| 摘要 |
PROBLEM TO BE SOLVED: To provide a planar antenna which can vary its radiation directional pattern without changing its direction to freely perform communication with its opposite parties in various directions. SOLUTION: This planar antenna 10 consists of a conductive bottom board 13 which is grounded, a slenderλ/2 antenna feeding element 11 which is placed within a virtual plane set opposite to the surface of the board 13 with a prescribed distance and in parallel to the said surface and is fixed to the board 13 by an insulated spacer 14, and the 1st and 2ndλ/2 antenna parasitic feeding elements 15a and 15b having substantially the same shape as the element 11 and placed at the right and left sides of the element 11 which can be switched between the 1st and 2nd positions having small and large distances from the element 11 respectively. When both elements 15a and 15b are fixed at the 1st position, the radiation directional pattern of the antenna 10 is large in the right and left directions shifted from its front. Meanwhile, the said pattern of the antenna 10 is large in its front direction when the elements 15a and 15b are fixed at the 2nd position. Thus, the position of the antenna 10 can be varied as necessary.
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