94results about How to "Improve reading distance" patented technology

A system and method for tracking articles and controlling inventory thereof on a real time basis comprising the use of a tag assembly including a plurality of tags including both active tags and passive tags distinguishable from one another by the provision of a self contained power source in the active tags. One or more readers are disposed within a locale being monitored and are structured to communicate received data transmission from a host controller, for additional administrative processing in terms of determining the existence, location and / or movement of various articles with which the plurality of tags are directly associated. Depending on their category the tags may be activated by either entering an electric field of a predetermined first frequency or by receiving an activation signal from the reader assembly also transmitted at the first predetermined frequency. Communication between the tags and the reader occurs at a second frequency being different from the first frequency.

A battery-assisted radio frequency identification (RFID) tag having a battery-assisted circuit and a filter is provided. The battery-assisted circuit generates a radio frequency signal whose frequency is outside an operating frequency band of the RFID tag to supply additional power to the RFID tag. The filter filters the radio frequency signal output from the battery-assisted circuit before the RFID tag demodulates a reader command, so that a modulation depth of the read command is less affected by multi-carrier. By using the battery-assisted circuit and the filter, the RFID tag has a longer read range and is less affected by multipath fading effects.

Turning now to the drawings, systems and methods for reading RFID transponders utilizing readers in which the Q-factor of the resonant antenna of the reader shifts over the course of the reader's interrogation cycle in response to the detection of data from FDX and HDX RFID transponders in accordance with embodiments of the invention are illustrated. One embodiment having a dynamically adjustable Q-factor, wherein the reader transmits an activation signal configured to activate half duplex and full duplex transponders includes a signal source configured to drive a resonant antenna and a dynamic switching circuit configured to set the Q-factor of the resonant antenna to a first value during the transmission of the activation signal. In addition, the dynamic switching circuit is configured to set the Q-factor of the resonant antenna to a second value below the first value during and / or in response to detection of a data signal from a full duplex transponder, the dynamic switching circuit is also configured to set the Q-factor of the resonant antenna to a third value below the second value when the RFID reader is not transmitting the activation signal, and the resonant antenna is multi-filar and the dynamic switching circuit is configured to control the Q-factor of the multi-filar resonant antenna by controlling the filars that are incorporated into the resonant antenna circuit.