JPS61261902A - Earth structure of dielectric coaxial resonator - Google Patents

Abstract

PURPOSE:To facilitate the connection of a resonator to an earth of an outer conductor by cutting and raising a part of a metallic case whose shield plate is conded conductively to form a spring piece and pressing the piece to the outer conductor of a dielectric coaxial resonator. CONSTITUTION:The metallic case 51 is formed with spring pieces 58a, 58b and 59a, 59b... formed by cutting and raising side plates 51a, 51b obliquely inward opposed to each outer conductor 3 of resonators 1-1, 1-2, 1-3 and 1-4. Thin shield plates 63a, 63b are bonded conductively to the side plates 51a, 51b of the metallic case 51 in order to prevent the leakage of an electromagnetic wave from an opening formed by the spring pieces 58a, 59a and the spring pieces 58b, 59b.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a grounding structure for a dielectric coaxial resonator using a cylindrical dielectric.

A dielectric coaxial resonator, for example, the 74-wavelength coaxial TEM resonator 1 shown in FIG. More specifically, on the inner and outer wall surfaces of the thick pipe-shaped dielectric material 4, there is a material having excellent high frequency conductivity and good adhesion to the dielectric material 4, for example. The inner conductor 2 and the outer conductor 3 are formed by baking silver paste. The inside of the inner conductor 2 is hollow, and there is a dielectric material 4 made of a similar ceramic or the like.
A center rod 5 with a longer axial length is fitted and fixed, and one end 6 of the center rod 5 protrudes from the open end surface 7 of the resonator l and is covered with an electrode film 8 extending from the inner conductor 2. be. 9
is an electrode that short-circuits the inner conductor 2 and the outer conductor 3.

FIG. 6 is a diagram showing only the essential parts of another resonator 11, and shows a case where the center rod 5 is not used. In this case, a terminal electrode I2 of an arbitrary shape is fitted into a hole surrounded by an inner conductor 2. , fixed with conductive adhesive and connected to the inner conductor 2. On the other hand, 13.14
is a chip-shaped capacitor, which is used to capacitively couple the resonator II to other components, such as another resonator or connector. That is, the upper part of the terminal electrode 12 is shaped appropriately, and one electrode 15.16 of the chip capacitor 13.14 is connected to the other electrode 17.18 of the chip capacitor 13.14, while one end of the lead wire 19.20 is connected to the other electrode 17.18 of the chip capacitor 13.14. The other ends of the lead wires 19 and 20 are connected to, for example, another resonator or connector.

FIG. 7 shows a filter 21 constructed using the above-mentioned resonator, particularly the one shown in FIG. 6.

The same parts as in FIG. 6 are shown with the same numbers.

22 is a case. The case 22 is a rectangular parallelepiped made of a conductor, for example, noduralumin, and has grooves 23, 24, 2 each having a semicircular cross section.
5.26 are formed in parallel with a slight interval. Also, grooves 23 and 24, #24 and 25, grooves 25 and 26
Grooves 27, 28, and 29 each having a semicircular cross section are formed across the grooves.

Further, a groove 31 is formed between the groove 23 and the outside of the case 22, and a groove 32 is formed between the groove 26 and the outside of the case 22. i'W31, 27, 28, 29.32 are on a straight line. In case 22, as shown in FIG.
The product is completed by covering it with a case 33 having the same structure as 2.

In other words, as shown in FIG. 8, the case 22 corresponds to one half of a rectangular case divided into two along the longitudinal section. There are resonators l in the grooves 23, 24, 25, and 26.
1 is inserted into each half, and its outer conductor 3 is inserted into the case 22.
is electrically connected and fixed. This fixing is performed, for example, by using a conductive adhesive or by screwing. 34 is an input coaxial connector that is half fitted into the groove 31, and 35 is an output coaxial connector that is half fitted into the groove 32. Both connectors 34, 35 are secured to the case 22, 33 in a manner known in the art. The center terminal of the input coaxial connector 34 and the capacitor 13 of the first stage resonator 11 are connected by a lead wire 36. The capacitor 14 of the first stage resonator 11 and the capacitor 13 of the second stage resonator 11 are connected by a lead wire 37 through the groove 27. The capacitor 14 of the second stage resonator 11 and the capacitor 13 of the third stage resonator 11 are connected by a lead wire 38 through the groove 28. The capacitor 14 of the third stage resonator 11 and the capacitor 13 of the fourth stage resonator II are connected by a lead wire 39 through the groove 29. The capacitor 14 of the fourth stage resonator 11 and the center terminal of the output coaxial connector 35 are connected by a lead wire 40.

As is clear from the filter structure described above as an example, conventionally, as shown in FIG. 9, the outer conductor 3 of the resonator 11 is grounded to the case 22. Alternatively, as shown in FIG. 1O, the outer conductor 3 of the resonator 11 and the case 22.3
The outer conductor 3 of the resonator 11 is
was grounded to cases 22 and 33, and both were fixed together.

