| 摘要 |
PURPOSE:To obtain a high radiation efficiency by implementing feeding to a 1/2 wavelength radiation element using a helical radiation element through electromagnetic coupling from a plane resonance circuit wound in spiral having an electric length of 1/4 wavelength. CONSTITUTION:A 1/4 wavelength spiral element 13 is arranged so that a plane of winding in spiral is perpendicular in the lengthwise direction of a 1/2 wavelength radiation element 11. The face of the element 13 is in parallel with a projecting face of the element 11. High frequency power impressed to the element 13 is resonated by the element 13 and coupled with the element 11 at a proper interval through electromagnetic coupling. Then, the dual resonance impedance characteristic of the elements 13, 11 when viewing from the feeding point is adjusted by adjusting the positional relation and the distance between the elements 13 and 11. Thus, the height of the element 13 is decreased, the resonance frequency band of the element 11 is wide and the deterioration in the radiation characteristic in the case of access of a human body to the antenna is decreased. |
