| 摘要 |
PURPOSE:To attain miniaturization of the titled device and to improve the performance by arranging closely a high frequency pickup to a ridge of an engine hood or trunk lid of an automobile along the lengthwise direction and detecting a high frequency surface current flowing concentratedly to the ridge of the engine hood or trunk lid, induced to a car body by a broadcast wave. CONSTITUTION:A loop antenna 46 is arranged within 4.5cm when an FM broad cast wave of 80MHz is received from the ridge of the trunk lid 34 and the surface current flowing concentratedly to the ridge of the trunk lid 34 is caught surely with high efficiency by the loop antenna 46. Since the surface current of the car body flows along the ridge, the loop antenna 46 is arranged so that the lengthwise direction is along the circumferential of the trunk lid 34. Thus, only the magnetic flux induced by the high frequency surface current flowing to the ridge of the trunk lid 34 is caught at the inside of a case 48 and external magnetic flux is shielded surely by the case 48. |
