Abstract: A multi-coil antenna array constructed with a tuned transformer to null mutual inductance. First and second antenna coil halves are displaced longitudinally on opposite sides of a pathway along which ID tags pass, for example, a chute assembly. The planar coils are displaced at a selected angular orientation and driven with inputs having a 90° phase differential to create an intermediate vertical field with a vertical axis of rotation. Identification data stored in tags attached to animate or inanimate objects passing through the field is interrogated, such as data identifying people, animals, inventory or any other parameters of interest.

Abstract: A tag for use with an individual monitoring system. The tag is worn by an individual being monitored, preferably on the ankle or leg where it can be concealed by the clothing of the individual. The tag is fully self contained and sealed. The circuits of the tag periodically generate an identification signal that includes an identification code. The identification signal modulates a stable RF signal that is transmitted in bursts of data words to a receiver associated with a field monitoring device (FMD) located at the monitoring location. In turn, the FMD may randomly establish communication with a central processing unit (CPU) located at a central monitoring location. Other information is included in the identification code of the tag, such as information indicating that an attempt has been made to remove the tag from the individual. The tag is held in place near the skin of it's wearer by a conductive strap that wraps around the leg or other limb of the individual.

Abstract: A house arrest monitoring system that automatically verifies the presence or absence of prisoners, patients or other personnel who are required to remain at a prescribed location or to report to the prescribed location at a certain time. The system includes an identification tag that is worn by the individual being monitored. This tag transmits an identification signal that includes a unique identifying code, as well as status information that indicates whether the tag has been removed from near the flesh of the individual being monitored. The tag is totally self-contained and includes circuitry to sense when the tag is held near the flesh of the individual, as well as code generating and transmitting circuitry to periodically generate and transmit the identification signal. A field monitoring device (FMD) is included at the prescribed location to receive and process the identification signal, and to communicate with a central processing unit (CPU) located at a remote central monitoring location.

Abstract: A tag for use with an individual monitoring system. The tag is worn by an individual being monitored, preferably on the ankle or leg where it can be concealed by the clothing of the individual. The tag is fully self contained and sealed. The circuits of the tag periodically generate an identification signal that includes an identication code. The identification signal modulates a stable RF signal that is transmitted in bursts of data words to a receiver associated with a field monitoring device (FMD) located at the monitoring location. In turn, the FMD may randomly establish communication with a central processing unit (CPU) located at a central monitoring location. Other information is included in the identification code of the tag, such as information indicating that an attempt has been made to remove the tag from the individual. The tag is held in place near the skin of it's wearer by a conductive strap that wraps around the leg or other limb of the individual.