Symbol Technologies, LLC

Martin J Strzelczyk

Mark William Duron

Sean A Connolly

Raj Bridgelall

Mohammad Soleimani

David E Bellows

Richard T Knadle

Robert I Sandler

Ian D Chamberlin

Son Truong Ngo

Victor Hugo Molina

Jens Arnold

Albert Owens

Ron Boschini

Darrell Pinson

A method and system for adaptive operation of a power amplifier of an RFID reader device enables more efficient power management of the reader device. The method includes transmitting an RF interrogation signal from an antenna of the RFID reader device (step). A reflected signal is then received as a partial reflection of the interrogation signal (step). A return loss value is then estimated by comparing at least one parameter of the interrogation signal and at least one parameter of the reflected signal (step). Finally, an operating point of the power amplifier is adjusted in response to the return loss value (step).

Method and system for adaptive operation of a power amplifier of a radio frequency identification (RFID) reader device

A method and device enables reading radio frequency identification (RFID) tags in a localized area. The method according to one embodiment includes commencing transmission of an interference signal from a reader device (step). A command signal is then transmitted from the device while the interference signal is still being transmitted (step). The command signal instructs non-target RFID tags to not respond to an interrogation signal, and the target RFID tags do not process the command signal because the command signal is blocked by the interference signal. Transmission of the interference signal from the device is then stopped (step). The interrogation signal is then transmitted from the device after the interference signal is no longer being transmitted (step). Finally, a response signal is received at the device from the target RFID tags that enables the device to read only the target RFID tags (step).

Method and device for reading radio frequency identification (RFID) tags

A method and device enables improving a signal to noise ratio (SNR) of a backscatter signal received from a radio frequency identification (RFID) tag. The method includes generating a continuous wave (CW) carrier signal at the reader device (step). An amplitude modulation (AM) noise component of the CW carrier signal is then detected (step). The AM noise component is inverted to an inverted noise signal (step), and the inverted noise signal is summed with the CW carrier signal to provide an AM noise cancelled carrier signal (step). The AM noise cancelled carrier signal is then transmitted from an antenna of the reader device (step), and the backscatter signal is received at the reader device in response to transmission of the AM noise cancelled carrier signal (step).

Method and device for improving the signal to noise ratio (SNR) of a backscatter signal received from a radio frequency identification (RFID) tag

A system and methods for measuring the temperature of an RFID reader module and inserting a delay in the RFID reader's duty cycle to prevent the RFID reader from initiating a thermal shutdown. The system and methods are self-adaptable, therefore incurring the benefit regardless of the design of the RFID reader host and its associated heat sink. The system and methods also provide for archiving the collected data and analyzing the data providing the ability to improve the design of the RFID reader host.

Thermally controlled duty cycle regulation in an RFID module

Described herein are methods, devices and systems for characterizing an attached antenna to an electronic device, such as a radio frequency identification ('RFID') reader. One exemplary embodiment is related to a method comprising outputting a low amplitude modulation ('AM') index radio frequency (&#x201c;RF&#x201d;) waveform, the waveform simulating tag data timing and bandwidth, removing a direct current (&#x201c;DC&#x201d;) component from the waveform to create a chopped portion of the waveform, applying at least one vector analyzer technique on the chopped portion of the waveform, characterizing at least one antenna impedance vector of the waveform.

Method and system for chopped antenna impedance measurements with an RFID radio

A thermal management system and method to control temperature in an RFID reader is described herein. In particular, by inserting variable periods of inactivity (or latency) at the beginning or at the end of each read cycle, proportional to an instantaneous temperature value of the RFID reader, over-heating and damage of RFID reader electronics is prevented. The RFID reader includes a thermal sensor and determines when the high power RF electronics is enabled. If the RFID reader is in an over-heated condition, it can be turned OFF and during this period any requests received on an interface to the RFID reader to perform a read of tag(s) are not processed.

Thermal management within mobile RFID readers through the application of temperature governed variable non-emissive intervals

Methods, systems and apparatuses for RFID readers forming a reader network are described. In an aspect of the present invention, a plurality of RFID readers are configured to interrogate tags. Furthermore, the readers are configured to communicate with one another by transferring a token, represented by a signal. Possession of the token enables the reader to access a RF communications medium. Readers can be arranged in a ring configuration, and interconnected via wired links. A secondary token may circulate in the ring in addition to the primary token, to ensure redundancy in the system. A reader waits for a predetermined time interval before accessing the RF communications medium.

Token passing protocol for RFID systems

A system and method is provided for locating objects using RFID tags. The system and method uses an RFID reader and a distance calculator to efficiently and accurately determine the location of objects that include an RFID tag. The RFID reader transmits a plurality of signals to the RFID tag, with the plurality of signals having different fundamental frequencies. In response, the RFID tag backscatter modulates the plurality of transmitted signals to create a plurality of backscatter modulated signals. The RFID reader receives and demodulates the plurality of backscatter modulated signals. The distance calculator determines the phase of the plurality of backscatter modulated signals and determines a rate of change of the phase in the backscatter modulated signals with respect to the rate of change in the fundamental frequency of the transmitted signals and uses this information to calculate the distance to the RFID tag.

Object location system and method using RFID

A multi-resolution object location system and method for locating objects is provided. The multi-resolution system and method uses a long-range object locator together with a more precise RFID locator to efficiently and accurately determine the location of objects that include an RFID tag. The long-range object locator has a relatively longer range and can cover a relatively large area to determine the general location of the object within the large area. The RFID locator has a relatively shorter range, but is able to locate the object more precisely. The object location system uses the long-range locator to first determine the general location of the object, and then the RFID locator is used to determine a more accurate location of the object. Thus, the multi-resolution object location system is able to provide both a long range location of objects over a large area and a precise location of objects.

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New Market, MD, United States of America

Martin J Strzelczyk