| Patent application number | Description | Published |
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| 20080207114 | Communications methods, methods of forming a reader, wireless communications readers, and wireless communications systems - Communications methods, methods of forming a reader, wireless communications readers, and wireless communications systems are described in some embodiments. In one embodiment, a communications method includes associating a plurality of remote communications devices with a plurality of objects located within a wireless communications range of a reader having a first configuration, providing one of the remote communications device within a wireless communications range of a reader having a second configuration, wherein the wireless communications range of the reader having the second configuration is less than the wireless communications range of the reader having the first configuration, and during the presence of the one of the remote communications devices within the wireless communications range of the reader having the second configuration, implementing communications between the reader having the second configuration and only the one of the remote communications devices. | 08-28-2008 |
| 20080211636 | Radio frequency data communications device - A radio frequency identification device includes an integrated circuit including a receiver, a transmitter, and a microprocessor. The receiver and transmitter together define an active transponder. The integrated circuit is preferably a monolithic single die integrated circuit including the receiver, the transmitter, and the microprocessor. Because the device includes an active transponder, instead of a transponder which relies on magnetic coupling for power, the device has a much greater range. | 09-04-2008 |
| 20080231421 | METHODS AND SYSTEMS OF TAGGING OBJECTS AND READING TAGS COUPLED TO OBJECTS - Methods and systems of tagging objects and reading tags coupled to objects. At least some of the illustrative embodiments are systems comprising a reading antenna, a tag reader coupled to the reading antenna, and a radio frequency identification (RFID) tag comprising a tag antenna electromagnetically coupled to the reading antenna. The RFID tag couples to an object such as the body of a living organism or a metallic article. Moreover, the tag antenna has a far-field radiation pattern in a direction away from the object that is substantially unaffected by proximity of the RFID tag to the object, and substantially unaffected by which surface of the RFID tag faces the object. | 09-25-2008 |
| 20080238684 | Multi-Antenna Element Systems and Related Methods - Multi-Antenna element systems and related methods. At least some of the illustrative embodiments comprise a radio frequency identification (RFID) tag comprising an antenna system. The antenna system comprises a ground plane, a first antenna element on a first side of the ground plane, and a second antenna element on a second side of the ground plane opposite first antenna element. The illustrative RFID tag further comprises a first radio frequency identification circuit coupled to the first antenna element. | 10-02-2008 |
| 20080238685 | METHODS AND SYSTEMS OF DETERMINING PHYSICAL CHARACTERISTICS ASSOCIATED WITH OBJECTS TAGGED WITH RFID TAGS - Methods and systems of determining physical characteristics associated with objects tagged with Radio Frequency Identification (RFID) tags. At least some of the illustrative embodiments are methods comprising making a first reading of a RFID tag coupled to an object (an electromagnetic signal received from the RFID tag having a first received signal strength indication (RSSI)), making a second reading of the RFID tag (an electromagnetic signal received from the RFID tag having a second RSSI), and a determining whether the object is moving using (at least in part) the first and second RSSI. Other illustrative embodiments, may determine (in addition to or in place of determining movement) orientation of the object based, at least in part, on the electromagnetic signals. | 10-02-2008 |
| 20080238686 | METHODS AND SYSTEMS OF DETERMINING PHYSICAL CHARACTERISTICS ASSOCIATED WITH OBJECTS TAGGED WITH RFID TAGS - Methods and systems of determining physical characteristics associated with objects tagged with Radio Frequency Identification (RFID) tags. At least some of the illustrative embodiments are methods comprising receiving an electromagnetic signal transmitted by a radio frequency identification (RFID) tag coupled to an object (the receiving the electromagnetic signal in response to an interrogating signal), and determining orientation of the object based, at least in part, on the electromagnetic signal. | 10-02-2008 |
