Microchip Technology Inc.

Checkpoint Systems, Inc.

Youbok Lee

Lee Furey

Roger D St Amand

William F Gallagher, Iii

Shinichiro Inui

Samuel E Alexander

Ronald Salesky

Riccardo Benedetti

Sam E Alexander

Ron Salesky

Arbitration of multiple transponders, such as RFID tags, occurs in an interrogation field. The arbitration process is custom-tailored for individual applications, under software control, by the transponder reader or tag reader. Different wake-up slots are calculated for each tag during successive transmission cycles based upon the tag ID and the transmission cycle number. The tag reader may also send a special command to a tag to read its data and cause the tag to become decoupled from the environment. The tags may be selectively placed in either a tag-talk-first mode or a reader-talk-first mode. Furthermore, the tag reader may send a special fast read command to the tag which includes a read request and at least one parameter of the read request.

Anticollision protocol with fast read request and additional schemes for reading multiple transponders in an RFID system

Arbitration of multiple transponders, such as RFID tags, occurs in an interrogation field. The arbitration process is custom-tailored for individual applications, under software control, by the transponder reader or tag reader. Different wake-up slots are calculated for each tag during successive transmission cycles based upon the tag ID and the transmission cycle number. The tag reader may send a special fast read command to the tag which includes a read request and communications control parameters including the number of time slots for transponder communications, the number of transmissions that an individual transponder is allowed to issue, and the data rate at which the reader communicates to the transponder. The tag reader may also send a special command to a tag to read its data and cause the tag to become decoupled from the environment. Additional schemes are provided to halve the number of active tags in each transmission cycle and to selectively inactivate designated groupings of tag, thereby improving discrimination of the tags in the interrogation field. The tags may be selectively placed in either a tag-talk-first mode or a reader-talk-first mode.

A radio frequency identification (RFID) tag device having a pulse position modulation (PPM) decoder circuit which calculates a relative frequency relationship between an internal clock-oscillator of the RFID tag device and an external PPM source such as a RFID tag reader, and then synchronizes the RFID tag device PPM decoder circuit to the required precision for reliable PPM symbol decoding. The PPM decoder is synchronized by measuring the &ldquo;counts per pulse&rdquo; (CPP) from a calibration cycle having a plurality of pulses in a single symbol frame.

Method, system and apparatus for initiating and maintaining synchronization of a pulse position modulation (PPM) decoder with a received PPM signal

A radio frequency identification (RFID) tag on a single layer substrate comprises a semiconductor integrated circuit RFID tag device and antenna circuit. A connection jumper may be used to bridge over the antenna circuit coil turns. The RFID tag device is located on the same side as an inductor coil and capacitor which forms a parallel resonant antenna circuit. The inductor coil has an inner end and an outer end. The inner or outer end may be connected directly to the RFID tag device and the outer or inner end be may connected to the RFID tag device with a jumper over the inductor coil turns, or the RFID tag device may bridge the inductor coil turns when being connected to both the inner and outer ends. An encapsulation (glop top) may be used to seal the RFID tag device and jumper, and an insulated coating may be used to cover the entire surface of the substrate to create an inexpensive &ldquo;chip-on-tag.&rdquo; The encapsulation may be epoxy, plastic or any protective material known to one of ordinary skill in the art of electronic circuit encapsulation. The insulated coating may be of any type suitable for the application of use of the RFID tag.

Radio frequency identification tag on a single layer substrate

A radio frequency identification tag having a step-tunable inductor for tuning a parallel resonant antenna circuit of the radio frequency identification tag to a desired frequency. The step-tunable inductor comprises a plurality of branches in which each branch is adapted for adjusting the step-tunable inductor to a desired inductance value for resonating the parallel antenna circuit to a carrier frequency of a tag interrogator/reader.

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Chandler, AZ, United States of America

Youbok Lee