| 摘要 |
PURPOSE:To obtain the small sized, high gain and 2-frequency resonance type torus microstrip antenna by forming a couple of deformation parts with a prescribed area at a prescribed angular interval with a feeding pint to an outer circumferential edge of an inner wall short-circuit torus radiation element. CONSTITUTION:A couple of notches 36c, 36d are engraved at a circumferential edge of a circular radiation element 33 at an angular interval of 180 deg.. The diameter of the radiation element 33 passing through the notches 36c, 36d has an angular interval of 45 deg. counter clockwise with respect to a single feeding point 34. An area DELTAS/2 of the notches 26c, 36d is set by the relation of DELTAS/Sr>1/x(beta).Q0, where Sr is an area of the original torus radiation element, Q0 is a no load Q of the antenna, and x(beta) is a specific value being a function of a ring ratio beta. The radiation element 33 is excited in two modes orthogonal to each other in a direction of a diameter passing through the feeding point 34 and a direction at an angle of 45 deg. thereto, resonated at two frequencies corresponding to the mode and a linearly polarized wave radiates therefrom. |