By the way, as mentioned above, when the leaf spring 42 is used, the leaf spring 42 is interposed between the case 22.33 and the resonator II, so the case 22.33 absorbs the spring force of the leaf spring 42. The resonator 11 needs to be thick enough to withstand the above-mentioned conditions, and there is a problem in that the shape of a product such as a filter using the resonator 11 becomes large. On the other hand, when the outer conductor 3 of the resonator 11 is fixed to the case 22.33 using the conductive adhesive 41, the linear expansion coefficient of the resonator 11 is greatly different from that of the case 22.23 and the adhesive. Therefore, there was a problem that the outer conductor 3 would peel off due to sudden temperature changes. In addition, the work is troublesome and it takes a long time to harden, which is a factor in increasing costs.

(Object of the Invention) The present invention has been made to solve the above-mentioned problems in the conventional grounding structure of a dielectric coaxial resonator. An armor collar for a dielectric coaxial resonator that does not cause peeling of the outer conductor, etc. and makes products incorporating a dielectric coaxial resonator more compact.
) Bus 1) (Structure of the Invention) Therefore, the present invention provides a structure in which a dielectric coaxial resonator is housed in a metal case made of a thin metal plate having spring properties, and a part of the metal case is cut out. The formed spring piece is in pressure contact with the outer conductor of the dielectric coaxial resonator, and a shield plate is electrically conductively adhered to the surface of the metal case where the spring piece is cut and raised. .

That is, in the present invention, a spring piece is formed by cutting and raising a part of a metal case made of a thin metal plate having spring properties, and this spring piece is pressed against the outer conductor of a dielectric coaxial resonator to form a dielectric coaxial resonator. The resonator is fixed in the metal case and the outer conductor is electrically connected to the metal case.The hole formed in the cut and raised part of the spring piece is conductively bonded to the metal case. It is closed by a shield plate.

(Effects of the Invention) According to the present invention, since the dielectric coaxial resonator is fixed and the outer conductor is connected to the ground using the spring piece formed in a part of the metal case, the dielectric coaxial resonator Dimensional changes due to thermal expansion of the metal case are absorbed by the spring piece, preventing the outer conductor from peeling off. Also, since the spring piece is formed on a part of the metal case, an independent spring member can be used. Compared to the case where a dielectric coaxial resonator is fixed to a metal case by using a dielectric coaxial resonator, the wall thickness of the metal case can be made thinner.
It is possible to reduce the size of products such as microwave filters using dielectric coaxial resonators.

(Example) Hereinafter, the present invention will be specifically described with reference to the accompanying drawings regarding an example in which the present invention is applied to a microwave filter.

In FIG. 1, a 174-wavelength coaxial TEM resonator 1-1.1- explained in FIG.
2.1-3 and 1-4 are accommodated. These 1/
4-wavelength coaxial TEM resonator 1-1.1-2. I-3 and I-4 are arranged in parallel in the metal case 51 with their respective axial directions aligned.

Above 1/4 wavelength coaxial TEM resonator 1-1.1-2.1-
An electrode film 8 (see FIG. 5) extending from the inner conductor 2 of the dielectric 4 of each center rod 5 of 3 and 1-4 is soldered to an electrode 53 formed on a bonding substrate 52. This bonding substrate 52 has a dielectric plate 54 made of ceramic or the like having a constant width.
The electrodes 53.53. ... are formed, and due to the capacitance formed between adjacent electrodes 53.53, the center rod 5.
Adjacent resonators 1- to which electrode films 8, 8 of No. 5 are soldered;
1 and 1-2. Resonators 1-2 and 1-3 and resonators 1-3
and 1-4 are electrostatically coupled to each other.

At both ends of the dielectric plate 54, electrodes 55°55(
In FIG. 1 one of the electrodes 55,55 is not visible. )
are formed, and these electrodes 55.55 are the center conductor 56a of the input coaxial connector 56 attached to the metal case 51,
It is soldered to the center conductor 57a of the output coaxial connector 57.

On the other hand, the resonator 1-1. I-2, 1-3 and rK I
-A 7', JT7'lS eggplant To road &-7'1
As shown in F9M, spring pieces 58a, 58a, ...
and 59a, 59a, . . . are formed. Another side plate 51b opposite to the side plate 51a is also provided with spring pieces 58b, 58b, . . . and 59b, 59b, .
・is formed.

The spring pieces 58a, 58a, ... and 59a, 59
a.

... means that the side plate 51a of the metal case 51 is attached to the metal case 5.
The resonators accommodated in the resonators 1]-1, 1-2, 1-3, and 1-4 are cut and raised obliquely inward. Also, spring pieces 58b, 58b.

