| 摘要 |
PURPOSE:To resonate a microstrip antenna which is used for a mobile communication system, etc., in two resonance frequencies, by providing a feeding point on the straight line where perpendicular lines drawn down on both the long axis and the short axis of an elliptical radiation conductor element are equal. CONSTITUTION:In the structure which consists of a radiation conductor element 1, a ground conductor 2 and a dielectric 3, and is coupled with a coaxial line 6 on the reverse side of the conductor 2, an elliptical radiation conductor plate is used for the element 1. A feeding point 4 is provided on the straight line where perpendicular lines drawn down on both the long axis 9 and the short axis 10 of this element 1 become equal, in order to energize the feeding electric field which is coupled with both the intrinsic modes of the long axis 9 and the short axis 10. Also, as far as the feeding point is concerned, the input impedance at the feeding point and the characteristic impedance of the coaxial line 6 are matched and provided on said straight line. As a result, it is possible to obtain the input/output terminal 7 which resonates in frequencies being mutually different. In this regard, the element 1 and the conductor 2 are short-circuited at the intersection point 8 of the long axis 9 and the short axis 10 of the element 1. In this way, it is possible to obtain an antenna which is small-sized, light in weight and low in attitude, and resonates in frequencies being mutually different. |