| 20080242241 | Wireless communications systems, remote communications systems, external device circuits, wireless device communications modification methods, and wireless communications device communications methods - Some embodiments include wireless communications systems, remote communications systems, external device circuits, wireless device communications modification methods, and wireless communications device communications methods. In one embodiment, a wireless communications system includes a reader configured to output first wireless signals and to receive second wireless signals, a wireless communications device configured to receive the first wireless signals and to output the second wireless signals, wherein the first wireless signals and the second wireless signals individually include first baseband signals, and wherein the reader and the wireless communications device are individually configured to use respective ones of the first baseband signals to form respective ones of the first wireless signals and the second wireless signals, and an external circuit device electrically coupled via an electrical connection with electrical circuitry of the wireless communications device, and wherein the external circuit device is configured to communicate second baseband signals with the wireless communications device via the electrical connection. | 10-02-2008 |
| 20080266192 | METHODS AND SYSTEMS OF CHANGING ANTENNA POLARIZATION - Methods and systems of changing antenna polarization. At least some of the illustrative embodiments are systems comprising an antenna having a first feed point and a second feed point, an antenna communication circuit, and a switch assembly that selectively couples the antenna communication circuit to the first feed point, and that selectively couples the antenna communication circuit to the second feed point. The feed point (or group of feed points) is selected, for example, based on polarization of an electromagnetic wave to be radiated from or received by the antenna. | 10-30-2008 |
| 20080280560 | METHOD AND SYSTEM OF PLACING A RFID TAG IN A CONTINUOUS TRANSMISSION MODE - Method and system of placing a RFID tag in a continuous transmission mode. At least some of the illustrative embodiments are methods comprising sending a command from a radio frequency identification (RFID) reader to a first RFID tag, and then transmitting continuously by the first RFID tag based on the command. Other illustrative embodiments are RFID tags comprising a tag antenna, and a RFID circuit coupled to the tag antenna. The RFID circuit is configured to, responsive to a first command from a RFID reader, repeatedly transmit a message to the RFID reader. | 11-13-2008 |
| 20080297324 | METHODS AND SYSTEMS OF RECEIVING DATA PAYLOAD OF RFID TAGS - Methods and systems of receiving data payload of RFID tags. At least some of the illustrative embodiments are methods comprising selecting (by each of a plurality of radio frequency identification (RFID) tags) a time window within which to transmit (the selecting to create respective time windows), sending a start signal from a RFID reader to the plurality of RFID tags (the start signal indicative of the start of a first time window), and transmitting a signal by each of the plurality of RFID tags in the respective time windows. | 12-04-2008 |
| 20080315991 | METHODS AND SYSTEMS OF ATTACHING A RADIO TRANSCEIVER TO AN ANTENNA - Methods and systems of attaching a radio transceiver to an antenna. At least some of the illustrative embodiments are systems comprising an antenna and an integrated circuit configured to operate as a radio transceiver. The antenna comprises a ground plane having a first edge surface, and an active element having a second edge surface. The ground plane and the active element are retained together such that the first and second edge surfaces are substantially coplanar and form an antenna edge. The integrated circuit is configured to operate as a radio transceiver, and the integrated circuit is mechanically coupled to the edge of the antenna and electrically coupled to the active element. | 12-25-2008 |
| 20080316035 | METHOD AND SYSTEM OF ATTACHING A RFID TAG TO AN OBJECT - Methods and systems of attaching a RFID tag to an object. At least some of the illustrative embodiments are systems comprising a substrate having a pendant portion and an attachment portion, a radio frequency identification (RFID) circuit disposed on the substrate, and a tag antenna coupled to the RFID circuit and disposed on the substrate. The attachment portion of the substrate is configured to couple to an object and the pendant portion is configured to extend away from the object. | 12-25-2008 |
