Abstract: RFID technology may be used to provide digital identities for physical items. An RFID IC attached to or integrated into a physical item contains an identifier for the physical item. Digital identity information associated with the item, such as ownership information, history, properties, and the like, may be located on one or more networks. An entity, after authenticating itself and/or the item, may use the identifier to locate, retrieve, and/or update the item's digital identity information on the network.

Abstract: RFID readers may be configured to supply power to tags during frequency hops. When a reader is supplying power to a passive RFID tag via a first RF waveform having a first radio frequency and determines that it is to frequency-hop, the reader may determine whether the tag requires power during the hop. If so, the reader begins (or continues) to synthesize a second RF waveform with a second radio frequency while also synthesizing the first RF waveform, and frequency-hops by transitioning from transmitting the first RF waveform to transmitting the second RF waveform such that the power transmitted during the transition is sufficient for the tag to operate.

Abstract: A Radio Frequency Identification (RFID) reader containing a reader key authenticates an RFID tag containing a tag key by receiving a tag identifier from the tag; challenging the tag with a tag challenge; receiving a tag response based at least on the tag challenge and the tag key but not including the tag key; sending a second message including at least the tag identifier and the tag response to a verification authority; and receiving a reply from the verification authority. The reader and the verification authority may mutually authenticate each other before, during, or after the tag authentication process. The verification authority may notify a designated party if a response is incorrect.

Abstract: An authentication method includes RFID tags authenticating RFID readers. A tag sends a tag identifier and a reader challenge to a reader in response to one or more commands from the reader. The reader then either derives a response to the reader challenge itself or has a verification authority derive the response. The response may be derived from parameter(s) in the reader challenge, and may be derived using a cryptographic key. The reader then sends the response to the tag along with one or more commands. The tag verifies the response before executing action(s) associated with the command(s).

Abstract: An Integrated Circuit (IC) for an RFID tag includes at least two antenna ports for coupling to at least two antennas. The IC may be configured to determine the port from which it receives an input signal, and provide a first functionality if it receives the input from a first port and a second functionality if it receives the input from a second port. The IC may be configured to determine and/or offer a functionality based on the receiving port.

Abstract: Methods and systems are described for authorizing an item with an RFID tag to leave a facility. In one embodiment, a mobile device receives or determines an exit code (EC) to write into the tag in response to providing authorizing information. The EC may be based on information stored in the tag such as the tag's item identifier or other tag information (collectively an item identifier or II), a ticket value, other information such as the OC, a mobile identity or location, or any other suitable information. Upon verification of the EC, the tagged item is allowed to leave the facility. In another embodiment, the mobile device stores an item identifier (II) associated with the tag and provides authorizing information. Upon verifying the authorizing information and confirming that the stored II corresponds to the tagged item's II, the tagged item is allowed to leave the facility.

Abstract: Embodiments are directed to mitigating power-based impedance changes in Radio Frequency Identification (RFID) tags. The intrinsic impedance of components in an RFID tag front-end may change as incident RF power on the tag changes, causing the input impedance of the front-end to change and altering the RF properties of the RFID tag. A number of approaches can be used to mitigate input impedance variations due to power variations. One approach involves adjusting the operating point of one or more components in the RFID tag front-end to change their intrinsic impedances so as to counteract or mitigate the RF-power-based input impedance variation.

Abstract: An RFID-based item tracking system may use statistical methods to determine whether a tag or tagged item that does not respond when inventoried is present in a particular zone or reader antenna field-of-view. In one embodiment, the item tracking system may determine an observability of an item based on one or more initial trials. Upon not detecting the item in one or more subsequent trials, the item tracking system may estimate whether the item is still present based on the observability.

Abstract: RFID-tagged items can be filtered based on relevance estimation or user input. A device reads digital identifiers for multiple RFID-tagged items. The device estimates and selects an item that an individual desires based on one or more metrics, then presents data about the selected item to the individual. If the device receives feedback that the selected item is not the desired item, then the device may estimate and select another item and/or present information about multiple items to allow the individual to select the desired item. When the desired item is selected, the device may perform some associated action.

Abstract: An RFID loss-prevention system (LPS) may monitor RFID-tagged items in a facility. An RFID reader transmits a first inventory command configured to cause tags in a first state to respond, receive a reply from a first tag, determine that the first tag has a low transition risk, and cause the first tag to switch to a second state. The reader may also receive a reply from a second tag, determine that the second tag has a high transition risk, and cause the second tag to remain in the first state. The reader may then transmit a second inventory command configured to cause tags in the first state to respond, receive a reply from the second tag in response to the second inventory command, determine that the second tag has inappropriately exited the facility, and issue an alert.

