| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a tunable filter that is capable of shifting a center frequency with ease while maintaining a bandwidth constant. <P>SOLUTION: A tunable filter 1 includes: a rectangular waveguide 2 that is divided into two parts at the center of an H plane; a metal plate 3 that is sandwiched between the two parts of the rectangular waveguide 2 and resonates at a predetermined frequency; and a dielectric plate 4 that is arranged below the metal plate 3 and has two different width dimensions. The dielectric plate 4 is formed so that its width dimension is decreased at each position opposing a part, in which a metal of the ladder-like metal plate 3 exists, and is increased at each position opposing a part, in which the metal of the metal plate 3 does not exists. Also, the dielectric plate 4 is supported at both ends of the rectangular waveguide 2 by support rods 5 extendingly provided on both sides and is constructed so as to be rotatable inside the rectangular waveguide 2. With this construction, it becomes possible to achieve a coupling coefficient with which a bandwidth is maintained constant even when a frequency is shifted by changing an angle of the dielectric plate 4. <P>COPYRIGHT: (C)2013,JPO&INPIT |
