To reduce the generation of the distortion of the directivity of a GPS antenna apparatus of a GPS car-navigation apparatus, which is caused by its interference with the components present in its periphery generated when disposing it on or in a dashboard.
An electromagnetic-wave absorber 4, formed out of a ferrite, etc., is provided on the rear-surface side of a board 2 made of a conductive material whereon an antenna element 3 comprising patch elements is provided. Then, external electromagnetic waves are prevented by the absorber 4 from being reflected by the metal components present in the periphery of the GPS antenna apparatus, to make it incident on the rear surface of the board 2. Therefore, generation of the faults is prevented, where currents are generated by making the reflection waves incident on the rear surface of the board 2 and the electromagnetic waves caused by the currents are sneak into the front side of the board 2 from its rear surface side by their radiations or diffractions, as to prevent the distortion of the directivity of the GPS antenna apparatus.
FUKUI SHINJI
NODA KAZUNOBU
HAYASHI AKIHIKO
KOIDE SHIRO
NIPPON SOKEN
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