| 摘要 |
A communication terminal that, even when laid on a metallic plate, can maintain good reception sensitivity is provided without any necessity of altering body size or design. A board (125) connected an antenna (107) is disposed within a lower housing (105). The board (125) has a GND surface connected to a radiation element (121). The radiation element (121) is coupled to an auxiliary ground plate (123) approximately orthogonal thereto. The radiation element (121) and auxiliary ground plate (123) both are conductors. The board (125) allows a high frequency current (131) to flow therethrough. When the communication terminal is laid on a metallic plate (141), a mirror image effect causes a high frequency current of opposite phase (133) to flow through the metallic plate (141), so that it cancels the high frequency current (131), thereby reducing the radiation of the antenna (107). It should be noted that since the mirror image effect does not cause components orthogonal to the metallic plate (141) to cancel each other, the radiation element (121) constitutes a dipole antenna symmetrically with respect to the metallic plate (141).
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