| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 340572500 | Having tuned resonant circuit | 11 |
| 20080218352 | Radio Frequency Identification - A Radio Frequency Identification (RFID) tag comprises an array of antennas resonant at discrete frequencies. Each antenna can be modified by application of a high power RF signal so as to reduce its resonance or change its resonant frequency, thereby writing information to the array of antennas. | 09-11-2008 |
| 20090002175 | Power Transfer for Transponder Devices - A reader for reading a memory tag comprises a resonant circuit part, a frequency source, a tuning detector and a tuning controller. The resonant circuit part has a resonant frequency. The frequency source is operable to generate a driving signal and is connected to the resonant circuit part to provide inductive coupling to a tag. The tuning detector is responsive to the relative resonant frequencies of the resonant circuit part and a memory tag resonant circuit part of the memory tag to generate a tuning signal. The tuning controller is responsive to the tuning signal to control the resonant frequency of the resonant circuit part. | 01-01-2009 |
| 20090027208 | RFID Tag Containing Two Tuned Circuits - An RFID tag is disclosed adapted to be read by an interrogator including a reader antenna having a carrier frequency. The tag includes a first circuit including a first inductor and a first capacitor, wherein the first circuit is tuned to a frequency above the carrier frequency to compensate for detuning in the presence of a plurality of tags. The RFID tag includes a second circuit including a second inductor and a second capacitor wherein the first and second inductors are arranged to be coupled electromagnetically with a coupling factor less than unity and the second circuit is tuned to increase coupling between the first circuit and the reader antenna. A method of reading an RFID tag in the presence of a plurality of tags is also disclosed. | 01-29-2009 |
| 20090102663 | APPARATUS AND METHOD FOR TUNING A RADIO FREQUENCY ANTENNA - The present invention provides a radio frequency identification tag reader system, that comprises a radio frequency identification tag reader that outputs a drive signal at a predetermined frequency at which a radio frequency tag operates, an antenna that receives the drive signal and radiates an electromagnetic field in response to the drive signal, a tuning circuit disposed between the reader and the antenna so that the drive signal passes through the tuning circuit, wherein the tuning circuit has at least one component that defines a selectable, variable electrical characteristic that selects a resonant frequency of the antenna, a sensor circuit in communication with the antenna so that the sensor circuit detects a response by the antenna to the drive signal and outputs a sensor signal that corresponds to power of an electromagnetic field radiated by the antenna in response to the drive signal, and a processor in communication with the tuning circuit so that the processor controls the selectable component, and wherein the processor receives the sensor signal and sets the variable electrical characteristic in response to the sensor signal. | 04-23-2009 |
| 20090128337 | RFID BASED KEYBOARD - An RFID keyboard comprising a base with a first antenna and; keys with secondary antennas wherein a key is normally in a first position such that the resonant frequency is away from an interrogation frequency and no signal for the key is detected and wherein when the key is depressed, the secondary antenna for the key and the first antenna become adjacent such that the resonant frequency shifts such that information identifying the key is transferred. | 05-21-2009 |
| 20090201156 | WIRELESS IC DEVICE - A wireless IC device includes an electromagnetic coupler module including a wireless IC chip processing transmission and reception signals, and a feeder circuit board. In the wireless IC device, a first coupler defining a feeder circuit arranged on the feeder circuit board is electromagnetically coupled with a first mount of a first radiation plate, and a second coupler is electromagnetically coupled with a second mount of a second radiation plate. The couplers are respectively defined by line electrodes. Input and output terminal electrodes of the wireless IC chip are electrically connected to the line electrodes. The wireless IC chip is operated by the first and second couplers in response to a signal received by first and second radiation plates. A response signal from the wireless IC chip is radiated to the outside from the first and second radiation plates via the first and second couplers. | 08-13-2009 |
| 20090251320 | Resonance Tag - A resonance tag includes a dielectric layer, a first circuit layer, a second circuit layer and a hard pad. The first circuit layer is formed on one surface of the dielectric layer, and the first circuit layer has a first electrode pattern and a coil. A second circuit layer is formed on the other surface of the dielectric layer, and the second circuit layer has a second electrode pattern and a wiring. A hard pad is formed on the second circuit layer and corresponding to the wiring of the second circuit layer, and then an edge of the hard pad is beyond the edge of the wiring. | 10-08-2009 |
| 20090273474 | RADIO IC TAG - [PROBLEM(S)] To provide a wireless IC tag which is readable even in a plurality of countries (destination countries) using different radio frequency bands for reading. | 11-05-2009 |
| 20090278689 | MINIATURE RESONATING MARKER ASSEMBLY - A miniature resonating marker assembly that includes, in one embodiment, a ferromagnetic core, a wire coil disposed around the core, and a capacitor connected to the wire coil adjacent to the magnetic core. The core, coil, and capacitor form a signal element that, when energized, generates a magnetic field at a selected resonant frequency. The magnetic field has a magnetic center point positioned along at least one axis of the signal element. An inert encapsulation member encapsulates the signal element therein and defines a geometric shape of the resonating marker assembly. The geometric shape has a geometric center point substantially coincident with the magnetic center point along at least a first axis of the signal element. The shape and configuration of the assembly also provides for a miniature signal element specifically tuned to resonate at a selected frequency with a high quality factor. | 11-12-2009 |
| 20100019907 | Self Tuning RFID - The antenna of an RFID tag is automatically tuned by controlling both the real and imaginary components impedance “seen” by the antenna. The real component (resistive) is controlled by controlling a tap of a charge pump circuit of the tag. The imaginary (reactive) component is controlled by connecting one or more reactive elements of an antenna tuning circuit to the antenna. The real component is controlled by a first digital control loop that automatically activates successive taps on a charge pump of the RFID tag which effectively controls the resistance seen by the antenna. A second digital control loop controls the connection of the various reactive components. | 01-28-2010 |
| 20100039267 | CIRCUIT AND METHOD FOR POWER-UP OPTIMIZATION OF RFID TRANSPONDER - The present invention relates to a radio-frequency identification tag ( | 02-18-2010 |
