| 摘要 |
PURPOSE: To prevent the occurrence of energy dissipation and temperature rises by clipping a magnetic flux passing to a coupled wheel antenna from a fixed antenna. CONSTITUTION: An excitation and listening assembly 4 which is connected to each fixed antenna 1 through one electric line 41 is set on a vehicle. The assembly 4 generates an output, for example, a signal having a frequency of, for example, 83 kHz selected for transmission. Each fixed antenna 1 is also provided with a capacitor 12 for forming sequential resonance circuits. A wheel antenna 2, on the other hand, has a size which is decided so that the resonance frequency can become 83kHz by taking the stray capacitance 23 at which parallel resonance is obtained into consideration and set on a wheel. Then a magnetic flux passing to the coupled wheel antenna 2 from the fixed antenna 1 is clipped. Therefore, the occurrence of energy dissipation and temperature rises can be prevented. |
