Wave transmission lines and networks – Coupling networks – Wave filters including long line elements
Reexamination Certificate
1999-09-27
2001-11-06
Pascal, Robert (Department: 2817)
Wave transmission lines and networks
Coupling networks
Wave filters including long line elements
C333S204000, C333S222000
Reexamination Certificate
active
06313720
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a dielectric resonator arrangement, and more particularly, to a dielectric resonator device constructed by forming a plurality of resonator electrodes on a dielectric substrate or dielectric block.
2. Description of Related Art
Conventionally, there have been employed a multi-stage dielectric resonator device constituted by forming a plurality of resonance electrodes (inner electrodes) within a dielectric block, and a ground electrode over the outer face of said dielectric block, and a strip-line type multi-stage resonator device having a plurality of resonance electrodes formed on the surface of a dielectric substrate, and a ground electrode formed on a confronting surface of said dielectric substrate, for example, as a band-pass filter, etc. in a microwave band region.
In the dielectric resonator device having a plurality of inner electrodes formed within the dielectric block, coupling bores or holes are formed to achieve coupling among respective resonators for setting of the amount of coupling by the size of such coupling bores. However, in this type of the resonator device in which the coupling bores are to be provided, not only is the productivity low in the manufacture of the device, but it has been difficult to adjust the coupling amount properly.
Therefore, it has been considered to control resonator characteristics by adjusting the range over which the inner electrodes are formed as shown in FIG.
4
(A), which is a top plan view of a conventional dielectric resonator device, and FIG.
4
(B) representing a side sectional view taken along the line IV(B)—IV(B) in FIG.
4
(A).
In FIGS.
4
(A) and
4
(B), the known resonator device, for example, in the form of a symmetrical 4 stage band-pass filter, includes a dielectric block
1
′ with four through-holes formed therein, and inner electrodes
2
a
′,
2
b
′,
2
c
′ and
2
d
′ formed on the inner peripheral surfaces of said through-holes. The dielectric resonator device as referred to above may be represented by an equivalent circuit as shown in
FIG. 5
, in which R
1
, R
2
, R
3
and R
4
denote the resonators formed by the inner electrodes
2
a
′,
2
b
′,
2
c
′ and
2
d
′ as shown in FIGS.
4
(A) and
4
(B), with symbols K
1
and K
2
representing the coupling amounts between the respective neighboring resonators. In the dielectric resonator device having the construction as illustrated in FIGS.
4
(A) and
4
(B), for example, the resonance frequency of the resonator R
2
is determined by a length L
2
′ of the inner electrode
2
b
′ at a second stage, while the coupling amount K
2
is determined by a length S
2
′ of a region in which the inner electrode is not formed, and an interval P
2
′ between the inner electrodes
2
b
′-
2
c′.
When a filter is to be designed in which the relations represented by f
1
>f
2
and K
1
>K
2
are true on the assumption that the dielectric resonator device shown in FIGS.
4
(A) and
4
(B) is constructed as the symmetrical
4
stage band-pass filter, and the resonance frequencies of the resonators R
1
and R
4
are represented by f
1
, and those of the resonators R
2
and R
3
, by f
2
, the procedure for the design will be as follows.
(i) To determine the length L
2
′ of the inner electrodes
2
b
′ and
2
c
′ according to the resonance frequencies f
2
.
(ii) To determine the length S
2
′ of the region without the inner electrode and/or the intervals P
2
′ between the inner electrodes
2
b
-
2
c
′ according to the coupling amount K
2
, with consequent determination of the axial length L thereby.
(iii) To determine the length L
1
′ of the inner electrodes
2
a
′ and
2
b
′ according to the resonance frequency f
1
, with consequent determination of S
1
′.
(iv) To determine the interval P
1
′ between the inner electrodes
2
a
′-
2
b
′ and
2
c
′-
2
d
′ according to the coupling amount K
1
.
Although the symmetrical 4 stage band-pass filter may be designed in the manner as described above, since the interval P
1
′ and P
2
′ between the inner electrodes are not constant according to the filter characteristics aimed at, different metal molds are required for each kind of filter, thus resulting in high manufacturing cost.
SUMMARY OF THE INVENTION
Accordingly, an essential object of the present invention is to provide a dielectric resonator device constituted by providing resonance electrodes on a dielectric member, which is arranged to obtain necessary characteristics without changing intervals between the neighboring resonance electrodes.
Another object of the present invention is to provide the dielectric resonator device of the above described type in many kinds which are different in characteristics without increasing the number of molding metal molds required for manufacturing thereof.
A further object of the present invention is to provide a method of manufacturing the dielectric resonator device of the above described type in an efficient manner at low cost.
In accomplishing these and other objects, according to the present invention, there are provided the dielectric resonator device and the method of manufacturing said dielectric resonator device characterized in the points as follows.
STRUCTURAL ASPECTS
A dielectric resonator device according to a first aspect of the present invention is characterized in that it includes a dielectric block having a first face and a second face generally parallel to each other, side faces continuous between said first and second faces, and through-holes extending from the first face to the second face through the dielectric block, an outer electrode formed over said first face, said second face, and said side faces of said dielectric block, and first inner electrodes and second inner electrodes formed, through gaps, at least in the vicinity of opening portions at one side, on inner peripheral surfaces of said through-holes.
A dielectric resonator device according to a second aspect of the present invention is characterized in that it includes a dielectric block having a first face and a second face generally parallel to each other, side faces continuous between said first and second faces and through-holes extending from the first face to the second face through the dielectric block, an outer electrode formed over said first face, said second face, and said side faces of said dielectric block, and first inner electrodes and second inner electrodes formed, through gaps, in the vicinity of opening portions of said first face, on inner peripheral surfaces of said through-holes.
A method of manufacturing a dielectric resonator device according to a third aspect of the present invention is characterized in that it includes the steps of forming a dielectric block having a first face and a second face generally parallel to each other, side faces continuous between said first and second faces, and through-holes extending from the first face to the second face through the dielectric block, applying, through formation, an outer conductor film onto said first face, second face and side faces of said dielectric block, and also, applying, through formation, first inner conductor films and second inner conductor films through gaps, at least in the vicinity of opening portions at one side, onto inner peripheral surfaces of said through-holes.
A method of manufacturing a dielectric resonator device according to a fourth aspect of the present invention is characterized in that it includes the steps of forming a dielectric block having a first face and a second face generally parallel to each other, side faces continuous between said first and second faces, and through-holes extending from the first face to the second face through the dielectric block, applying, through formation, an outer conductor film onto said first face, second face and side faces of said dielectric block, and a
Kitaichi Yukihiro
Yamada Yasuo
Murata Manufacturing Co. Ltd.
Ostrolenk Faber Gerb & Soffen, LLP
Pascal Robert
Summons Barbara
LandOfFree
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