| 摘要 |
<p>PROBLEM TO BE SOLVED: To maintain the angel in which magnetic fields generated from respective antennas cross at high precision as well as to generate rotation magnetic fields only in a vehicular compartment. SOLUTION: An antenna case 15 is installed in a console box 26 provided between a driver's seat 23 and a front passenger seat 25 in a vehicular compartment 22. A first and second magnetic filed generating parts and a request signal output circuit for driving respective magnetic field generating parts are housed in the antenna case 15. Respective magnetic field generating parts are housed in the antenna case 15 so that the magnetic fields cross to each other and so that the phase of respective magnetic fields have the phase difference of 90 deg.. Rotation magnetic fields by the first and second magnetic fields are generated only in the range shown by a broken line, namely, in the vehicular compartment which covers the driver's seat and the front passenger seat.</p> |
