| 摘要 |
PROBLEM TO BE SOLVED: To provide a simple directional antenna, mounted on a portable wireless machine for measuring the arrival direction of a wave and setting the antenna with adequate directivity. SOLUTION: A directional antenna 100, formed into a linear bar shape as a whole, includes a plurality of antenna elements 11, 12, 13, and 14 extended in parallel with the same length with respect to a central line of the bar shaped body, a reflection device 20 made up of plates 21, 22, 23, and 24, extended in parallel with the central line for covering the space of the antenna elements and the central-line side, and switches 41, 42, 43, and 44 for making active by selectively connecting some of antenna elements to a coupling/distributing unit 50 and making the antenna of activated antenna elements with desired directivity as a whole.
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