LOOP ANTENNA DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a loop antenna device which can suppress unwanted emission and improve communication speed of data carried by a radio wave. SOLUTION: A first loop antenna 14 is provided with a coil L11 and a resonance capacitance C1, and an oscillator 10 is connected in series with the components L11, C1, thereby constituting a series resonance circuit. A second loop antenna 15 is provided with a coil 12 and a resonance capacitance C2, and the components L2, C2 are connected in parallel, thereby constituting a parallel resonance circuit. The second loop antenna 15 is connected magnetically with the first loop antenna 15 via a link coil L12. Switching elements 18 and 19 are connected with the first and second loop antennas 14 and 15, respectively. When the switching elements 18, 19 are turned off by a control signal from a controller 9, the resonance circuits of respective antennas 14, 15 are subjected to damping.