Patents Assigned to Impinj, Inc.
  • Powering RFID tags using multiple RFID readers
    Patent number: 10013587
    Abstract: Synthesized-beam RFID readers may be used to locate RFID tags. In one embodiment, a tag's response rates on different beams can be used, along with the target locations of those beams, to estimate the tag's location. The estimated tag location is within a region where beams with nonzero tag response rates overlap, and the distances of the estimated tag location from any two different beam target locations may correspond to a ratio of tag response rates on the two different beams. In another embodiment, a tag's response rates on different beam pairs configured to cooperatively power RFID tags can be used, along with the target locations of those beam pairs, to estimate the tag's location.
    Type: Grant
    Filed: January 11, 2018
    Date of Patent: July 3, 2018
    Assignee: Impinj, Inc.
    Inventors: Alberto Pesavento, Christopher J. Diorio
  • RFID tag clock frequency reduction during tuning
    Patent number: 10002266
    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.
    Type: Grant
    Filed: August 6, 2015
    Date of Patent: June 19, 2018
    Assignee: Impinj, Inc.
    Inventors: John D. Hyde, Shailendra Srinivas, Jay Kuhn, Ronald A Oliver, Harley Heinrich, Theron Stanford, Christopher J. Diorio
  • Location-based access to RFID tag information
    Patent number: 9959435
    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.
    Type: Grant
    Filed: November 23, 2016
    Date of Patent: May 1, 2018
    Assignee: IMPINJ, INC.
    Inventors: Christopher J. Diorio, Scott A. Cooper, Kurt E. Sundstrom, Todd E. Humes, Alberto Pesavento
  • RFID-based item presence detection
    Patent number: 9959494
    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.
    Type: Grant
    Filed: April 20, 2016
    Date of Patent: May 1, 2018
    Assignee: IMPINJ, INC
    Inventors: Balaji Shyamkumar, Kurt Sundstrom, Scott Cooper, Jayasuryan Iyer, Sandesh Doddameti
  • Synthesized-beam RFID reader system with gain compensation and unactivated antenna element coupling suppression
    Patent number: 9954278
    Abstract: A synthesized-beam transceiver system steers a beam of a two-dimensional antenna array by activating a first subset of antenna elements to orient the beam in a first direction and subsequently activating a second subset of the antenna elements to orient the beam in a different direction. The system also electrically connects antenna elements that are inactive, not in the first subset, or not in the second subset to a reference potential of the array.
    Type: Grant
    Filed: October 3, 2015
    Date of Patent: April 24, 2018
    Assignee: IMPINJ, INC.
    Inventors: Vincent Moretti, Omer Onen, Ronald A. Oliver
  • Enhanced RFID tag authentication
    Patent number: 9940490
    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 another command. The tag verifies the response before executing instruction(s) included in the command.
    Type: Grant
    Filed: December 13, 2013
    Date of Patent: April 10, 2018
    Assignee: IMPINJ, INC.
    Inventors: Matthew Robshaw, Harley Heinrich, Yael Maguire, Theron Stanford, Christopher J. Diorio, Scott A. Cooper
  • Sequential encoding for RFID tags
    Patent number: 9928388
    Abstract: Embodiments are directed to sequential encoding for RFID tags. An encoding line transports an RFID tag from the reading zone of a first reader to the reading zone of a second reader. The first reader communicates with the tag, writes a portion of an identifier to the tag, and sends a tag write status to the second reader. The second reader, situated after the first reader, communicates with the tag, receives the tag write status from the first reader, then determines a remaining portion of the identifier to be written to the tag based on the tag write status. The second reader then attempts to write the remaining portion to the tag. If the attempt fails, the second reader initiates an error-handling procedure.
    Type: Grant
    Filed: September 29, 2017
    Date of Patent: March 27, 2018
    Assignee: IMPINJ, INC.
    Inventors: Daniel Bowman, Kurt Sundstrom, Christopher Diorio
  • Network-enabled RFID tag endorsement
    Patent number: 9928390
    Abstract: A Radio Frequency Identification (RFID) reader may be configured to endorse an RFID tag. The reader receives an identifier from the tag and challenges the tag with a challenge. After receiving a response from the tag, the reader sends a first message including at least the identifier, challenge, and response to an authenticating entity and sends a second message including at least the identifier to a certifying entity. The reader then receives a first reply from the authenticating entity and a second reply from the certifying entity. The second reply may include a certificate associated with the tag, or may identify some property of the tag or an item associated with the tag. In some embodiments, the reader may serve as the authenticating and/or certifying entity.
