Dielectric filter
First Claim
1. A filter (1) comprisinga 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, andan 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.
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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.
75 Citations
10 Claims
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1. 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.
Specification