US 6,583,764 B2 · Loop antenna device

Abstract

To provide a loop antenna device which inhibits the unnecessary radiation of the electric wave and which can increase the sending speed of data placed on the electric wave. The first loop antenna 14 includes the coil L11 and the resonant capacitor C1 and constitutes a series resonant circuit in which the oscillator is connected in series to the coil L11 and the resonant capacitor C1. The second loop antenna 15 includes the coil L2 and the resonant capacitor C2 which are connected each other in parallel and constitutes a parallel resonant circuit. The second loop antenna 15 is magnetically connected to the first loop antenna 14 via the link coil L12. The switching elements 14, 15 are connected to the first and second loop antennas 14, 15 and the damping is performed to the resonant circuits of the antennas 14, 15 when the switching elements 18, 19 become OFF condition by the control signal from the controller 9.

Claims14

Dependent claims

A loop antenna device comprising:

a first loop antenna constituting a resonant circuit that includes a coil and a resonant capacitor and that resonates based on a high frequency signal of a resonant frequency intermittently outputted from an oscillation means;
a second loop antenna constituting a resonant circuit that includes a coil and a resonant capacitor and that resonates by an inductive electromotive force led by a mutual induction via a link coil when the first loop antenna resonates;
and
damping means for compulsorily eliminating a discharge phenomenon of the resonant capacitor when radiation of an electric wave is completed and connected to at least one of the first loop antenna and the second loop antenna.

1 more element

A loop antenna device comprising:

a first loop antenna constituting a resonant circuit that includes a coil and a resonant capacitor and that resonates based on a high frequency signal of a resonant frequency intermittently outputted from an oscillation means;
a second loop antenna constituting a resonant circuit that includes a coil and a resonant capacitor and that resonates by an inductive electromotive force led by a mutual induction via a link coil when the first antenna resonates;
and
damping means connected to the second loop antenna;
wherein a connecting condition of the damping means is changed in response to a timing of a high frequency signal outputted from the oscillation means which is connected to the first loop antenna, and the damping means causes a connected condition of the resonant circuit of the second loop antenna when the high frequency signal is in an output condition, and the damping means compulsorily eliminates a discharge phenomenon of the resonant capacitor when the high frequency signal is in a non-output condition.

2 more elements

Dependencies are inferred from the claim text.

Loop antenna device

Life of this patent

Loop antenna device

Life of this patent

Abstract

Claims14