| 摘要 |
PURPOSE:To attenuate the 3rd harmonic component by selecting the position of a coupling hole of coaxial dielectric resonators to a position where an electric field by the 3rd harmonic component of the fundamental frequency is minimized. CONSTITUTION:Dielectric blocks 1A, 1B are provided respectively with two through-holes 2, 2A, and 2B, 2C and all faces except the upper face of each dielectric block and counter faces of each dielectric block are metallized to constitute a coaxial 1/4 wavelength resonator. Moreover, in the electric field distribution of the resonator, since a coaxial inner conductor is short-circuited at the bottom of the dielectric block and opened at the upper face, the electric field component of the 3rd harmonic of the fundamental frequency is minimized at a position corresponding to 2/3 of the said inner conductor, while the electric field in the fundamental frequency is slightly less than the maximum value. Thus, the filter reducing effectively the 3rd harmonic is constituted by inserting a shielding plate 4 having a coupling hole at the said position to a counter part of the said coaxial dielectric resonators. |
