JPH05327315A - Dielectric filter - Google Patents

Abstract

PURPOSE:To simplify a metal die for formation and to unnecessitate lead wire connection by pulling out an inner conductive film, which is formed at the semi-divided hole of a dielectric semi-divided block, from the surface of a synthesized plane to the outside plane with a conductive film path and using the terminal as an input/output electrode. CONSTITUTION:Dielectric coaxial resonators 2a and 2b are composed of titanium oxide ceramic dielectrics and formed in the shape of rectangular parallelopiped bodies. A through hole 3 is formed by oppositely superposing two longitudinally bisected dielectric semi-divided blocks 4u and 4d provided with semi-divided holes on the inner faces for generating the through hole 3. These semi-divided blocks 4u and 4d respectively form semi-divided holes 5 and 5 on the inner faces for generating the through hole 2, and inner conductive films 6 and 6 are formed at the semi-divided holes 5. Further, outer conductive films 7 are formed on respective peripheral faces excepting for the superposed faces and the front face. The dielectric films 6 are pulled out from the surface of a synthesized plane (f) of the inner conductive films 6 and 6 to the outside face by a conductive film path 8 while being insulated from the conductive films 7, and the terminal is used as an input/output electrode 9. This electrode 9 and a required conductive path on a printed circuit board are electrically connected by soldering wax or the like. Therefore, the formation metal die is simplified and lead wires are unnecessitated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter having a plurality of dielectric coaxial resonators arranged in parallel.

[0002]

2. Description of the Related Art An axial through hole having an inner conductive film is formed on an inner peripheral surface thereof, and a connecting terminal electrically connected to the inner conductive film is fitted into the through hole so as to protrude from the front surface. In a dielectric filter constituted by arranging a plurality of dielectric coaxial resonators in which an outer conductive film is formed on a required outer peripheral surface, the dielectric coaxial resonator includes a half-hole that forms a through hole as an inner surface. The two vertical half-divided dielectric half blocks provided in the above are stacked in opposition to each other.
No. 1-156903 and the like.

[0003]

In the above configuration,
It is necessary to connect a lead wire to the inner conductive film formed in the through holes of the outermost dielectric coaxial resonators by soldering or the like. Therefore, lead wire drawing holes are formed in both sides of the dielectric half block in a direction orthogonal to the half holes, and the lead wires are drawn to the outside by the drawing holes. The internal dimension of the lead-out hole is formed to be large enough so that the thickness of the lead wire and the solder build-up portion do not interfere with the joining of the half blocks. In the half-divided block, the shape of the molding die is complicated, the molding cost is increased, and the strength of the whole half-divided block is unavoidable due to the drawing hole. It is an object of the present invention to provide a dielectric filter having a configuration that does not have such a problem and that does not require lead wire connection.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a dielectric coaxial resonator is formed by stacking two vertically-divided two-divided dielectric half blocks having a half-hole for forming a through hole on an inner surface. In addition to the above, the inner conductive film formed in the half-divided holes of the dielectric half blocks forming the outermost dielectric coaxial resonators is insulated from the outer conductive film from the superposed surface to the outer surface. It is characterized in that it is connected to the conductive film path formed by coating and the lead-out end formed on the outer surface of the conductive film path is used as an input / output electrode. Here, in the case where a dielectric filter is composed of two dielectric coaxial resonators, the outermost position means the two things.

[0005]

In the above structure, the coaxial resonators at both outermost positions are provided with the input / output electrodes electrically drawn from the inner conductive film to the outer surface through the conductive film path, and the printed circuit board. Electrical connection is made with a required electric circuit by solder wax or the like.

[0006]

1 to 3 show two dielectric coaxial resonators 2a,
An example in which the dielectric filter 1 is composed of 2b will be shown. Here, the dielectric coaxial resonators 2a and 2b are in the shape of a rectangular parallelepiped made of a titanium oxide-based ceramic dielectric, and have two vertical half-divided half-dielectrics having a half-hole for forming a through hole on the inner surface. It is configured by stacking the split blocks 4u and 4d in a facing manner, and the through hole 3 is formed by the stacking. In each of the dielectric half blocks 4u and 4d, a half hole 5 for forming a through hole 3 is formed on the inner surface thereof, and an inner conductive film 6 is formed in the half hole 5. Further, the outer conductive film 7 (7x) is formed on each peripheral surface except the overlapping surface and the front surface. The outer conductive film 7x formed on the adjacent surfaces of the dielectric coaxial resonators 2a and 2b may be removed.

Next, the main part of the present invention will be described. The dielectric half block 4 of the dielectric coaxial resonators 2a and 2b.
A conductive film path 8 is formed by screen printing on the non-adjacent overlapping surface f and the side surface of the dielectric half block 4d. The conductive film path 8 has the inner end thereof having the inner conductive film 6
Further, the outer conductive layer 7 is removed in a rectangular shape on the side surface side to be insulated so as to be a lead end, and the lead end is used as a rectangular input / output terminal 9. Then, the inner conductive film 6
Is electrically extended to the side surface side from the half-divided hole 5 by the conductive film path 8 through the overlapping surface. The dielectric coaxial resonators 2a and 2b are arranged on the printed circuit board p as shown in FIG.
It can be mounted adjacently on the upper side, and can be connected to the input / output terminal 9 by the required conductive path and the solder wax 30, etc., without using a lead wire.

