| 摘要 |
<p>Harmonic frequencies of a ceramic filter (1) can be efficiently attenuated by placing in a hole (2; 3) of a first and/or last resonator a conductive rod (7; 7 min ), on which disk-like insulating plates (9, 10, 11, 12; 9 min , 10 min , 11 min , 12 min ) are provided in spaced relationship along the length of the rod. The harmonic filter thus formed is a low pass filter, comprising transverse capacitances formed by the insulating plates and longitudinal inductances formed by the rod portions between the plates. Coupling between the harmonic filter and the resonators of the main filter takes place at the upper end of the rods (7, 7 min ). <IMAGE></p> |
