| Patent application number | Description | Published |
|---|
| 20090009292 | RFID INTERROGATOR - Embodiments of the invention relate to the field of RFID interrogators, particularly RFID interrogators that combine low loss with high rates of communication from the interrogator to a tag. We describe a transmitter comprising a resonant circuit and a driver coupled to drive said resonant circuit, wherein said resonant circuit includes a resonance regeneration system such that during amplitude modulation of a resonant signal in said resonant circuit when an amplitude of said resonant signal is reduced energy from said reduction is stored and when said amplitude is increased said stored energy is used to regenerate said resonance signal. | 01-08-2009 |
| 20100097187 | RFID TAGS - We describe RFID tags that incorporate a nonlinear resonator that self-adapts to the driving frequency of a reader. More particularly we describe an RF tag for sending data to a tag reader by modulating energy drawn from an RF field of said tag reader, the tag comprising: an antenna; a resonant circuit coupled to said antenna to resonate at a frequency of said RF field; a local power store to store power extracted from said RF field; a modulation system to modulate one or both of the resonance amplitude and a relative phase of a signal in said resonant circuit with respect to said RF field; and a feedback circuit coupled to said resonant circuit and to said local power store to control one or both of said resonance amplitude and said relative phase to control transients in said resonance amplitude caused by said modulation. | 04-22-2010 |
| 20100102932 | RFID TRANSMITTER - Embodiments of the invention relate to the field of RFID interrogators, particularly RFID interrogators that combine low loss with high rates of communication from the interrogator to a tag. Further embodiments relate to the field of active RFID tags and general radio transmitters. We describe a transmitter comprising a resonant circuit and a driver coupled to drive said resonant circuit, wherein said resonant circuit includes a resonance regeneration system such that during amplitude modulation of a resonant signal in said resonant circuit when an amplitude of said resonant signal is reduced energy from said reduction is stored and when said amplitude is increased said stored energy is used to regenerate said resonance signal. | 04-29-2010 |
| 20100289617 | RFID Reader - Embodiments of the invention relate to the field of RFED (radio frequency identification). Some particularly preferred embodiments relate to a high-Q, so-called “full duplex” (FDX) RFID Reader. An RFID tag reader, the reader comprising: an electromagnetic (em) field generator for generating an electromagnetic (em) field for modulation by said tag, said modulation comprising modulated load of said em field by said tag; a detector system responsive to fluctuations in strength of said em field at said reader; a negative feedback system responsive to said detector system to provide a control signal for said em field generator for controlling said em field generator to reduce said detected fluctuations; and a demodulator responsive to said control of said em field to demodulate said em field modulation by said tag. | 11-18-2010 |
| 20100328030 | RFID PET DOOR - An RFID reader for use in a pet door to control access for a pet bearing an RFID tag or implant. The RFID reader incorporates and is operable in two modes, a learn mode and a normal mode. In learn mode, the reader stores the ID code of an RFID transponder in the vicinity of the reader and also derives additional reader information corresponding to the RFID transponder. In normal mode, the reader compares the ID codes stored in memory to the RFID signal returned from an RFID transponder in the vicinity of said the reader. The RFID reader behavior is at least in part determined by the additional reader information corresponding to said ID codes stored in memory. We also describe a confidence threshold for acceptance of an ID code in learn mode and normal mode. The confidence threshold in normal mode may be less than in learn mode. | 12-30-2010 |