Further, the metal connecting terminal 10 is tightly fitted into the through holes 3 and 3 formed by the half-divided hole 5 at the end positions thereof to ensure electrical connection with the inner conductive films 6 and 6. , 10 are mounted, and their small-diameter connection ends 11 project outward from the front surfaces of the dielectric coaxial resonators 2a and 2b.

Then, each of the dielectric coaxial resonators 2a, 2a
The dielectric substrate 20 is arranged in the front part of b. This dielectric substrate 20 is made of a ceramic dielectric.

As shown in FIGS. 1 and 4A, the dielectric substrate 20 has comb-teeth pattern conductors 22a and 22b arranged on its inner surface, and the comb portions are meshed with each other to form a capacitance pattern 21 formed by interstage coupling. ing. Further, as shown in FIG. 4B, a ground conductor 23 is formed on the outer surface of the dielectric substrate 20 so as to face the pattern conductors 22a and 22b continuously in the left and right direction. And each pattern conductor 22a, 22b
Insertion holes 24a and 24b are provided through the insertion holes 24a and 24b, and the connection terminals 10 connected to the inner conductive films 6 and 6 are inserted into the insertion holes 24a and 24b, and the pattern conductors 22a and 22b.
Electrically connected to. The conductive layer of the ground conductor 23 is removed at the peripheral portions of the fitting insertion holes 24a and 24b, so that the connecting terminal 1
0 and 10 are not electrically connected to the ground conductor 23. Then, one of the input / output terminals 9, 9 of each dielectric coaxial resonator 2a, 2b is connected to the input-side external electric path and the other is connected to the output-side external electric path. The ground conductor 23 is grounded via a case or the like.

Thus, the inner conductive film 6 is connected to the pattern conductors 22a and 22b, respectively, and as shown in FIG. 5, the coupling capacitance C ₁ is generated by the interstage coupling of the pattern conductors 22a and 22b. Further, each pattern conductors 22a, 22b are to face the ground conductor 23 via a dielectric substrate 20, caused the stray capacitance C _2, C ₃ therebetween is grounded.

In the above-mentioned embodiment, the dielectric filter 1 is composed of the two dielectric coaxial resonators 2a and 2b. However, three or more of the dielectric filters 1 may be arranged in parallel. In this case, The input / output terminal 9 is formed only on the outermost dielectric coaxial resonator, and on the inner surface side of the dielectric substrate 20, a plurality of pattern conductors equal in number to the dielectric coaxial resonators are interstage-coupled to form a plurality of couplings. The ground conductor 23 may be formed outside the dielectric substrate 20 so as to generate capacitance and cover each pattern conductor.

[0013]

As described above, according to the present invention, the dielectric half block 4d which constitutes the outermost dielectric coaxial resonator,
The inner conductive film 6 formed in the half-divided hole 5 is insulated from the outer conductive film 7 from the overlapping surface f to the outer surface and is drawn out by the conductive film path 8 and the drawn end is used as the input / output electrode 9. To complicate the molding die for the dielectric half block,
Since there is no need for a lead wire drawing hole that causes a problem such as a decrease in the strength of the block, it is easy and inexpensive to manufacture, and it is possible to achieve surface mounting on a printed circuit board that does not require lead wires. is there.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a dielectric filter 1.

FIG. 2 is a cross-sectional side view of the dielectric filter 1.

FIG. 3 is a vertical cross-sectional side view of dielectric coaxial resonators 2a and 2b.

FIG. 4 shows a dielectric substrate 20, where A is the inner surface and B is the outer surface.

FIG. 5 is an equivalent circuit diagram.

[Explanation of symbols]

 1 Dielectric Filter 2a, 2b Dielectric Coaxial Resonator 3,3 Through Hole 4u, 4d Dielectric Half-divided Block 5 Half-divided Hole 6,6 Inner Conductive Film 7 Outer Conductive Film 8 Conductive Film Path 9 Input / Output Terminals 10, 10 Connection terminal 20 Dielectric substrate

Claims (1)

[Claims] 1. An axial through hole having an inner conductive film is formed on an inner peripheral surface thereof, and a connecting terminal electrically connected to the inner conductive film is fitted into the through hole to protrude from the front surface. A dielectric filter configured by arranging a plurality of dielectric coaxial resonators, each having an outer conductive film formed on a required outer peripheral surface, wherein the dielectric coaxial resonator has a half-hole that forms a through hole as an inner surface. It is constructed by stacking two vertically-divided dielectric half-divided blocks facing each other, and at the half-divided holes of the dielectric half-divided blocks that compose both outermost dielectric coaxial resonators. The formed inner conductive film is connected to the outer conductive film from the overlapping surface to the outer surface and connected to the conductive film path formed by coating, and the lead end formed on the outer surface of the conductive film path serves as an input / output electrode. A dielectric filter characterized by the above.