Lucent Technologies Inc.

Eric Sweetman

R Anthony Shober

Israel Amir

Gregory Alan Wright

You-Sun Wu

Frank P Higgins

A circuit board, for use with a high speed backplane, includes transmitter and receiver with circuitry for correcting for multipath signal errors. A training sequence that is often a pseudo-random signal is transmitted by the transmitter on a first circuit board to a receiver located on a second circuit board. The receiver on the second circuit board includes an analog-to-digital signal converter, an equalizer, and a binary digital-to-analog reconverter for receiving the training sequence. The equalizer preferably comprises a series of connected registers having taps in between, a plurality of individual weighting means attached to each of the taps, and a summing means connected to the weighting means. A training sequence is transmitted from the first circuit board to the receiver on the second circuit board, enabling the receiver to adaptively determine a set of weighting means coefficients for correcting the multipath errors in subsequent signals. Coefficients for the weighting means are then adjusted from the output of the summing means. The method and system described can substantially reduce the cost of backplane fabrication and enhance the performance of the overall system.

Method and system to increase the performance of high-speed backplanes

The present invention provides for an inexpensive RFID Tag design which uses an inexpensive Backscatter Modulator. The modulator is simply a CMOS gate driven by a shift register containing a modulating signal. The CMOS gate is connected to the antenna such that it modulates the reflectivity of the antenna in accordance with the modulating signal. In a second embodiment, the Tag is incorporated into a single CMOS integrated circuit which comprises all of the components, except for the antenna, necessary to implement an inexpensive read-only RFID Tag.

Inexpensive modulated backscatter reflector

In accordance with the present invention, a general antenna system is disclosed suitable for applications in which an RFID Tag passes by an Interrogator. We then disclose a specific antenna design that uses a single planar antenna for transmit and a multi-element planar antenna array for receive. The multi-element planar antenna array is spaced such that each of the planar elements is four inches apart, center-to-center, thus defining a narrow 30&deg; receive beamwidth in the horizontal plane. The vertical receive bandwidth is much greater than 30&deg;, facilitating the Interrogator receiving signals at a variety of elevations. Furthermore, a multi-way microstrip combiner is used to sum the signals received from each of the planar antennas. To block interference from the transmit antenna and to improve receive sensitivity, this multi-way microstrip combiner is shielded using, in one embodiment, copper tape along its edges. In a specific embodiment, a four element receive antenna design is disclosed.

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Princeton, NJ, United States of America

Eric Sweetman