| 摘要 |
PURPOSE:To prevent the direct coupling between image lines and improve the isolation of the device by a method wherein an element is loaded between image lines which were arranged facing each other on a grounding conductor, and the surface, excluding the opposed surface of the lines surrounding the element, is covered by a conductor which is conductive to an earthing. CONSTITUTION:In a transmitting type diode switch, for example, the surface other than that which is opposed by the image lines 2a and 2b, among the surfaces surrounding a diode 4 and a part of strip conductors 3a and 3b, is covered by a metal 10 of prescribed shape which is conducting to an earthing conductor 1. The measurements L1 and L2 of the aperture 11 to be provided by the earthing conductor 1 and the metal 10 are established by selecting the shape with which the waveguide mode electromagnetic field for a signal can be cut off. Accordingly, the direct coupling due to the propagation mode electromagnetic field between the image lines 2a and 2b can be prevented, and isolation characteristics can be improved. Also, such a shield structure as above can be transformed into different shapes, and can be used for various microwave devices such as a transistor amplifier and the like. |
