Abstract: An apparatus, which allows a radio frequency identification (RFID) reader to recover quickly from transient input to its receiving subsystem when transitioning from writing to an RFID transponder to reading its response. In particular, this apparatus is comprised of muting circuits, which both attenuate transients in its receiving subsystem while writing to a transponder, and help the receiving subsystem settle quickly after experiencing such transients.

Abstract: A passive radio frequency identification (RFID) reader is configured to dynamically vary the Q factor of its resonant antenna coil circuit in order to optimize its performance under different conditions. This RFID reader suitably provides optimal performance for both transponder reading and transponder writing operations, rather than being designed for optimal performance for only one operation or the other, or some fixed compromise between them.

Abstract: An apparatus, which allows a radio frequency identification (RFID) reader to recover quickly from transient input to its receiving subsystem when transitioning from writing to an RFID transponder to reading its response. In particular, this apparatus is comprised of muting circuits, which both attenuate transients in its receiving subsystem while writing to a transponder, and help the receiving subsystem settle quickly after experiencing such transients.

Abstract: The electronic identification system provides two-way communications between reader and tags using alternating magnetic fields established by the reader and tag. Communication is accomplished by utilizing either a one-step or a two-step modulation process in which the information to be communicated either modulates an alternating magnetic field directly or modulates a periodic signal which modulates an alternating magnetic field. The coil in the reader that is used to establish an alternating magnetic field is transformer-coupled through capacitors to a push-pull driving circuit consisting of four field-effect transistors connected in a bridge arrangement. The coil, capacitors, and coupling circuitry are maintained in a tuned condition by continually adjusting either the driving frequency, the coil inductance, or the capacitor capacitance during communications.

Abstract: The present invention relates to a dual antenna coil identification system, and more particularly, to an interrogator or reader for inductively coupling to a transponder and thereby extract data from the transponder. The magnetic field required to energize a transponder is generated by currents flowing through two essentially identical but opposite phased antenna coils arranged near the area where tags are to be read.

Abstract: An improved interrogator for an inductively coupled identification system is disclosed. The interrogator provides a multidimensional electromagnetic field through a plurality of coils aligned relative to each other. The coils provide a rotating magnetic field having approximately constant amplitude regardless of orientation with respect to the transponder. An additional coil may be utilized to precess the multidimensional electromagnetic field. The interrogator may further provide an impedance matching network that includes a series drive capacitor to match the impedance of a capacitor in parallel with a coil to a driver load impedance.

Abstract: A method of fabricating, a composition and overmolded components fabricated by the method and with the composition such as an overmolded transponder circuitry for a radio frequency identification device.

Abstract: An improved interrogator for an inductively coupled identification system is disclosed. The interrogator provides a multidimensional electromagnetic field through a plurality of coils aligned relative to each other. The coils provide a rotating magnetic field having approximately constant amplitude regardless of orientation with respect to the transponder. An additional coil may be utilized to precess the multidimensional electromagnetic field. The interrogator may further provide an impedance matching network that includes a series drive capacitor to match the impedance of a capacitor in parallel with a coil to a driver load impedance.

Abstract: A method of fabricating, a composition and overmolded components fabricated by the method and with the composition such as an overmolded transponder circuitry for a radio frequency identification device.

Abstract: A method of fabricating, a composition and overmolded components fabricated by the method and with the composition such as an overmolded transponder circuitry for a radio frequency identification device.

Abstract: An improved interrogator for an inductively coupled identification system is disclosed. The interrogator provides a multidimensional electromagnetic field through a plurality of coils aligned relative to each other. The coils provide a rotating magnetic field having approximately constant amplitude regardless of orientation with respect to the transponder. An additional coil may be utilized to precess the multidimensional electromagnetic field. The interrogator may further provide an impedance matching network that includes a series drive capacitor to match the impedance of a capacitor in parallel with a coil to a driver load impedance.

Abstract: A reader (10) capable of efficiently reading tags (12) of differing protocols in a radio frequency identification system. The tag may be either a full-duplex tag or a half-duplex tag. The reader includes a display (16), a power switch (18) and a read switch (20) for enabling operation of the reader by a user. The reader further includes a coil (60); a driver circuit (32) coupled to the coil; and a signal analyzing circuit (82, 84, 90) coupled to the coil. The signal analyzing circuit analyzes tag identification signals sensed by the coil by detecting an initial data sequence of the tag identification signals and selecting from at least two different protocols the correct protocol of the tag identification signal.