Patent ID: 6208235
Filing Date: 2001-03-27
Classification: G01S,G06K,G08B,H04B

Abstract:
A radio frequency intelligent transponder comprising:an integrated circuit for storing data;an inductor including a first coil electrically connected to a second coil;a resonant capacitor electrically connected to the integrated circuit and at least one of the first and second coils, the resonant capacitor and the at least one connected coil having a first predetermined resonant frequency; anda switch having a first position and a second position for selectively allowing a current to flow through the second coil, wherein when the switch is in the first position, exposure of the transponder to an external field at or near the first resonant frequency induces a voltage on the inductor and causes a first current to flow through the inductor in a first direction, thereby generating a near field and when the switch is in the second position, exposure of the transponder to an external field at or near the first resonant frequency induces a voltage on the inductor and causes a first current to flow through the first coil in a first direction, thereby generating a first near field and a second current to flow through the second coil in a second, opposite direction, thereby generating a second near field, wherein a sum of the first and second near fields approaches zero.