PURPOSE: To suppress the fluctuation of an impedance or the deterioration of a voltage constant wave ratio(VSWR) when snow is deposited on the antenna main body or an element by covering and molding the periphery of the main body of the linear antenna for a medium wave and short wave or the element of Yagi antenna for an ultrashort wave with a dielectric at a high dielectric rate.
CONSTITUTION: A dielectric filled snow proof type antenna 5 is obtained by covering and molding the periphery of a linear antenna main body 2 with a dielectric 6 at the high dielectric rage. As a result, the dielectric filled snow proof type antenna 5 maintains a constant distance between the antenna main body 2 and the snow deposited in the external periphery of the dielectric 6, and a high dielectric layer is held. The material of the dielectric 6 is synthetically judged and selected based on dielectric strength, a dielectric loss, a high frequency voltage impressed on the snow proof type antenna 5, etc. Thus the antenna has an extremely simple constitution and mechanical strength, it can withstand long-time use, and the fluctuation of the impedance characteristic at the time of snow deposit and the deterioration of the VSWR can drastically be improved.
NATSUBORI HIDEKI
ONO ISAO
NASU YOSHIHIKO
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