    Type: Grant
    Filed: June 23, 2016
    Date of Patent: March 27, 2018
    Assignee: IMPINJ, INC
    Inventors: Christopher J. Diorio, Larry Arnstein, Scott A. Cooper
  • RFID tag location using synthesized-beam RFID readers
    Patent number: 9916484
    Abstract: Synthesized-beam RFID readers may be used to locate RFID tags. In one embodiment, a tag's response rates on different beams can be used, along with the target locations of those beams, to estimate the tag's location. The estimated tag location is within a region where beams with nonzero tag response rates overlap, and the distances of the estimated tag location from any two different beam target locations may correspond to a ratio of tag response rates on the two different beams. In another embodiment, a tag's response rates on different beam pairs configured to cooperatively power RFID tags can be used, along with the target locations of those beam pairs, to estimate the tag's location.
    Type: Grant
    Filed: May 5, 2017
    Date of Patent: March 13, 2018
    Assignee: IMPINJ, INC.
    Inventors: Alberto Pesavento, Christopher J. Diorio
  • Tag-handle-based authentication of RFID readers
    Patent number: 9916483
    Abstract: An RFID tag may execute instructions from an authenticated RFID reader. A tag determines a handle and a first parameter, both of which may be random numbers, and sends the handle to a reader. Upon receiving a challenge from the reader, the tag determines and sends a cryptographic response to the challenge based on an algorithm, a tag key, the first parameter, and the challenge. Upon receiving a message with a second parameter and a tag instruction, the tag executes the tag instruction upon verifying that the second parameter derives from the first parameter and the tag handle.
    Type: Grant
    Filed: August 18, 2017
    Date of Patent: March 13, 2018
    Assignee: IMPINJ, INC.
    Inventors: Matthew J B Robshaw, Harley Heinrich, Tan Mau Wu, Christopher Diorio
  • RFID tags with digital signature subportions
    Patent number: 9911018
    Abstract: A Radio Frequency Identification (RFID) tag integrated circuit (IC) stores a subportion of a digital signature and a subportion indicator that may be used to authenticate the IC, a tag including the IC, and/or an item associated with the tag. The subportion of the digital signature is generated, at least in part, by applying a cryptographic function to an identifier associated with the IC, the tag, and/or the item.
    Type: Grant
    Filed: September 18, 2013
    Date of Patent: March 6, 2018
    Assignee: IMPINJ, INC.
    Inventors: Harley Heinrich, Lawrence F. Arnstein, Christopher J. Diorio
  • Impedance-change mitigation in RFID tags
    Patent number: 9886658
    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.
    Type: Grant
    Filed: June 24, 2016
    Date of Patent: February 6, 2018
    Assignee: IMPINJ, INC
    Inventors: Theron Stanford, Charles J. T. Peach, Jay A. Kuhn, Harley K. Heinrich, John D. Hyde, Christopher J. Diorio, Alberto Pesavento
  • RFID tags with dynamic key replacement
    Patent number: 9887843
    Abstract: A cryptographically-enabled RFID tag stores a primary secret key and derives secondary keys from the primary key. A secondary key may be derived by combining the primary key with one or more other parameters using one or more algorithms. The tag uses a derived secondary key to encrypt or electronically sign a tag response sent to a verifying entity. The verifying entity does not know the derived secondary key, but knows the tag primary key and the parameters and algorithms used to derive the secondary key and can derive all of the potential secondary keys. The verifying entity can then attempt to authenticate the tag or tag response by trying potential secondary keys.
    Type: Grant
    Filed: December 21, 2016
    Date of Patent: February 6, 2018
    Assignee: IMPINJ, INC.
    Inventors: Matthew Robshaw, Alberto Pesavento, Christopher Diorio
  • RFID loss-prevention using angle-of-arrival
    Patent number: 9881473
    Abstract: An RFID loss-prevention system (LPS) permits authorized items to leave a facility and may perform a security action if an unauthorized item leaves the facility. A checkout reader first authorizes an item tagged with an RFID tag to exit a facility by reading an identifier from the tag, obtaining an exit authorization, and sending the identifier to a database. A reader system configured to direct at least two beams along a facility exit path reads tagged items exiting the facility, determines at least one of a travel direction and a tag location, and uses the determination to indicate that a tag is exiting or has exited the facility. The LPS then uses the database to determine if the exiting/exited tag is authorized to leave the facility.
