| 摘要 |
<p>PURPOSE: To provide a multiple wave common-use antenna which eliminates the possibility that an antenna element is damaged when the car is washed, reduces the generation of a wind whistle at the time of a high-speed travel, has excellent transmission/ reception characteristics (gain and band) of an MT wave and excellent reception sensitivity of AM and FM waves, and makes possible high-reliability operation. CONSTITUTION: This antenna is equipped with a 1st frequency band antenna element 10 which is formed of a cylindrical conductive pipe and matches radio waves of a high frequency band, a 2nd frequency band antenna 20 which is formed of a flexible thin-diameter conductive rod inserted coaxially into the axis part of the element 10 while insulated and matches radio waves of a low frequency band, a 1st feeding part which is provided at the base end part of the element 10, and a 2nd feeding part which is provided at the base end part of the element 20. When the wavelength of the center frequency of the high frequency band is denoted asλ, the electric length L1 from a ground conductor W to the element 10 is set toλ/4 toλ/2, the electric length L2 of the 2nd element 20 projecting from the upper end part of the element 10 is set to an odd multiple ofλ/4, and the electric length L3 from the upper end part of the element 10 to the 2nd feeding part 80 is set to an integral multiple ofλ/2.</p> |
