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.

Abstract: A radio frequency identification (RFID) reader outputs an interrogation signal, and hops/varies the phase of the interrogation signal sent by the RFID reader over time. Varying the phase of the interrogation signal enables the RFID reader to provide, for each zone of an RF field of the RFID reader, a particular phase that reduces of the effects of interference RF signal(s) present in that zone of the RF field. Reducing the interference in each zone of the RF field increases the throughput of RFID tags that can be successfully read by the RFID reader.

Abstract: In systems and methods for determining the placement of radio-frequency identification (RFID) tags, a tag reader communicates with one or more RFID tags at different locations of a target object. The tag reader determines which of the different locations is a preferable location for placing an RFID tag by detecting the transmission power level or other value required to communicate with the RFID tag at each of the different locations.

Abstract: A wireless encoder for encoding a plurality of wireless communication devices carried by media comprises a shielded enclosure having an exterior surface defining an aperture; a wireless signal generator to excite the shielded enclosure; and a media path along which media carrying a plurality of wireless communication devices travels. The media path passes across the aperture outside the shielded enclosure.

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.

Abstract: A method and system of determining spatial identification of an object, such as orientation, size, location, range, and/or movement, using an RFID system is disclosed. An RFID system can comprise one or more RFID reader receiving antennas that query one or more RFID tags coupled to the object. The measurement of the phase of the tag responses at the reader antennas and phase differentials as a function of distance, frequency, and time are the basis of spatial identification. The system can work with conventional Gen 2 tags and readers without modification of the tags or protocol.

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: 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.

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: Spatial antenna diversity is used with RFID tags to reduce sensitivity to multi-path fading. RFID tags can use a single multi-port chip or multiple multi-port chips. The ports of the chip or chips are coupled to separated feedpoints on one or more antennas.

Abstract: A radio frequency identification system comprises a radio-frequency identification substrate and an interrogator. In one embodiment, the radio-frequency identification substrate comprises a plurality of radio-frequency identification devices. In one embodiment, a controller on the substrate controls a first one of the plurality of radio-frequency identification devices based on a state of a second one of the plurality of radio-frequency identification devices. In one embodiment, an antenna system includes an S-shaped portion electrically coupled to an integrated circuit along a central portion of the S-shaped portion. Adjusting the parameters of the segments making up the S-shaped portion controls performance characteristics of a radio-frequency identification device.

Abstract: This disclosure discloses methods and apparatus for detecting and characterizing radio-frequency identification (RFID) tags.

Abstract: A multi-band and/or multi-protocol, configurable, RFID tag is provided. The tag can include one or more electrical or mechanical selectors for selecting from among multiple frequency bands and communication protocols. In some embodiments, a signal band and protocol can be detected automatically and selection among bands and protocols can be performed automatically. In some embodiments, one or more externally accessibly switches can be actuated by a user to select a band and/or protocol.

Abstract: A radio frequency identification system comprises a radio-frequency identification substrate and an interrogator. In one embodiment, the radio-frequency identification substrate comprises a plurality of radio-frequency identification devices. In one embodiment, a controller on the substrate controls a first one of the plurality of radio-frequency identification devices based on a state of a second one of the plurality of radio-frequency identification devices. In one embodiment, an antenna system includes an S-shaped portion electrically coupled to an integrated circuit along a central portion of the S-shaped portion. Adjusting the parameters of the segments making up the S-shaped portion controls performance characteristics of a radio-frequency identification device.

Abstract: A method and system of determining spatial identification of an object, such as orientation, size, location, range, and/or movement, using an RFID system is disclosed. An RFID system can comprise one or more RFID reader receiving antennas that query one or more RFID tags coupled to the object. The measurement of the phase of the tag responses at the reader antennas and phase differentials as a function of distance, frequency, and time are the basis of spatial identification. The system can work with conventional Gen 2 tags and readers without modification of the tags or protocol.

Abstract: Systems, methods, and devices wirelessly communicate in a near-field region and a far-field region. A device may include a near-field antenna and a far-field antenna. The device may be configured to selectively operate in a near-field mode, employing the near-field antenna, and/or in a far-field mode, employing the far-field antenna, and/or in a joint mode, employing both the near-field antenna and the far-field antenna separately or concurrently. One type of device may be a wireless communications data-reader device configured for both near-field and far-field communications. Another type of device may be a wireless communications data-provider device configured for both near-field and far-field communications.

Abstract: A media marking transponder system includes a media fastener and a wireless transponder circuit coupled to the media fastener. The antenna for the wireless transponder circuit has a first effective length when no piece of media is fastened to the media fastener and a second, different effective length when at least one piece of media is fastened to the media fastener.

Abstract: A wireless transponder system includes at least one antenna configured to send transponder signals. The wireless transponder system also includes a wireless transponder circuit coupled to the at least one antenna, the wireless transponder circuit having a first state for sending transponder signals of a first polarization type and a second state for sending transponder signals of a second polarization type different than the first polarization type, and the wireless transponder circuit configured to encode information in a sequence of the transponder signals of the first polarization type alternating with the transponder signals of the second polarization type.