| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem of a conventional filter device that variations occur in electric resistance in a contact portion depending on fastening situation when a resonant element is screwed, resulting in a low Q value of the resonator configured between the inside of a frame and the resonant element disposed in the inside. <P>SOLUTION: A frame 11 is shaped in such a way that a plated steel plate having plating surfaces on both surfaces of a steel plate is cut by press processing, and the plated surfaces inside a side plate 11d are brazed through a connection member. The resonant element 12 is made of a metallic cylinder, the metallic cylinder having a plated surface is used for at least the circumferential surface of the cylinder and the top surface thereof, and a lower end of the resonant element 12 is brazed to the plated surface inside a filter casing 11 through the connection member. By doing this, even when the frame is configured using a plated steel plate, deterioration of insertion loss can be prevented and the filter device having mass-productivity can be obtained. <P>COPYRIGHT: (C)2009,JPO&INPIT |
