include a substrate and a device. The substrate may be in communication with a controller and an antenna, and the antenna is arranged to receive radio frequency signals. A first side surface of the substrate may include a capacitor. The device may be detachably coupled with the substrate via a conductive member positioned between the structure and the capacitor of the substrate, and the conductive member may be within a desired proximity of the capacitor. The structure may be attached to an attachment surface so that an attachment strength between the structure and the attachment surface may be greater than a force required to decouple the structure from the substrate. When the structure is decoupled from the substrate, the conductive member separates from the capacitor, disabling the transponder.

Abstract: A system for determining a bearing or location of a radio frequency identification (RFID) tag using a handheld RFID reader is described. In one embodiment, the reader is equipped with an accelerometer. A user moves the reader while the reader receives the tag's signal and determines the tag signal's phase at multiple locations. The locations of the reader antenna can be reconstructed using the accelerometer data. By using the phase determined at multiple locations in conjunction with the location of the reader antenna, the reader can determine the bearing of the tag. For an RFID reader not equipped with an accelerometer, the sign and ratio of the rate of change in the phase of a tag's signal to the distance traveled by the reader antenna can be used to determine the location of the tag relative to the reader.

Abstract: A system for determining a bearing or location of a radio frequency identification (RFID) tag using a handheld RFID reader is described. In one embodiment, the reader is equipped with an accelerometer. A user moves the reader while the reader receives the tag's signal and determines the tag signal's phase at multiple locations. The locations of the reader antenna can be reconstructed using the accelerometer data. By using the phase determined at multiple locations in conjunction with the location of the reader antenna, the reader can determine the bearing of the tag. For an RFID reader not equipped with an accelerometer, the sign and ratio of the rate of change in the phase of a tag's signal to the distance traveled by the reader antenna can be used to determine the location of the tag relative to the reader.

Abstract: Provided are RFID systems, methods and RFID tags according to various aspects. An infrared (IR) beam, from an IR transmitter, is outputted in a first direction so that an RFID tag with an IR sensor adds a flag to stored data in the RFID tag in response to the RFID tag's IR sensor detecting the IR beam. An RF interrogation signal is outputted by an RFID reader, and a response is received from the RFID tag to the RF interrogation signal. It is determined whether the flag is contained in the RFID tag's response to the RF interrogation signal, and if so, the RFID tag is determined to be in the first direction relative to the IR transmitter.

Abstract: A smart tag reading system is provided that has the ability to query sensor tags that have energy harvesting capability. In one embodiment, an adaptive reader system learns the state of each tag and how long the tag takes to charge. Tags that charge relatively quickly can be accessed more frequently. Others that do not charge as quickly, readings can be performed at much longer intervals allowing the tag a longer time to gather enough energy to complete the transaction. The reader query system can then adapt to the environment and state of the individual tags.

Abstract: A system, method and computer readable medium are provided. One system includes a transmit antenna, at least one receive antenna, and an imager configured to acquire one or more images in a scanning area having one or more radio frequency identifier (RFID) tags including an RFID tag of interest. The system further includes a controller configured to operate the transmit antenna and the at least one receive antenna to acquire location information from the RFID tags, wherein the controller is further configured to operate the imager to acquire the images while the location information is acquired. The system includes a processor configured to correlate the acquired location information and the one or more images to determine an image corresponding to a location of the RFID tag of interest. The system additionally includes a display configured to display the image corresponding to the location of the RFID tag of interest.

Abstract: A method of addressing one or more RFID devices within a group of RFID devices includes transmitting a command to respond to the group at a first modulation depth. The method further includes receiving a response from a first sub-group of RFID devices in the group that have a minimum modulation depth less than or equal to the first modulation depth. The method further includes transmitting the command to respond to the group at a second modulation depth higher than the first modulation depth. The method further includes receiving a response from a second sub-group of RFID devices within the group that have a minimum modulation depth less than or equal to the second modulation depth. The method is also directed to authenticating RFIDs by comparing a measured minimum modulation depth to a known minimum modulation depth.

Abstract: A radio frequency identification (RFID) transponder may include a substrate and a device. The substrate may be in communication with a controller and an antenna, and the antenna is arranged to receive radio frequency signals. A first side surface of the substrate may include a capacitor. The device may be detachably coupled with the substrate via a conductive member positioned between the structure and the capacitor of the substrate, and the conductive member may be within a desired proximity of the capacitor. The structure may be attached to an attachment surface so that an attachment strength between the structure and the attachment surface may be greater than a force required to decouple the structure from the substrate. When the structure is decoupled from the substrate, the conductive member separates from the capacitor, disabling the transponder.

