Resources Contact Us Home
Browse by: INVENTOR PATENT HOLDER PATENT NUMBER DATE
 
 
Electronic article surveillance tag and method for implementing same










Image Number 4 for United States Patent #5030940.

In a method for enhancing the performance of tags for use in an electronic article surveillance system of the type comprising a transmitter-receiver arrangement disposed aside an area to be controlled for transmitting a first high-frequency signal into the area, a transmitter disposed aside the area and generating a second frequency signal of substantially lower frequency than the first frequency for establishing in the area an electrostatic field, a tag for attachment to an article to be subject to surveillance, the tag being responsive to the incidence thereon of energy of both the first and second frequencies to transmit a composite thereof and receiver apparatus disposed aside the area for receipt and detection of such composite signal and for generation of an output signal indicative of such detection, the method involving the steps of: configuring the tag with an antenna for receiving the first and second transmitted signals and for transmitting the composite signal; and a nonlinear circuit for connection electrically with the antenna and responsive to energy derived from the second transmitted signal received by the antenna to exhibit electrical reactance change with change of voltage of the energy; and applying an electrical bias of steady-state nature to the tag dependently on consideration of characteristics of the nonlinear circuit to enhance the electrical reactance change thereof responsively to the energy derived form the second transmitted signal received by the antenna. The considered characteristics of the nonlinear circuit are selected to be a dC/dV slope factor, a 1/c.sup.2 factor and a DC-impedance factor. The nonlinear circuit is selected to be a diode.








 
 
  Recently Added Patents
Moving structure and micro-mirror device using the same
Module-code verification layer to automatically validate user input
Toy
Data storage apparatus, memory control apparatus and method for controlling flash memories
Process for preparing higher hydridosilanes
Mobile communication terminal provided with handsfree function and controlling method thereof
Surround sound effects provided by cell phones
  Randomly Featured Patents
Apparatus for applying flock to a substrate
Container for blood
Compound spark-ignition and diesel engine
Graphical tool for defining a set of ranges
Portable framing gallery
Methods and apparatus for determining minimum cyclic prefix durations
Steering control apparatus for use in endless track type tractors and control valve for use therewith
Polyurethanes for articles for medical usage
Flue seal
Gear transmission for printer die in cigarette making machine