US 5,684,439 A · Half wave ceramic filter with open circuit at both ends

Abstract

A ceramic filter (100) with a transmission zero is disclosed. The filter (100) includes a block of dielectric material having top (102), bottom (104), and side surfaces (106, 108, 110 and 112), and having two or more metallized through-holes extending from the top to the bottom surfaces (102, 104), defining approximately half wave long resonators. The surfaces are substantially covered with a conductive material defining a metallized layer, with the exception that the top surface (102) is substantially uncoated, and with the additional exception that the bottom surface (104) is also substantially uncoated defining a filter with an open circuit at both ends. The filter (100) also has an input and an output (118, 120) and a mechanism or slot for electrically isolating successive resonators, extending about halfway between the top (102) and bottom surface (104). A filter constructed as detailed above, can have a higher Q value and lower insertion loss.

Claims14

Dependent claims

A half wave length ceramic filter with a transmission zero, comprising:

a filter body comprising a monolithic block of dielectric material and having surfaces including top, bottom, and side surfaces, and having a plurality of metallized through-holes extending from the top to the bottom surfaces defining a plurality of approximately half wavelength resonators, the side surfaces being substantially covered with a conductive material defining a metallized layer, the top surface and the bottom surface are substantially uncoated, defining a filter with an open circuit at opposite ends thereof,
first and second input-output pads comprising a respective area of conductive material on at least one of the side surfaces and substantially immediately surrounded by a corresponding uncoated area of the dielectric material, the first and second input-output pads being capacitively coupled to corresponding ones of the plurality of resonators, and
means for substantially isolating adjacent resonators having at least one metallized slot respectively between each adjacent resonator extending from one of the top and bottom surface, at least about one-quarter wavelength into the filter body.

A half wave ceramic filter with a transmission zero, comprising:

a filter body comprising a monolithic block of dielectric material having surfaces including top, bottom, and side surfaces, and having a plurality of metallized through-holes extending from the top to the bottom surface, defining a plurality of approximately half wavelength resonators, the side surfaces being substantially covered with a conductive material defining a metallized layer, the top surface and the bottom surface are substantially uncoated, thereby defining a filter with an open circuit at opposite ends thereof;
first and second input-output pads comprising a respective area of conductive material on at least one of the side surfaces and substantially immediately surrounded by a corresponding uncoated area of the dielectric material, the first and second input-output pads being capacitively coupled to corresponding ones of the plurality of resonators;
and
the filter body having a plurality of metallized slots respectively between each adjacent resonator and parallel to the resonators and extending from at least one of the top and bottom surface at least one-quarter wavelength into the filter body.

1 more element

Dependencies are inferred from the claim text.

Half wave ceramic filter with open circuit at both ends

Life of this patent

Half wave ceramic filter with open circuit at both ends

Life of this patent

Abstract

Claims14