| 摘要 |
PROBLEM TO BE SOLVED: To simplify the structure of an antenna and to improve the directivity of the antenna. SOLUTION: An inner antenna element 14 has a perturbation pattern and is used for a circularly polarized wave. An outer antenna element 16 is used for a linearly polarized wave. A feeding point 20 is provided to the inner antenna element 14. The outer antenna element 16 is energized from the inner antenna element 14 through electromagnetic coupling. The linearly polarized wave and the circularly polarized wave can be received by a few feeding points. Furthermore, the outer antenna element 16 is grounded at an end opposite to and opening 36 to receive the inner antenna element 14. Thus, the outer antenna element 16 is made small in size and a current induced in the outer antenna element 16 can be reduced at the resonance frequency of the inner antenna element 14 to enhance the antenna directivity. |
