JPH0449702A - Dielectric filter - Google Patents

Abstract

PURPOSE:To stabilize characteristic by surely preventing a dielectric substrate approaching an open side end face by an external force by forming a positioning part, and a gap specified between the open side end face and the substrate by the positioning part at a case. CONSTITUTION:A dielectric filter 20 is comprised by arranging five dielectric coaxial resonators 2 of lambda/4 in parallel. The assembly of the resonators 2 is housed in a metallic case main body 21, and a case cover 22 formed in box shape is loaded on the main body 21. First positioning parts 28, 28 and a second positioning part 29 are formed at the bottom wall 21a of the main body 21. The front end face 28a of the positioning part 28 is located at a position a little before than the positioning part 29, and the rear end face 9c of a dielectric substrate 9 is abutted with the front end face 28a. Thereby, the gap (a) is provided between the rear end face 9c of the substrate 9 and the open side end face 4a of the resonator 2, and the gap (a) is set so as to provide with thickness >=1/3 the thickness (t) of the substrate 9.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a dielectric filter in which dielectric resonators are capacitively coupled to each other via, for example, a substrate on which a capacitor electrode film is formed. No place! The present invention relates to a structure that can prevent adverse effects on characteristics due to misalignment, and also improve workability during assembly by ensuring the positioning of the substrate and dielectric resonator.

[Conventional technology]

For example, a conventional dielectric filter using a plurality of dielectric coaxial resonators has a structure shown in FIG. 9. This dielectric filter l is constructed by housing a plurality of dielectric coaxial resonators 2 in a case 3. Each dielectric coaxial resonance 52 has a rectangular parallelepiped shape #! ! , 'A T1 block 4 is formed, and a white field electric film 6 and an outer conductor 11M1 are formed on the inner peripheral surface of the through hole 5 and the outer surface of the dielectric block 4 excluding the open end surface 4a, respectively. formed and composed. Further, a cylindrical body 8a of a coupling terminal 8 is press-fitted into the through hole 5 on the open side end surface 4a side of the dielectric block 4.
A connecting piece Bb integrally formed on the cylindrical body 8a projects outward. Furthermore, a rectangular dielectric substrate 9 is disposed on the open end surface 4a side. A capacitor electrode film 9a is formed on one surface of the substrate 9, and a connecting piece 8b of the coupling terminal 8 is soldered to each electrode film 9a.

Furthermore, output terminals 10 are soldered to both ends of the dielectric substrate 9, and each terminal 10 projects outward from the opening of the case 3. Further, a solder hole 3a is formed in the contact surface of the dielectric block 4 of the case 3, and is electrically and mechanically connected to the outer conductor 7 by solder 11 filled in the solder hole 3a. . As a result, a dielectric filter 1 is constructed in which the dielectric coaxial resonators 2 are capacitively coupled to each other.

[Problem that the invention seeks to solve]

However, in the conventional filter described above, it has been found that when the dielectric substrate 9 is too close to the open end surface 4a of the coaxial resonator 2, variations in characteristics occur. This is considered to be due to the following reasons. That is, the electric field of the coaxial resonator 2 is transmitted not only inside the resonator 2 (see Fig. 9 (solid line - mark)) but also outside the open side end surface 4a from the white field Wi, 6 to the outer field 7.
When the substrate 9 approaches the open end surface 4a, the electric field on the outside is blocked by the substrate 9, which adversely affects the characteristics.

To avoid the adverse effects of the board, connect the connecting piece 8b of the coupling terminal 8.
It is considered that a gap may be provided between the dielectric substrate 9 and the coaxial resonator 2 when the dielectric substrate 9 is soldered to the coaxial resonator 2. However, in the conventional dielectric filter I, for example, when some external force is applied to the dielectric substrate 9 during mounting, the coupling terminal 8 tends to move inward of the through hole 5.
Since the substrate 9 also moves along with this, there is a concern that the size of the gap changes, and as a result, the characteristics vary.

Further, the work of fixing the coupling terminal 8 to the dielectric base Fi9 by soldering while providing the gap is complicated, and there is also the problem that the workability is poor.

The present invention has been made to solve the above-mentioned conventional problems, and it is possible to reliably prevent the dielectric substrate from approaching the open end surface due to external force, thereby stabilizing the characteristics, and also to prevent soldering of the coupling terminal. The purpose is to provide a dielectric filter that can improve workability.

[Means for solving problems]

The present invention provides a dielectric filter in which a dielectric resonator is disposed within a case, and the resonator is connected via a coupling terminal to a substrate disposed on an open end surface of the resonator, in which the case includes: A positioning portion is formed to regulate the distance between the substrate and the open end surface of the dielectric resonator, and the positioning portion provides a gap of 173 mm or more of the substrate thickness between the open end surface and the substrate. It is characterized by

Here, the reason why the gap is set to be 173 or more times the thickness of the substrate is because if it is less than this, it is impossible to avoid blocking of the electric field, and the effect of preventing adverse effects on the characteristics cannot be obtained.

