| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an antenna apparatus which has a wide detection range with simple construction and can reduce false detection due to grating. Ž<P>SOLUTION: Four unit antennas composing an antenna body 11 used for transmission/reception are grouped into two groups of two, and the both groups are supplied with transmission signals (differential power supply) different in phase from each other at 180°. Thus, by the directivity of a transmission antenna having a null point in a front direction, gain at an area end of a main lobe increases. Also, by forming each unit antenna into a crank shape, an aperture of individual unit antenna used as a reception antenna can be wider along an arrangement direction (azimuth detection direction) despite the fact that an arrangement interval of the unit antenna is narrow, and by giving directivity to the reception antenna as well, reception intensity of an angle region where a side lobe of the transmission antenna exists is decreased. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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