Abstract: A distance between at least one antenna of an interrogation system and a transponder, such as an RFID tag, is determined based on derivatives with respect to frequency of the phase and the signal strength of responses transmitted by the transponder and received at the at least one antenna. The derivatives of the phase and the signal strength facilitate compensating for sources of multipath interference. Determining changes in distance may further facilitate determining location, speed, or bearing of the transponder by the interrogation system.

Abstract: A system for determining a bearing or location of a radio frequency identification (RFID) tag using a handheld RFID reader is described. In one embodiment, the reader is equipped with an accelerometer. A user moves the reader while the reader receives the tag's signal and determines the tag signal's phase at multiple locations. The locations of the reader antenna can be reconstructed using the accelerometer data. By using the phase determined at multiple locations in conjunction with the location of the reader antenna, the reader can determine the bearing of the tag. For an RFID reader not equipped with an accelerometer, the sign and ratio of the rate of change in the phase of a tag's signal to the distance traveled by the reader antenna can be used to determine the location of the tag relative to the reader.

Abstract: A distance between at least one antenna of an interrogation system and a transponder, such as an RFID tag, is determined based on derivatives with respect to frequency of the phase and the signal strength of responses transmitted by the transponder and received at the at least one antenna. The derivatives of the phase and the signal strength facilitate compensating for sources of multipath interference. Determining changes in distance may further facilitate determining location, speed, or bearing of the transponder by the interrogation system.

Abstract: A system for determining a bearing or location of a radio frequency identification (RFID) tag using a handheld RFID reader is described. In one embodiment, the reader is equipped with an accelerometer. A user moves the reader while the reader receives the tag's signal and determines the tag signal's phase at multiple locations. The locations of the reader antenna can be reconstructed using the accelerometer data. By using the phase determined at multiple locations in conjunction with the location of the reader antenna, the reader can determine the bearing of the tag. For an RFID reader not equipped with an accelerometer, the sign and ratio of the rate of change in the phase of a tag's signal to the distance traveled by the reader antenna can be used to determine the location of the tag relative to the reader.

Abstract: Passive wireless transponders can perform transponder-to-transponder communication when illuminated by an interrogation carrier wave. The transponder-to-transponder communication permits each transponder to determine the identity of “other” proximately transponders. The transponder-to-transponder communication optionally permits each transponder to identify a “nearest neighbor” using one or more backscatter signal properties such as received signal strength or time-of-flight. Using this information and one or more externally supplied or internally stored instruction sets transponders can provide neighboring transponder data to an interrogator. Using this “neighbor” data, the interrogator can provide a system user with data indicative of the relative locations of a plurality of tags arranged in a one or two dimensional matrix.

Abstract: A reconfigurable antenna element is controlled using a wirelessly powered and wirelessly activated switch, where the antenna element is part of an antenna or antenna array. A control signal for reconfiguring the antenna element is embedded into a wirelessly transmitted data signal for transmission by the antenna.

Abstract: A total number of transponders in an interrogation field is estimated or determined based on demodulated baseband direct and quadrature components from a plurality of collided responses from multiple transponders, including collided responses from which information encoded therein cannot be recovered, and would conventionally be discarded. A query or Q value may be set without an a priori knowledge of the actual number or even approximate number of transponders in the field of the interrogator or reader. Such may allow transponders to be quickly and efficiently singulated, for example in a single pass, and information read from and/or written to singulated transponders.

Abstract: A system for determining a bearing or location of a radio frequency identification (RFID) tag using a handheld RFID reader is described. In one embodiment, the reader is equipped with an accelerometer. A user moves the reader while the reader receives the tag's signal and determines the tag signal's phase at multiple locations. The locations of the reader antenna can be reconstructed using the accelerometer data. By using the phase determined at multiple locations in conjunction with the location of the reader antenna, the reader can determine the bearing of the tag. For an RFID reader not equipped with an accelerometer, the sign and ratio of the rate of change in the phase of a tag's signal to the distance traveled by the reader antenna can be used to determine the location of the tag relative to the reader.

Abstract: Data carriers (such as RFID tags) are formed into clusters of data carriers. Each cluster has at least one bridge data carrier that can communicate with a bridge data carrier of another cluster, thereby allowing data carriers in each cluster to communicate directly or indirectly with each other using a stochastic communication protocol method. Direct tag-to-tag communication capability is provided between data carriers in each cluster and/or between clusters. The data carriers can backscatter and modulate a carrier wave from a source, thereby using the backscattered and modulated carrier wave to convey data to each other.