| 20090002165 | METHOD AND SYSTEM OF DETERMINING A LOCATION CHARACTERISTIC OF A RFID TAG - Method and system of determining a locational characteristic of a RFID tag. At least some of the illustrative embodiments are systems comprising a radio frequency identification (RFID) reader, and a phased-array reading antenna coupled to the RFID reader (the phased-array reading antenna comprising a plurality of antenna elements). The system is configured to determine a value indicative of direction of a RFID tag relative to the phased-array reading antenna based on an analysis of phase of signals induced on each of the antenna elements of the phased-array antenna by a return signal from the RFID tag. | 01-01-2009 |
| 20090015407 | RIFID TAGS AND METHODS OF DESIGNING RFID TAGS - RFID tags and methods of designing RFID tags. At least some of the illustrative embodiments are RFID tags comprising a tag antenna, a matching circuit coupled to the tag antenna, a shorting device coupled to the tag antenna and the matching circuit (wherein the shorting device is configured to selectively couple the tag antenna to common), and a tag circuit coupled to the matching circuit and the shorting device (the tag circuit configured to control the shorting device). In one or more such embodiments, a difference between a reflection coefficient of the tag antenna when the shorting device is conductive and a reflection coefficient of the tag antenna when shorting device is non-conductive is greater than or equal to approximately 0.8. | 01-15-2009 |
| 20090027168 | METHODS AND SYSTEMS OF RFID TAGS USING RFID CIRCUITS AND ANTENNAS HAVING UNMATCHED FREQUENCY RANGES - Methods and systems of RFID tags using RFID circuits and antennas having unmatched frequency ranges. At least some of the illustrative embodiments are RFID tags comprising a RFID circuit configured to operate with an antenna having a first range of resonant frequencies, a tag antenna coupled to the RFID circuit (the tag antenna having a range of resonant frequencies different than the first range of resonant frequencies, the range of resonant frequencies of the tag antenna being a second range of resonant frequencies). | 01-29-2009 |
| 20090051501 | METHODS AND SYSTEMS OF USING RADIO FREQUENCY IDENTIFICATION TAGS - Method and system of using radio frequency identification tags. At least some of the illustrative embodiments are methods comprising receiving an item for purchase, reading RFID tag on the item to identify the item at checkout, and writing data to the RFID tag indicative of parameters associated with the purchaser. | 02-26-2009 |
| 20090058648 | METHODS AND SYSTEMS OF USING RFID TAGS IN EMERGENCY SITUATIONS - Methods and systems of using RFID tags in emergency situations. At least some of the illustrative embodiments are methods comprising writing emergency information to a radio frequency identification (RFID) tag, and enabling a first responder to read the emergency information in an emergency situation. | 03-05-2009 |
| 20090058649 | SELECTIVELY COUPLING TO FEED POINTS OF AN ANTENNA SYSTEM - Selectively coupling to feed points of an antenna system. At least some of the illustrative embodiments are systems comprising an antenna system, an antenna communication circuit, a first diode coupled between the antenna communication circuit and a first feed point of the antenna system, and a second diode coupled between the antenna communication circuit and a second feed point of the antenna system. The antenna communication circuit is configured to couple the antenna communication circuit to the first and second feed points by forward biasing the diodes. | 03-05-2009 |
| 20090058657 | METHODS AND SYSTEMS USING POLARIZATION MODULATED ELECTROMAGNETIC WAVES - Methods and systems using polarization modulated electromagnetic waves. At least some of the illustrative embodiments are systems comprising a radio frequency identification (RFID) reader, and a RFID tag (the RFID tag communicatively coupled to the RFID reader),. The RFID tag is configured to transmit data to the RFID reader with data encoded in polarization of electromagnetic waves transmitted from the RFID tag. | 03-05-2009 |
| 20090091428 | Method and System to Determine Physical Parameters as Between an RFID Tag and a Reader - A method and system to determine physical parameters as between an RFID tag and a reader. At least some of the illustrative embodiments are methods comprising generating an antenna feed signal, and transmitting a first electromagnetic wave to a radio frequency device (by coupling the antenna feed signal to a reading antenna), receiving a backscattered electromagnetic wave from the radio frequency device to create a received signal, calculating a combined signal based on the antenna feed signal and received signal, and determining relative velocity between the radio frequency device and the reading antenna based on the combined signal. | 04-09-2009 |
