| 摘要 |
PROBLEM TO BE SOLVED: To provide an on-vehicle antenna capable of taking a low attitude with a simple configuration without the need for using a thick element width. SOLUTION: The on-vehicle antenna 1 comprises a spiral antenna 2 and a ground plate 3. The spiral antenna 2 is formed by copper wires in spiral so as to function as a radiation element. The a spiral shaped slit 5 the same shape as the spiral antenna 2 is formed to the ground plate 3 at a position direct under the spiral antenna 2, and the spiral antenna 2 is opposed to the slit 5, that is, a space part. Thus, even when a traveling wave travels through the spiral antenna 2, no ground current by the traveling wave is produced. Alternatively, even when the ground current is produced, since it can be suppressed, the cross polarized wave ratio can be enhanced by suppressing production of a standing wave even when the antenna takes the low attitude. COPYRIGHT: (C)2006,JPO&NCIPI
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