    Type: Grant
    Filed: April 6, 2016
    Date of Patent: January 30, 2018
    Assignee: IMPINJ, INC.
    Inventors: Christopher J. Diorio, Alberto Pesavento
  • Weak RFID tag signal recovery from collisions
    Patent number: 9881186
    Abstract: RFID readers may be configured to recover weak RFID tag signals from collisions with stronger RFID tag signals. An RFID reader may receive a combined tag response including a strong tag response and a weak tag response. The reader recovers the strong and weak tag responses using source separation. In one example, the reader may recover the strong tag response from the combined tag response and remove the recovered tag response from the combined tag response to form a modified tag response. The reader may then recover the weak tag response from the modified tag response.
    Type: Grant
    Filed: June 20, 2017
    Date of Patent: January 30, 2018
    Assignee: IMPINJ, INC.
    Inventors: Kurt Eugene Sundstrom, Jayasuryan Iyer
  • RFID integrated circuits with antenna contacts on multiple surfaces
    Patent number: 9875438
    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. The first and second antenna contacts are electrically disconnected from each other.
    Type: Grant
    Filed: February 4, 2016
    Date of Patent: January 23, 2018
    Assignee: IMPINJ, INC.
    Inventors: Christopher J. Diorio, Ronald L. Koepp, Harley K. Heinrich, Theron Stanford, Ronald A. Oliver, Shailendra Srinivas
  • Inventory-cycle-based RFID tag location
    Patent number: 9852319
    Abstract: Techniques are provided to estimate the location of an RFID tag using tag read information, such as a tag read count or a tag read rate, and an opportunity metric, such as an inventory cycle duration, inventory cycle rate, or inventory cycle count. A tag tracking system determines read information for a tag in a zone and an opportunity metric associated with the tag and the zone. The tag tracking system then computes a success rate based on the tag read information and opportunity metric, and uses the success rate to estimate the location of the tag.
    Type: Grant
    Filed: July 1, 2016
    Date of Patent: December 26, 2017
    Assignee: IMPINJ, INC.
    Inventors: Alberto Pesavento, Thomas Anderl, Robert J. Ascani
  • High-speed RFID tag assembly using impulse heating
    Patent number: 9846833
    Abstract: RFID inlays or straps may be assembled using impulse heating of metal precursors. Metal precursors are applied to and/or included in contacts on an RFID IC and/or terminals on a substrate. During assembly of the tag, the IC is disposed onto the substrate such that the IC contacts physically contact either the substrate terminals or metal precursors that in turn physically contact the substrate terminals. Impulse heating is then used to rapidly apply heat to the metal precursors, processing them into metallic structures that electrically couple the IC contacts to the substrate terminals.
    Type: Grant
    Filed: July 9, 2014
    Date of Patent: December 19, 2017
    Assignee: IMPINJ, INC.
    Inventors: Ronald Lee Koepp, Harley Heinrich, Christopher J. Diorio
  • RFID loss-prevention based on transition risk
    Patent number: 9818084
    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.
    Type: Grant
    Filed: December 8, 2016
    Date of Patent: November 14, 2017
    Assignee: IMPINJ, INC.
    Inventors: Christopher J. Diorio, Alberto Pesavento
  • Sequential encoding for RFID tags
    Patent number: 9805223
    Abstract: Embodiments are directed to sequential encoding for RFID tags. An encoding line transports an RFID tag from the reading zone of a first reader to the reading zone of a second reader. The first reader communicates with the tag, writes a portion of an identifier to the tag, and sends a tag write status to the second reader. The second reader, situated after the first reader, communicates with the tag, receives the tag write status from the first reader, then determines a remaining portion of the identifier to be written to the tag based on the tag write status. The second reader then attempts to write the remaining portion to the tag. If the attempt fails, the second reader initiates an error-handling procedure.
    Type: Grant
    Filed: May 19, 2017
    Date of Patent: October 31, 2017
    Assignee: IMPINJ, INC.
    Inventors: Daniel Bowman, Kurt Sundstrom, Christopher Diorio