Abstract: An RFID IC may operate at a relatively low clock frequency while impedance matching to an antenna is being tuned to increase the amount of power that the IC can extract from an incident RF wave. A tuning circuit tunes the impedance matching by adjusting a variable impedance coupling the IC and the antenna. The IC may power-up with a low clock frequency or reduce its current clock frequency to a lower clock frequency prior to tuning or during the tuning process, and may increase its clock frequency upon completion of tuning or during the tuning process.

Abstract: RFID readers such as synthesized-beam readers may be used to track RFID tags of interest. When a tag of interest is detected, a reader may choose to keep the tag of interest from entering a quiet state, which a detected tag may normally enter. Subsequently, the tag of interest can respond more frequently than a tag in the quiet state, allowing the reader to track any movement of the tag of interest and determine a tag trajectory. The reader may further use the determined trajectory to cooperatively-power the tag of interest.

Abstract: RFID tags capable of transitioning between a private state and one or more public states are provided. In the private state, tags may participate in an inventory round without restriction. In a public state, tags may be prevented from participating in an inventory round, allowed to participate without providing actual identifying information, or allowed to participate providing an alternate identifier. Whether and how the tag responds in a public state may depend on certain conditions including if one or more of the tag's flags are asserted or deasserted. A reader may select a public tag for inventorying by verifying itself, and the tag then asserting or deasserting one or more of its flags accordingly. The asserted or deasserted flag(s) may be used to determine whether and how a tag in a public state participates in an inventory round.

Abstract: An RFID loss-prevention system (LPS) may monitor RFID-tagged items in a facility. An RFID reader transmits a first inventory command configured to cause tags in a first state to respond, receive a reply from a first tag, determine that the first tag has a low transition risk, and cause the first tag to switch to a second state. The reader may also receive a reply from a second tag, determine that the second tag has a high transition risk, and cause the second tag to remain in the first state. The reader may then transmit a second inventory command configured to cause tags in the first state to respond, receive a reply from the second tag in response to the second inventory command, determine that the second tag has inappropriately exited the facility, and issue an alert.

Abstract: A Radio Frequency Identification (RFID) integrated circuit (IC) is at least partially covered by a repassivation layer that is, in turn, at least partially covered by a large, electrically conductive contact pad. The repassivation layer is disposed so as to leave uncovered at least one IC contact. The large contact pad is disposed so as to cover the IC IC contact. The large contact pad forms a first galvanic coupling to the IC contact and a second galvanic coupling to a tag antenna. The surface area of the first galvanic coupling is substantially smaller than the surface area of the second galvanic coupling.

Abstract: Embodiments are directed to a Radio Frequency Identification (RFID) integrated circuit (IC) having a first circuit block electrically coupled to first and second antenna contacts. The first antenna contact is disposed on a first surface of the IC and the second antenna contact is disposed on a second surface of the IC different from the first surface. A substrate of the RFID IC, or a portion of the IC substrate, electrically couples the first circuit block to at least one of the first and second antenna contacts. The IC includes one or more interfaces or barrier regions that at least partially electrically isolate the first circuit block from the rest of the IC substrate.

Abstract: An RFID integrated circuit, in addition to having conductive pads to electrically couple to an antenna, may also include a conductive bridge configured to electrically connect different portions of the antenna together. In some embodiments, the conductive bridge may be used to form a multi-turn antenna segment.

Abstract: An Integrated Circuit (IC) for an RFID tag includes at least two antenna ports for coupling to at least two antennas. The IC may be configured to determine the port from which it receives an input signal, and provide a first functionality if it receives the input from a first port and a second functionality if it receives the input from a second port. The IC may be configured to determine and/or offer a functionality based on the receiving port.

Abstract: Embodiments are directed to restricting access to Radio Frequency Identification (RFID) tag information based on location. Access to RFID tag information may be restricted at the reader level, at the requester level, and at the network level. When reader-level restrictions exist, devices may be prevented from inventorying tags and retrieving information from tags. When requester-level restrictions exist, a requester or device may be prevented from receiving tag information from inventoried tags or a network. When network-level restrictions exist, a network may discard or otherwise restrict tag information received from devices.

Abstract: Methods and systems are described for authorizing an item with an RFID tag to leave a facility. In one embodiment, a mobile device receives or determines an exit code (EC) to write into the tag in response to providing authorizing information. The EC may be based on information stored in the tag such as the tag's item identifier or other tag information (collectively an item identifier or II), a ticket value, other information such as the OC, a mobile identity or location, or any other suitable information. Upon verification of the EC, the tagged item is allowed to leave the facility. In another embodiment, the mobile device stores an item identifier (II) associated with the tag and provides authorizing information. Upon verifying the authorizing information and confirming that the stored II corresponds to the tagged item's II, the tagged item is allowed to leave the facility.