| 20090091454 | Method and System to Determine Physical Parameters as Between A RFID Tag and a Reader - A method and system to determine physical parameters as between a RFID tag and a reader. At least some of the illustrative embodiments are methods comprising generating an antenna feed signal, and transmitting a first electromagnetic wave to a radio frequency device (by coupling the antenna feed signal to a reading antenna), receiving a backscattered electromagnetic wave from the radio frequency device to create a received signal, calculating a combined signal based on the antenna feed signal and received signal, and determining relative velocity between the radio frequency device and the reading antenna based on the combined signal. | 04-09-2009 |
| 20090214037 | Methods and Apparatuses to Secure Data Transmission in RFID Systems Against Eavesdropping - Methods and apparatuses to secure data transmission in a radio frequency identification (RFID) system and other Vernam-cipher based cryptography methods against eavesdropping. In one embodiment, a method implemented in an RFID system includes generating an encryption key using previously shared information and random information received in a current communication session and securing a communication in the current session using the encryption key. | 08-27-2009 |
| 20090257473 | RFID Fast Hop Frequency Hopping - Methods and apparatus, including computer program products, for RFID fast hop frequency hopping. A method including transmitting from a radio frequency identification (RFID) interrogator a continuous wave un-modulated radio frequency (RF) signal from a frequency synthesizer based on digital waveform reconstruction with Direct Memory Access (DMA), the continuous wave un-modulated RF signal conforming to a fast hop frequency hopping protocol in which each hop of a plurality of hops spans at least one bit but less than the totality of bits to be sent from a single RFID device data in a single communications session. | 10-15-2009 |
| 20090257474 | Fast hop frequency hopping protocol - Methods and apparatus, including computer program products, for a fast hop frequency hopping protocol. A method includes transmitting from a radio frequency identification (RFID) interrogator a continuous wave un-modulated radio frequency (RF) signal conforming to a fast hop frequency hopping protocol in which each hop of a plurality of hops spans at least one bit but less than the totality of bits to be sent from a single RFID device data in a single communications session. | 10-15-2009 |
| 20090266896 | Methods and Systems of Attaching a Radio Transceiver to an Antenna - Methods and systems of attaching a radio transceiver to an antenna. At least some of the illustrative embodiments are systems comprising an antenna and an integrated circuit configured to operate as a radio transceiver. The antenna comprises a ground plane having a first edge surface, and an active element having a second edge surface. The ground plane and the active element are retained together such that the first and second edge surfaces are substantially coplanar and form an antenna edge. The integrated circuit is configured to operate as a radio transceiver, and the integrated circuit is mechanically coupled to the edge of the antenna and electrically coupled to the active element. | 10-29-2009 |
| 20090278688 | RFID Devices Using RFID Circuits and Antennas Having Unmatched Frequency Ranges - An RFID system in which RFID devices utilize RFID circuits and antennas having unmatched frequency ranges. The system includes an RFID interrogator having multiple interrogator antennas. Each interrogator antenna can be tuned to different respective frequency ranges. The system includes an RFID device having an RFID circuit, and device antennas coupled to the RFID circuit. Each device antenna can be tuned to a respective frequency range that matches only one of the interrogator antennas for communicating with the RFID interrogator according to respective protocols associated with each respective frequency range. | 11-12-2009 |
| 20090289771 | RFID Device Using Single Antenna For Multiple Resonant Frequency Ranges - An RFID device utilizing a single antenna for multiple resonant frequency ranges. RFID device that can include an RFID circuit, and a single antenna coupled to the RFID circuit. The antenna can be configured to operate within multiple frequency ranges for communicating with at least one RFID interrogator according to respective protocols associated with each respective frequency range. | 11-26-2009 |
