| 摘要 |
PURPOSE:To enable to select the vertical and horizontal polarization characteristics as required, by combining the sleeve having a slot to one pole shape antenna element. CONSTITUTION:The conductive cylindrical sleeve 3 having the slot 2 to be extended axially, the pole shape antenna element 4 free of extension and contraction axially, motor 6 to extend or contract the element 4 in the sleeve 3, and switch-over driving mechanism 9 electrically switch-over-connecting the axial cable 8 as power feed cable to the antenna unit 1 are provided. When the motor 6 is driven and the element 4 is extended, the center conductor of the cable 8 is connected to the element 4 through the tip of the sleeve 3 and the external conductor of the cable 8 is connected to the sleeve 3 to constitute the sleeve antenna having the vertical polarization surface characteristics. When the element 4 is contained in the sleeve, the center conductor of the cable 8 is connected to one end of the slot of the sleeve, and the external conductor is connected to another end of the slot, to constitute the slot antenna having the horizontal polarization characteristics. |