. . , 59b, 59b, . -4
It is cut diagonally inward to correspond to the shape.

Resonator 1-1.1-2. Both I-3 and 1-4 are held in the metal case 51 between spring pieces 58a and 58b and between spring pieces 59a and 59b by their spring force.

Note that the spring pieces 58a and 58b are connected to the resonator 1-1 through which a large high-frequency current flows. l-2, 1-3 and I-4
It is preferable that the outer conductor 3 be brought into pressure contact with the outer conductor 3 near each open end.

The metal case 51 has an opening 62 between its side plates 51a and 51b, into which a lid member 61 is fitted and fixed,
From this opening, the resonator 1-1.1-2. I-3 and 1-4 are accommodated.

The side plates 51a and 51b of the metal case 51 are provided with spring pieces 58a, 59a and a spring piece 58b.

In order to prevent electromagnetic waves from leaking from the opening formed by 59b, thin shield plates 63a and 63b are provided.
are conductively bonded.

With the above configuration, the resonators 1-1゜1-2.1-3 and 1-2. 1-4 are the spring pieces 58a and 58b and the spring piece 59a.
and 59b, each outer conductor 3 of the resonators 1-1, 1-2, 'I-3 and I-/l
The high frequency current of the spring pieces 58a, 58b, 59a and 59b, especially the resonator 1-1. It is bypassed to the metal case 51 through the spring pieces 58a and 58b near the open ends of I-2, 1-3 and l-4.

In the microwave filter shown in FIG. 1, even if the dimensions of the metal case 51 and the resonators 1-1.1-2.1-3 and l-4 change due to thermal expansion, the resonators l-1, 1- 2,1-3
And the outer conductor 3 of 1-4 does not peel off from the dielectric 4.

Also, a part of the metal case 51 includes resonators 1-1, 1-2.
Since spring pieces 58a and 58b and spring pieces 59a and 59b are formed to sandwich resonators 1-1, 1-2. I-3 and 1-4 in metal case 5
There is no need for special members or conductive adhesive to be fixed within the device. Furthermore, the force applied to the metal case 5I is small, the thickness of the material of the metal case 51 is also reduced, and the shape of the microwave filter is also reduced.

In the above embodiment, the spring pieces 58a, 59a and 58b, 59b may have their tips bent toward the outside of the metal case 51, as shown in FIG.

Further, as shown in FIG. 4, the side plate 5I of the metal case 51
Protrusions 65a, 65b that protrude inside the metal case 51 are formed by extrusion on the b side, and these protrusions 65a, 6
5b between resonators 1-1. l-2, 1-3 and 1-4
may be positioned.

The present invention can be applied not only to microwave filters but also to devices such as duplexers.

Further, the present invention can be applied to the grounding structure of the 1/4 wavelength dielectric coaxial resonator and the 1/2 wavelength dielectric coaxial resonator described in FIG.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of a microwave filter to which the present invention is applied, FIG. 2 is a sectional view showing the internal structure of the microwave filter of FIG. 1, and FIG. 3 is a cross-sectional view of the microwave filter of FIG. A cross-sectional view of a spring different from the spring piece, Fig. 4 is an explanatory diagram of an example in which a part of the spring piece is replaced with a protrusion in the microwave filter of Fig. 1, and Fig. 5 is a 1/4 wavelength coaxial TEM resonator. A cross-sectional view of an example, FIG. 6 is a cross-sectional view showing the main parts of another 1/4 wavelength coaxial TEM resonator, and FIG. 7 is an internal explanatory diagram of a filter having a ground structure of a conventional dielectric coaxial resonator. , FIG. 8 is a top view of the filter shown in FIG. 7, and FIGS. 9 and 10 are sectional views taken along the line AB in FIG. 7, respectively, showing the conventional structure. ■-・l-1-4...1/4 wavelength coaxial TEM resonator,
2...Inner conductor, 3...Outer conductor, 4...
- Dielectric, 5... Center rod, 7... Open end surface, 51... Metal case, 58a, 58
b, 59a, 59b--spring piece, 63a, 63
b-shield plate 65a, 65b-protrusion.

Claims (1)

[Claims] (1) An inner conductor and an outer conductor are formed on the inner and outer circumferential surfaces of a cylindrical dielectric, respectively, and these inner and outer conductors are short-circuited by a shorting conductor formed on one end surface of the dielectric. A dielectric coaxial resonator made of a dielectric coaxial resonator is housed in a metal case made of a thin metal plate having spring properties, and a spring piece formed by cutting and raising a part of this metal case serves as an outer conductor of the dielectric coaxial resonator. A grounding structure for a dielectric coaxial resonator, characterized in that a shield plate is electrically conductively adhered to the surface of the metal case from which the spring piece is cut and raised.