[Effect]

According to the dielectric filter according to the present invention, the positioning portion is formed in the case, and the substrate and the dielectric resonator are brought into contact with the positioning portion to provide a predetermined gap between them.
Even if an external force is applied to the substrate, the i-substrate will not move toward the open end face, and the gap between them can be kept constant, making it possible to stabilize the characteristics.

Further, in the present invention, when connecting the coupling terminal and the board, the board is brought into contact with the positioning part, and the open end surface of the dielectric resonator is brought into contact with the board to fix it, and soldering is performed in this state. Therefore, the complicated work of positioning while soldering is unnecessary.
Work efficiency can be improved accordingly.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 are diagrams for explaining a dielectric filter according to an embodiment of the present invention, and in the figures, the same reference numerals as in FIG. 9 indicate the same or corresponding parts.

The dielectric filter 20 of this embodiment has five dielectric coaxial resonators 2 of λ/4 arranged in parallel, and capacitor electrodes 1! 9g is formed, and the connection piece 8b of the coupling terminal 8 is soldered to the capacitor electrode film 9a, and the output terminal 10 is soldered to both ends of the dielectric substrate 9. are connected to each other, thereby coupling the coaxial resonators 2 to each other by capacitance, and the basic structure is substantially the same as that of the conventional one.

-Reporter The assembly of the dielectric coaxial resonator 2 is housed in a metal mousse body 21, and a box-shaped case cover 22 is attached to the case body 21. Further, a label 23 is attached to the earthen wall 2'2ia of the case cover 22.

The case body 21 has side walls 21b standing up on the left and right edges of a bottom wall 21a on which the dielectric coaxial resonator 2 is placed, and a front wall 21e standing up on the front edge of the bottom wall 21a. The output terminal 10 protrudes from the left and right openings of the front wall 21C.

In addition, a downwardly facing retaining piece 24 is formed on a part of each side wall 21b and the front wall 21C by cutting and raising it outward.1. An engagement hole 25 formed in the case cover 23 fits into the engagement piece 24 .

Further, solder holes 26 and 27 are formed in the bottom wall 21a of the case body 21 and the clay wall 22a of the case cover 22, respectively, in the portions that the coaxial resonator 2 comes into contact with. 27 is filled with solder, whereby each coaxial resonator 2 is mechanically and mechanically connected and fixed.A first right corner of the bottom wall 21a of the case body 21 is provided with a first A positioning portion 28.2B is cut inward and formed to stand up, and the first positioning portion 28 is located on the left side,
It is in contact with the coaxial resonators 2 at both right ends. Further, at the front edge of each solder hole 26 of the bottom wall 218, a second positioning portion 29 is provided.
is formed by bending upward 9, and each second positioning portion 29 is in contact with the open side end surface 4a of each coaxial resonator 2. Further, a support portion 30 is formed by bending inward at the front portion of each side wall 21b, and both ends of the dielectric substrate 9 are placed on the upper surface of the support portion 30.

Further, a substantially U-shaped fixing portion 31.degree. 31 is provided inwardly to protrude from the front wall 21C, and the fixing portion 31 abuts the front end portion 9h of the dielectric substrate 9 L7.

The front end surface 28a of the first positioning part 28 is located slightly 2 points forward of the second positioning part 29,
This front end surface 28a has the above y; the rear end surface 9c of the dielectric substrate.
are in contact with each other. With this, Juki! A gap a is provided between the rear end surface 9c of the y8 electric substrate 9 and the open end surface 4a of the coaxial resonator 2, and this gear knob a has a thickness of 1/3 or more of the thickness t of the dielectric substrate 9. It is set to be. Specifically, the thickness of the substrate 9 is sealed to lmi, and the gap a is approximately 0.5 to 1.

Next, the effects of this embodiment will be explained.

To assemble the dielectric filter 20, first, a person places the dielectric substrate 9 to which the output terminal 10 is soldered onto the case body 2.
The dielectric substrate 9 is placed on the support section 30 of the substrate 1, and the substrate 9 is held between the first positioning section 28 and the fixing section 31, thereby positioning the dielectric substrate 9 in the area direction.

Next, each coaxial resonator a2 into which the coupling terminal 8 is press-fitted is placed on the bottom wall 21a of the case body 21, and the side surface of the resonator 2 is brought into contact with the first position determining part 28, and The resonator 2
The open side end surface 4a of the coaxial resonators 2 are brought into contact with the second positioning part 29, and the coaxial resonators 2 are sequentially arranged. This allows each coaxial resonator 2
is held between the first positioning parts 28 in the left and right directions, and is positioned in the front-rear direction by the second positioning parts 61!29. After this time, attach the connecting piece 8b of the F reporter coupling terminal B to the capacitor electrode film 9a (2), then attach the case cover 22 and attach each solder hole 26.
．． 27 is filled with half I] and fixed.

