04481428 is referenced by 43 patents and cites 35 patents.

A batteryless, portable, frequency divider including a first LC circuit that is resonant at a first frequency for receiving electromagnetic radiation at the first frequency; a second LC circuit that is resonant at a second frequency that is one-half the first frequency; and a transistor coupling the first and second LC circuits for causing the second LC circuit to transmit electromagnetic radiation at the second frequency in response to the first LC circuit detecting electromagnetic radiation at the first frequency. The first and second LC circuits respectively include inductance coils that are positioned orthogonally to one another so as not to be mutually coupled. The frequency divider is operable solely from unrectified energy at the first frequency provided in the first circuit upon receipt of the electromagnetic radiation at the first frequency detected by the first LC circuit. The frequency divider is useful as an electronic tag for attachment to articles for enabling detection thereof when moved through a surveillance zone containing electromagnetic radiation at the first frequency and thereby is useful in shoplifting detection systems.

Title
Batteryless, portable, frequency divider useful as a transponder of electromagnetic radiation
Application Number
6/265149
Publication Number
4481428
Application Date
May 19, 1981
Publication Date
November 6, 1984
Inventor
Lincoln H Charlot Jr
Tampa
FL, US
Agent
Brown & Martin
Assignee
Security Tag Systems
FL, US
IPC
H01J 19/82
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