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US 5,349,315 AGranted
Dielectric filter
AssigneeLK-Products Oy
InventorJouni Ala-Kojola
Life of this patent
Estimating the term…
Abstract
A ceramic filter can be made small in size by forming one or more strip-line resonators (5) on a side surface (4) of the ceramic resonator, the side surface additionally having contact and coupling electrodes which can be formed using the same mask as for the strip-line resonators. The strip-line resonators (5) produce zeros in the transfer function of the filter and thereby increase the attenuation at a desired frequency, e.g. the image frequency.
Claims10
A filter (1) comprising
- a body of dielectric material having upper and lower surfaces, two side surfaces, two end surfaces, and a hole (3) extending from said upper surface (2) towards said lower surface,
- an electrically conductive layer (6) covering major portions of the lower surface, one side face, both end faces and the surface of said hole thereby forming a transmission line resonator, and
- an electrically conductive strip (5) disposed on a portion of the other side surface (4) forming a strip-line resonator, said transmission line resonator and said strip-line resonator being coupled with each other via an electrical and magnetic field.
A filter according to any of the preceding claims, characterized in that the strip-line resonator (5) produces a pole in the transfer function of the filter (1).
Dependencies are inferred from the claim text.