As described above, according to the present embodiment, the case main body 21 has the first.
When the second positioning parts 28 and 29 are formed 7 and the dielectric substrate 9 is brought into contact with the first positioning part 28, the open side end surface 4a of the coaxial resonator 2 is brought into contact with the second positioning part 29. Since a predetermined gap a is provided between the two, the inward movement of the dielectric substrate 9 is reliably restricted.
Even if an external force is applied to the substrate 9, the gap a can be maintained, and as a result, an adverse effect on the electric field can be avoided, variations in characteristics can be prevented, and quality reliability can be improved.

Further, in this embodiment, as explained in the assembling procedure of the dielectric filter 20, the case body 21 has a dielectric substrate 9.
．． Since the coaxial resonators 2 are sequentially arranged and positioned, and then the coupling terminals 8 are soldered to the capacitor electrode film 9a, the conventional time-consuming work of positioning while soldering can be eliminated, which makes the work easier. This makes it possible to simplify the adjustment work of filter characteristics and improve yield.

In the above embodiment, the case where the first and second positioning portions 28 and 29 are formed by cutting and raising the case body 21 was explained as an example, but various modifications can be considered for the shape of the positioning portion of the present invention. It will be done.

For example, as shown in FIG. 4, the bottom of the case body 21! 21
A substantially triangular positioning portion 40 is cut and raised between the coaxial resonator 2 of a and the dielectric substrate 9, and the positioning portion 4
A gap may be provided with a width of 0.

Alternatively, as shown in FIG. 5, a positioning portion 41 may be cut and raised at the contact portion of the coaxial resonators 2, and a gap may be obtained by the plate thickness of the positioning portion 41. In this case, If the plate thickness of the positioning part 41 is thin and the gap is too small, as shown in FIG. 6, a protrusion 41a may be formed on the positioning part 41, and the gap may be made larger by the protrusion 41a. Furthermore, as shown in FIG. 7, the positioning part 42 may be formed by cutting and raising the positioning part 42 inward on the side wall 21b of the case body 21, and the same effects as in the above embodiment can be obtained in each of the above modifications.

FIG. 8 shows another example of fixing the dielectric substrate 9, in which a downward protruding piece 30M is formed on the upper part of the supporting part 30, and the substrate 9 is held between the protruding piece 30a and the supporting part 30. This is an example.

Further, in the above embodiments, a filter using a dielectric coaxial resonator was explained as an example, but the present invention can also be applied to an integrally molded dielectric filter, and can also be applied to a deburexer.

(Effects of the Invention) As described above, according to the dielectric filter according to the present invention, the positioning portion is formed in the case, and the predetermined gap is provided between the dielectric resonator and the substrate by the cough positioning portion. This has the effect of reliably preventing movement of the substrate due to external force and stabilizing the characteristics, as well as facilitating positioning and improving workability.

[Brief explanation of drawings]

1 to 3 are diagrams for explaining a dielectric filter according to an embodiment of the present invention, in which FIG. 1 is a perspective view showing a positioning part thereof, FIG. 2 is a cross-sectional side view thereof, and FIG. The figure is an exploded perspective view of the same, FIGS. 4 to 7 are views showing modified examples of the positioning section, and FIG. Its perspective view, Fig. 6 (+1) and Fig. 6 (bl are respectively its perspective view and cross-sectional side view, Fig.
)) and FIG. 8 (bl is a perspective view showing another fixing structure of the dielectric substrate, respectively. A sectional view, FIG. 9 (&) and FIG. 9 (bl is a perspective view showing a conventional dielectric filter, respectively. It is a sectional view. In the figure, 2 is a dielectric resonator, 4a is an open side end surface, and 8 is a dielectric resonator.
is a coupling terminal, 9 is a dielectric substrate, 2o is a dielectric filter,
21 is the case body, 28.29°, 40.41.42 is a positioning portion, and a is a gap. Figure 1 '10 Figure 2 1a Figure 4 Figure (a) Figure 7 Figure 8 (b)

Claims (1)

[Claims] (1) A dielectric filter in which a dielectric resonator is disposed within a case and the resonator is connected via a coupling terminal to a substrate disposed on the open end surface of the resonator, in which the above-mentioned A positioning portion is formed to regulate the distance between the substrate and the open side end face of the dielectric resonator, and the positioning portion allows a gap between the open side end face and the substrate to be 1/1/2 of the substrate thickness.
A dielectric filter characterized by having three or more gaps.