| 摘要 |
An improved transceiver antenna is designed for mounting on vehicles where, for aerodynamic reasons, vertical orientation is undesirable. It is an object of the present invention to provide a high-gain antenna which, even when mounted at a declination of up to 40 DEG from the vertical, maintains the most smoothly curved possible antenna characteristic. This is achieved by winding four serially connected coils (SP1-SP4) on a rod (12) of dielectric material, with the third coil reverse-wound with respect to the second, with a radiating element (13) connected to the free end of the fourth coil, the lengths of the coils and radiating element being selected to be, respectively, 1/4, 1/4, 1/8, 1/8, and 3/8 of the median wavelength. Upon mounting at an angle of 40 DEG to the vertical, this antenna has an optimal antenna characteristic curve. The antenna is particularly well adapted for use in the frequency band 450 to 470 MHz, which in Germany is assigned by the German Federal Postal Administration to Network C.
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