| 20090303004 | Systems and Methods to Determine Motion Parameters using RFID Tags - Systems and methods to determine motion parameters of physical objects using radio frequency identification (RFID) tags attached to the objects. In one embodiment, a method implemented in a radio frequency identification (RFID) system includes determining a motion parameter of the RFID tag based on detecting a Doppler frequency shift in a radio frequency signal received from the RFID tag. | 12-10-2009 |
| 20090303005 | Systems and Methods to Determine Kinematical Parameters using RFID Tags - Systems and methods to determine kinematical parameters of physical objects using radio frequency identification (RFID) tags attached to the objects. In one embodiment, one of a population of RFID tags is selectively instructed by an RFID reader to backscatter the interrogating electromagnetic wave and thus allow the RFID reader to measure the position, speed, acceleration, jerk of the object to which the tag is attached. The RFID reader combines the signal representing the backscattered interrogating electromagnetic wave and the signal representing the interrogating electromagnetic wave transmitted by the RFID reader to determine or monitor one or more of the kinematical parameters of the object. | 12-10-2009 |
| 20090315683 | Analog RFID System - Methods and apparatus, including computer program products, for an analog RFID system. A radio frequency identification (RFID) device includes an antenna linked to an integrated circuit, the integrated circuit comprising tag circuitry and analog modulation circuitry, a device linked to the integrated circuit, the device generating an analog signal output, and the analog modulation circuitry configured to conditioning the analog signal output. | 12-24-2009 |
| 20100073139 | Electronic Monitoring Systems, Shipment Container Monitoring Systems and Methods of Monitoring a Shipment in a Container - A shipping container has a passive radio antenna element having internal and external antennas. A connector spanning the wall joins the two antennas. An internal communications device is disposed within the container and an external communications device is disposed external to the container. Another shipping container has a repeater element having internal and external antennas. A repeater unit spans the wall joining the two antennas. A communications device is disposed within the container and another communications device is disposed externally. RF signals are re-radiated by the antennas. Methodology includes emitting RF signals from a communication device disposed at a first location, receiving the signals through an antenna comprised by an antenna element, and re-radiating the signal from a second antenna comprised by the element, where the element spans the wall of a shipping container. The re-radiated signal is received by a second communications device disposed at a second location. | 03-25-2010 |
| 20110032171 | METHODS AND SYSTEMS OF CHANGING ANTENNA POLARIZATION - A switch assembly selectively couples an antenna communication circuit to a first feed point of a first antenna, and selectively couples the antenna communication circuit to a second feed point of a second antenna. Each feed point is selected based on polarization of an electromagnetic wave to be radiated from or received by the corresponding antenna. | 02-10-2011 |
| 20110084808 | TRACKING SYSTEMS, METHODS OF LOCATING AND IDENTIFYING RFIDS, AND METHODS OF TRACKING ITEMS - Some embodiments include observable properties triggered upon interrogation of RFIDs. The RFIDs can be passive RFIDs, and the observable properties can be visible changes that require little power to generate, and little or no power to maintain. The visible information can include information about items tracked with the RFIDs, such as shipping information. Some embodiments include passive RFIDs utilizing a single antenna to power an integrated-circuit chip and a visual identifier. Some embodiments include methods of locating interrogated RFIDs. Some embodiments include methods of tracking items. | 04-14-2011 |
| 20110193685 | RFID COMMUNICATION SYSTEMS AND METHODS, AND RFID READERS AND SYSTEMS - A method of coordinating a plurality of RFID readers includes controlling the RFID readers such that only one of the readers performs an inventory of RFID tags at a time. A system for coordinating a plurality of RFID readers is also provided. | 08-11-2011 |
| 20110253792 | FLEXIBLE RFID LABEL - An RFID tag includes a base having at least one fold formed therein. An integrated circuit is formed on the base. At least one antenna segment extends from the integrated circuit and crosses the fold. When the fold is creased, a portion of the antenna segment on one side of the fold is aligned to be orthogonal to a portion of the antenna segment on the other side of the fold. | 10-20-2011 |
