Amtech Systems, Incorporated

Tc (bermuda) License, Ltd.

Intermec IP Corporation

Tc License, Ltd.

Jeremy Landt

Kelly Gravelle

Patrick W Lunsford

Michael Melville

Charles A Johnson

Matthew K Burnett

Joseph H Kao

Tai Won Youn

Michael Paul Gonzales

A system for measuring the range to an RFID tag including situations containing high clutter and multi-path signals is disclosed. The system includes an RFID reader; an RFID tag; and a coordinated pulse compression radar system. In the system the RFID reader causes the tag to respond to received signals in a first backscatter state at a first time and a second backscatter state at a second time. The pulse compression radar system transmits short pulses coordinated by the backscatter state of the RFID tag and the system creates a differential signal comprised of the differences between radar signals obtained during the first and second states of the tag to obtain an uncorrupted measure of a round trip time of flight of said radar pulses between the pulse radar system and the RFID tag.

System and method for microwave ranging to a target in presence of clutter and multi-path effects

A system for measuring the range to an RFID tag including situations containing high clutter and multi-path signals is disclosed. The system includes an RFID reader; an RFID tag; and a coordinated pulse radar system. In the system the RFID reader causes the tag to respond to received signals in a first backscatter state at a first time and a second backscatter state at a second time. The pulsed radar system transmits short pulses coordinated by the backscatter state of the RFID tag and the system creates a differential signal comprised of the differences between radar signals obtained during the first and second states of the tag to obtain an uncorrupted measure of a round trip time of flight of said radar pulses between the pulse radar system and the RFID tag.

A system for measuring range to an RFID tag including situations containing high clutter and multi-path signals is disclosed. The system includes an RFID reader; an RFID tag; and a coordinated signal compression radar system. The reader causes the tag to respond to received signals in a first backscatter state at a first time and a second backscatter state at a second time. The signal compression radar system transmits signals coordinated by the backscatter state of the tag and creates a differential signal comprised of the differences between radar signals obtained during the first and second states of the tag to obtain an uncorrupted measure of a round trip time of flight of said radar signals between the radar system and the RFID tag. The radar may use signals typical of pulse compression radar systems such as chirp modulation or Orthogonal Frequency Domain Modulation (OFDM), either pulsed or semi-continuous.

One or more secondary data channels are added to existing RFID protocols within the existing bandwidth, data clock rate and message frame times of the protocols. An RFID system is described having at least one reader and at least one tag includes communication between the reader and the tag using a radio frequency carrier signal modulated by a modulation signal to provide a modulated carrier signal conveying digital data in either direction. The modulation signal includes a first encoded modulation signal perturbed by encoded perturbations, the first encoded modulation signal being produced from a first data string. The encoded perturbations are produced from a second data string. The modulation signal modulates the radio frequency signals to transfer data representative of the first and second data strings simultaneously between the reader and the tag. The modulation signal modulates the amplitude, phase, frequency or any combination of the radio frequency carrier signals.

Secondary data channels in RFID systems

Distance to a modulated backscatter tag is measured with a RFID reader that measures changes in phase with frequency of modulated backscattered RF signals. Measured distances are linked to a specific tag. The effects of other sources of reflected and interfering signals are mitigated. The techniques eliminate the need for high RF bandwidth used in time-of-flight methods, and may be used with linear, limiting or other types of amplifiers in the reader receiver. Unambiguous distance to a tag may be found using the derivative of phase with RF frequency of the modulated signal backscattered by a tag. The distance to a tag can be measured with an accuracy on the order of a centimeter. The techniques utilize the characteristics of cooperative backscatter tags (transponders, labels, etc.). New readers implement the techniques which may use unmodified tags.

System and method for measurement of distance to a tag by a modulated backscatter RFID reader

A radio frequency identification (RFID) device is arranged for use with a remote interrogator unit. The RFID device comprises an integrated circuit configured to send, in response to a signal received from the remote interrogator unit or automatically, a responsive signal which includes identification information. A communication antenna is electrically coupled to the integrated circuit and is provided for wireless communication with the remote interrogator unit. At least one photovoltaic cell is provided for converting radiation into electrical energy and providing power to the integrated circuit. The photocell may be designed to form all or part of the RF antenna of the RFID device.

Light activated RFID tag

The system and method for automatically controlling or configuring, a device, such as an RFID Reader, reads a master control tag to upload sets of instructions from the tag to memory resident in the reader. Thereafter, the reader may read a control tag to select one or more sets of instructions stored in memory. The reader may thus be readily programmed without the need for physically connecting the reader to a computer, and without employing expensive key pads and display screens.

System and method for automatically controlling or configuring a device, such as an RFID reader

Methods and systems for determining the direction to a transponder are disclosed. The methods and systems include transmitting a first signal to an area where communications with a transponder is desired; producing a second signal desired from the first signal; receiving the second signal via a first and second antenna forming a difference signal from the second signal received via the first and second antennas; forming a third signal by adding the second signal received via the first antenna and the second signal received via the third antenna; delaying the difference signal; and comparing a fist polarity of the delayed difference signal with a second polarity of the third signal.

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Santa Fe, NM, United States of America

Jeremy Landt