| 摘要 |
PURPOSE:To obtain an antenna system with excellent vibration-proof by arranging a loop antenna supported fixedly in a case with a packing member closely to the peripheral of the car body of an automobile along its lengthwise direction so as to detect effectively a current induced in the car body due to a broadcast wave. CONSTITUTION:An opening 40a from which a lengthwise side of a loop antenna 42 is exposed is provided to the case 40 and a part of the loop antenna 42 exposed from the case 40 made of a conductor is arranged closely and oppositely to the car body peripheral. Thus, the magnetic flux induced from a high frequency surface current flowing to the peripheral of the car body is acquired surely by the loop antenna 42 in the case 40 and an external electromagnetic wave is shielded surely by the case 40, then the current induced on the car body is detected by a high frequency pickup 38 with high sensitivity. Further, a low dielectric constant dielectric substance such as polyester, epoxy resin or silicone resin is impregnated or formed by a forming method into the air gap between the case 40 and the loop antenna 42 to support incorporatedly the loop antenna 42. |
