| 摘要 |
PURPOSE:To obtain a re-entrant cylindrical resonator by which a desirable degree of coupling can be set freely, by providing a sectionally-flat center conductor which is longish in the direction connceting the center of a cavity to the coupling part. CONSTITUTION:Center conductor 15 with a rectangular section has longer side L in the direction connecting center line 3 of cavity 2 to antenna 12 and longer side W perpendicular to it. Intervals between opposite surfce 12A of antenna 12 and coupling window 14, and center conductor 15 decreases as the size of longer side L increases, and the degrees of coupling with coupling window 14 and antenna 12 increase. The increase in the degree of coupling with antenna 12 depends upon an increase in electrostatic capacity between the both, but the degree of coupling with coupling window 14 is caused by the concentration of an electromagnetic field at a part where the interval between conductor 15 and circumferential wall 6 becomes small. Consequently, only the change in the sectional shape of the center cnductor allows the degree of coupling with the outside to increase. As a result, the coupling part of the antenna, etc., can be set easily and a filter of required characteristics can be obtained easily. |