| 20110260835 | METHODS AND SYSTEMS OF TAGGING OBJECTS AND READING TAGS COUPLED TO OBJECTS - Methods and systems of tagging objects and reading tags coupled to objects. At least some of the illustrative embodiments are systems comprising a reading antenna, a tag reader coupled to the reading antenna, and a radio frequency identification (RFID) tag comprising a tag antenna electromagnetically coupled to the reading antenna. The RFID tag couples to an object such as the body of a living organism or a metallic article. Moreover, the tag antenna has a far-field radiation pattern in a direction away from the object that is substantially unaffected by proximity of the RFID tag to the object, and substantially unaffected by which surface of the RFID tag faces the object. | 10-27-2011 |
| 20110260838 | SYSTEMS AND METHODS FOR RFID TAG ARBITRATION WHERE RFID TAGS GENERATE MULTIPLE RANDOM NUMBERS FOR DIFFERENT ARBITRATION SESSIONS - A radio frequency identification device (RFID) tag includes a processor, a memory configured to store an identification number that distinguishes the tag from other tags, and a transponder coupled to the memory and the processor. The tag arbitrates by selecting a random number in response to an inventory query from a reader. The tag responds to the reader depending on the random number selected. The tag is configured for multiple concurrent inventory session arbitrations with multiple readers by separately storing random numbers for respective inventory session arbitrations. | 10-27-2011 |
| 20110273362 | ELECTRONIC MONITORING SYSTEMS, SHIPMENT CONTAINER MONITORING SYSTEMS AND MEHTODS OF MONITORING A SHIPMENT IN A CONTAINER - A shipping container has a passive radio antenna element having internal and external antennas. A connector spanning the wall joins the two antennas. An internal communications device is disposed within the container and an external communications device is disposed external to the container. Another shipping container has a repeater element having internal and external antennas. A repeater unit spans the wall joining the two antennas. A communications device is disposed within the container and another communications device is disposed externally. RF signals are re-radiated by the antennas. Methodology includes emitting RF signals from a communication device disposed at a first location, receiving the signals through an antenna comprised by an antenna element, and re-radiating the signal from a second antenna comprised by the element, where the element spans the wall of a shipping container. The re-radiated signal is received by a second communications device disposed at a second location. | 11-10-2011 |
| 20110279232 | SYSTEMS AND METHODS TO SELECTIVELY CONNECT ANTENNAS TO RECEIVE AND BACKSCATTER RADIO FREQUENCY SIGNALS - Systems and methods to selectively attach and control antennas via diodes and current sources. In one embodiment, a system includes: an RFID reader having a plurality of reader antennas of different polarizations to transmit radio frequency signals; and at least one RFID tag. The RFID tag includes: a plurality of tag antennas of different polarizations; a plurality of diodes coupled to the plurality of tag antennas respectively; a receiver coupled to the plurality of diodes to receive the radio frequency signals from the tag antennas when the diodes are forward biased; and a set of one or more current controllers coupled to the plurality of diodes. In a receiving mode the controllers selectively forward bias the diodes to receive the signals from the RFID reader. In a transmitting mode the controllers selectively change the state of the tag antennas to transmit data via backscattering the radio frequency signals. | 11-17-2011 |
| 20120061477 | Systems and Methods to Selectively Connect Antennas to Receive and Backscatter Radio Frequency Signals - Systems and methods to selectively attach and control antennas via diodes and current sources. In one embodiment, a system includes: an RFID reader having a plurality of reader antennas of different polarizations to transmit radio frequency signals; and at least one RFID tag. The RFID tag includes: a plurality of tag antennas of different polarizations; a plurality of diodes coupled to the plurality of tag antennas respectively; a receiver coupled to the plurality of diodes to receive the radio frequency signals from the tag antennas when the diodes are forward biased; and a set of one or more current controllers coupled to the plurality of diodes. In a receiving mode the controllers selectively forward bias the diodes to receive the signals from the RFID reader. In a transmitting mode the controllers selectively change the state of the tag antennas to transmit data via backscattering the radio frequency signals. | 03-15-2012 |
