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US 5,319,328 AGranted
Dielectric filter
AssigneeLK-Products Oy
InventorAimo Turunen
Life of this patent
Estimating the term…
Abstract
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'), on which disk-like insulating plates (9, 10, 11, 12; 9', 10', 11', 12') 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').
Claims10
A filter comprising:
- a body of dielectric material having upper and lower surfaces, the body having portions coated with a conductive material, and at least two holes extending from the upper surface towards the lower surface and being coated with the conductive material, whereby a respective transmission line resonator is formed for each hole;
- and
- means in at least one of the resonator holes for filtering frequencies higher than the desired operating frequency of the filter, the means for filtering frequencies higher than the desired operating frequency of the filter comprising an elongate conductive material, and a plurality of insulating disk-like members provided in space-apart relationship along the length of the elongate member.
Dependencies are inferred from the claim text.