| 摘要 |
PROBLEM TO BE SOLVED: To provide a small antenna device, which can receive radio waves from plural satellites which are very close with good sensitivity and can obtain the antenna gain of a practical level. SOLUTION: Waveguides 140a and 140b are arranged in response to the respective wave collection positions of radio waves which are transmitted from two satellites and are collected by reflecting mirrors. Dielectric bars 142a and 142b are installed on the respective radio wave incident sides of the waveguides 140a and 140b. Even if the inter-center distance between the waveguides 140a and 140b is set to an optimum value corresponding to the interval of the two satellites, based on the existence of the dielectric bars 142a and 142b and the respective diameters of the waveguides 140a and 140b are formed to be small in degree such that they are not overlapped, the directivity of a primary radiator 14 can be optimized. Consequently, spillover does not occur, and the drop of an antenna gain and the drop of a satellite radio wave reception C/N ratio owing to the increase of reception noise do not occur.
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