CIRCULARLY POLARIZED ANTENNA

PROBLEM TO BE SOLVED: To provide a circularly polarized antenna arranged in a compact form, which can be manufactured further readily.SOLUTION: A circularly polarized antenna 1 according to an embodiment hereof comprises: an inverted F antenna 20 having an open end arranged on a corner side on one side of two sides of a rectangular-shaped ground conductor plate 10, which are orthogonal to each other; a dipole antenna 30 provided on the other side; and an EM power-supply part 41 of a power-supply part 40 disposed on and opposed to the open end sides of the antennas. The inverted F antenna 20 is connected to the ground conductor plate 10 to be short circuited thereto by a first short-circuit portion 22 and a second short-circuit portion 23 on a side opposite to the open end thereof. The inverted F antenna 20 (λ/4 type) and the dipole antenna 30 (λ/2 type) are disposed on a sheet metal to be orthogonal to each other and supplied with electric power at one point by EM coupling in this way. This consequently makes it possible to manufacture a circularly polarized antenna readily and to generate circularly polarized waves that allow a high gain (about 3 dBc), a high efficiency (a little less than 90%) and a satisfactory angle width to be ensured.SELECTED DRAWING: Figure 1 【課題】より容易に製造可能で小型化された円偏波アンテナを提供する。【解決手段】実施形態の円偏波アンテナ１では、矩形形状の地導体板１０の直交する２辺の一方の辺側に角側を開放端とする逆Ｆアンテナ２０と、他方の辺側にダイポールアンテナ３０を配設し、両開放端側に給電部４０のＥＭ給電部４１を対向配置させる。逆Ｆアンテナ２０の開放端側と反対側は、第１短絡部２２、第２短絡部２３により地導体板１０に短絡接続されている。このように、逆Ｆアンテナ２０（λ／４型）と、ダイポールアンテナ３０（λ／２型）を板金上に直交に配置し、ＥＭ結合による１点給電した結果、容易に製造可能な円偏波アンテナとすることができ、また高利得（約３ｄＢｃ）、高効率（９０％弱）、良好な角度幅、を確保する円偏波を発生させることができた。【選択図】図１