Batteryless, portable, frequency divider useful as a transponder of electromagnetic radiation
First Claim
1. A frequency divider, comprisinga first circuit that is resonant at a first frequency for receiving electromagnetic radiation at the first frequency;
- a second circuit that is resonant at a second frequency for transmitting electromagnetic energy at the second frequency; and
a semiconductor switching device having gain coupling the first and second circuits for causing the second circuit to transmit electromagnetic radiation at the second frequency solely in response to unrectified energy at the first frequency provided in the first circuit upon receipt of electromagnetic radiation at the first frequency.
2 Assignments
0 Petitions
Accused Products
Abstract
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.
73 Citations
17 Claims
-
1. A frequency divider, comprising
a first circuit that is resonant at a first frequency for receiving electromagnetic radiation at the first frequency; -
a second circuit that is resonant at a second frequency for transmitting electromagnetic energy at the second frequency; and a semiconductor switching device having gain coupling the first and second circuits for causing the second circuit to transmit electromagnetic radiation at the second frequency solely in response to unrectified energy at the first frequency provided in the first circuit upon receipt of electromagnetic radiation at the first frequency.
-
-
2. A frequency divider, comprising
receiving electromagnetic radiation at the first frequency; -
a second circuit that is resonant at a second frequency that is less than the first frequency for transmitting electromagnetic energy at the second frequency; and a semiconductor switching device having gain coupling the first and second circuits for causing the second circuit to transmit electromagnetic radiation at the second frequency solely in response to unrectified energy at the first frequency provided in the first circuit upon receipt of electromagnetic radiation at the first frequency; wherein the semiconductor switching device is a bipolar transistor selected from a group consisting of npn transistors and pnp transistors. - View Dependent Claims (5, 6, 7, 8, 14, 15, 16)
-
-
3. A frequency divider, comprising
a first circuit that is resonant at a first frequency for receiving electromagnetic radiation at the first frequency; -
a second circuit that is resonant at a second frequency that is less than the frequency for transmitting electromagnetic energy at the second frequency; and a semiconductor switching device having gain coupling the first and second circuits for causing the second circuit to transmit electromagnetic radiation at the second frequency solely in response to unrectified energy at the first frequency provided in the first circuit upon receipt of electromagnetic radiation at the first frequency; wherein the semiconductor switching device is a bipolar transistor selected from a group consisting of programmable unijunction transistors and SCRs. - View Dependent Claims (9)
-
-
4. A frequency divider, comprising
a first circuit that is resonant at a first frequency for receiving electromagnetic radiation at the first frequency; -
a second circuit that is resonant at a second frequency that is less than the first frequency for transmitting electromagnetic energy at the second frequency; and a semiconductor switching device having gain coupling the first and second circuits for causing the second circuit to transmit electromagnetic radiation at the second frequency solely in response to unrectified energy at the first frequency provided in the first circuit upon receipt of electromagnetic radiation at the first frequency; wherein the semiconductor switching device is a field effect transistor. - View Dependent Claims (10, 11, 12, 13)
-
-
17. A frequency divider, comprising
a first circuit that is resonant at a first frequency for receiving electromagnetic radiation at the first frequency; -
a second circuit that is resonant at a second frequency that is less than the first frequency for transmitting electromagnetic energy at the second frequency; and a semiconductor switching device having gain coupling the first and second circuits for causing the second circuit to transmit electromagnetic radiation at the second frequency solely in response to unrectified energy at the first frequency provided in the first circuit upon receipt of electromagnetic radiation at the first frequency; wherein the frequency divider is encased within a card-shaped container for use as an electronic tag in a presence detection system.
-
Specification