| 20120218083 | METHODS AND APPARATUSES TO SECURE DATA TRANSMISSION IN RFID SYSTEMS - Methods and apparatuses to secure data transmission in a radio frequency identification (RFID) system against eavesdropping, using multiple communication channels. In one embodiment, a method includes communicating key information and cipher text generated based on the key information, or plain text, using a plurality of different, distinct and separate communication channels connected to an RFID tag. | 08-30-2012 |
| 20120268253 | Systems and Methods to Determine Motion Parameters Using RFID Tags - Systems and methods to determine motion parameters of physical objects using radio frequency identification (RFID) tags attached to the objects. In one embodiment, a method implemented in a radio frequency identification (RFID) system includes determining a motion parameter of the RFID tag based on detecting a Doppler frequency shift in a radio frequency signal received from the RFID tag. | 10-25-2012 |
| 20120268254 | METHOD AND SYSTEMS OF TAGGING OBJECTS AND READING TAGS COUPLED TO OBJECTS - Methods and systems of tagging objects and reading tags coupled to objects. At least some of the illustrative embodiments are systems comprising a reading antenna, a tag reader coupled to the reading antenna, and a radio frequency identification (RFID) tag comprising a tag antenna electromagnetically coupled to the reading antenna. The RFID tag couples to an object such as the body of a living organism or a metallic article. Moreover, the tag antenna has a far-field radiation pattern in a direction away from the object that is substantially unaffected by proximity of the RFID tag to the object, and substantially unaffected by which surface of the RFID tag faces the object. | 10-25-2012 |
| 20120268308 | Systems and Methods to Use Radar in RFID Systems - Systems and methods to use radar systems for radio frequency identification (RFID) applications. In one embodiment, radar systems are adapted to use RFID communications protocols and methods to enhance the usefulness of radar systems beyond the determination of the presence, distance, direction and/or speed of a vehicle or object, to additionally include the transmission of data such as object identification and additional messages or data. | 10-25-2012 |
| 20130168455 | SYSTEMS AND METHODS TO SELECTIVELY CONNECT ANTENNAS TO RECEIVE AND BACKSCATTER RADIO FREQUENCY SIGNALS - Systems and methods to selectively attach and control antennas via diodes and current sources. In one embodiment, a system includes: an RFID reader having a plurality of reader antennas of different polarizations to transmit radio frequency signals; and at least one RFID tag. The RFID tag includes: a plurality of tag antennas of different polarizations; a plurality of diodes coupled to the plurality of tag antennas respectively; a receiver coupled to the plurality of diodes to receive the radio frequency signals from the tag antennas when the diodes are forward biased; and a set of one or more current controllers coupled to the plurality of diodes. In a receiving mode the controllers selectively forward bias the diodes to receive the signals from the RFID reader. In a transmitting mode the controllers selectively change the state of the tag antennas to transmit data via backscattering the radio frequency signals. | 07-04-2013 |
| 20130241708 | SYSTEMS AND METHODS TO DETERMINE KINEMATICAL PARAMETERS USING RFID TAGS - Systems and methods to determine kinematical parameters of physical objects using radio frequency identification (RFID) tags attached to the objects. In one embodiment, one of a population of RFID tags is selectively instructed by an RFID reader to backscatter the interrogating electromagnetic wave and thus allow the RFID reader to measure the position, speed, acceleration, jerk of the object to which the tag is attached. The RFID reader combines the signal representing the backscattered interrogating electromagnetic wave and the signal representing the interrogating electromagnetic wave transmitted by the RFID reader to determine or monitor one or more of the kinematical parameters of the object. | 09-19-2013 |
| 20140104042 | SYSTEMS AND METHODS TO DETERMINE MOTION PARAMETERS USING RFID TAGS - Systems and methods to determine motion parameters of physical objects using radio frequency identification (RFID) tags attached to the objects. In one embodiment, a method implemented in a radio frequency identification (RFID) system includes determining a motion parameter of the RFID tag based on detecting a Doppler frequency shift in a radio frequency signal received from the RFID tag. | 04-17-2014 |
