JPS62271503A - Dielectric resonator - Google Patents

Abstract

PURPOSE:To adjust the resonance frequency over a wide range without reduction of the Q by moving a tuning unit of a dielectric freely in radial direction of a dielectric resonator element. CONSTITUTION:In turning a rotary shaft 42, a tuning unit 28 is moved in radial direction of the dielectric resonator element 24 fixed to a metallic case by the coupling between a pinion and a rack. Thus, the effective dielectric constant of the element 24 is changed and the resonance frequency is adjusted over a wide range without decreasing the Q.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) This invention relates to a dielectric resonator, and particularly to adjusting the resonant frequency of a dielectric resonator using the TEo+ mode or its modified mode. Concerning the structure of

(Prior art) An example of the prior art is Utility Model Application No. 57-122909.
Disclosed in the issue. In this conventional technology, a dielectric material is supported in a metal case to realize a TEQI6 mode dielectric resonator, and a screw is attached to the metal case, and the screw is moved up and down to bring it closer to the dielectric resonator element. Alternatively, the resonant frequency is adjusted by moving it away. For example, the closer a metal screw is to its dielectric resonator element, the higher the resonant frequency will be.

(Problem to be solved by the invention) When the resonant frequency is changed from fo to fo', the no-load Q changes from Qo to QO', but in the conventional technology using metal screws, for example, the resonant frequency The rate of change (1(fo'-fo)/foIX100) is 3.5%
, the fluctuation rate of QO (1(Qo' - Qo)
/Qol x I 00) was, for example, 20%.

That is, in the conventional technology, the rate of change of the resonant frequency is 3.5.
%, the Qo fluctuation rate was as high as 20%, making it unsuitable for practical use.

Therefore, the main objective of the present invention is to provide a dielectric resonator whose resonant frequency can be adjusted over a wider range without significantly lowering the QO.

(Means for Solving the Problems) Simply put, the present invention includes a conductor case, a dielectric resonator element fixed within the conductor case, a tuning unit made of a dielectric combined with the dielectric resonator element, and displacement means for displacing the tuning unit in the radial direction of the dielectric resonator element.

(Operation) A tuning unit made of a dielectric changes the effective permittivity (ε) of the dielectric resonator element, thereby changing the resonant frequency based on perturbation theory.

(Effects of the Invention) According to the present invention, since a metal screw is not used as in the conventional case, that is, a tuning unit made of a dielectric material is used, so there is no reduction in QO due to current concentration. Therefore, even if the resonant frequency is changed over a wide range, the fluctuation rate of the QO can be reduced compared to the conventional one.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

(Example) FIG. 1 is an illustrative cross-sectional view showing one embodiment of the present invention.

The dielectric resonator 10 includes a bottomed cylindrical case 12 made of a conductive material such as aluminum. A top cover 14 made of aluminum is similarly fixed to the upper end of the case 12. An input terminal 18 and an output terminal 20 are provided on the bottom 16 of the case 12 so as to protrude into a shielded space sealed by the case 12 and the top lid 14 .

Incidentally, instead of the conductive case as described above, the case may be made of a dielectric material such as ceramic, and the inner and/or outer surfaces thereof may be For example, an electrode made of silver or the like may be formed to define the shield space.

Inside the case 12, a cylindrical support 22 made of a low dielectric material is attached on the bottom 16 at approximately the center thereof. A hollow cylindrical dielectric resonator element 24 made of a dielectric material with a high dielectric constant, such as titanium oxide ceramic, is fixed onto the support base 22 . Therefore, the dielectric resonator element 24 is fixedly held within the case 12, and the dielectric resonator 10 that utilizes the TEOI 6 mode is configured as a whole.

On the inner wall of the hollow part 26 of the dielectric resonator element 24, a second
As shown in the figure, the top view of the case with the top cover removed.
Two recesses 28 are formed facing each other.

A rectangular parallelepiped-shaped tuning unit 30 made of a dielectric material with a high dielectric constant such as ceramic is relatively loosely fitted into each of the opposing recesses 28 . Therefore, this tuning unit 30 each has the following characteristics:
It can be displaced in the direction of the arrow in FIG. Further, the height of the tuning unit 30 is equal to that of the dielectric resonator element 2.
The length and height in the axial direction of 4 are selected to be approximately equal to each other. However, this height may be longer (or shorter than the height of the dielectric resonator element 24).

On the opposing surface 32 of the tuning unit 30, a third
As shown in a perspective view in the figure, guides 34 or 36 made of a dielectric material with a relatively low dielectric constant, such as ceramic, are fixed alternately. Also, side 3
Similarly, the square hole 3B or 40 for receiving the guide 34 or 36 extending from the opposing tuning unit 30 from its tip end is provided in the tuning unit 30 of the opposite partner.
They are arranged alternately. Although not shown in detail, racks are formed on opposing inner surfaces of these guides 34 and 36 in the length direction thereof.

A rotating shaft 42 is inserted between the guides 34 and 36,
A pinion that meshes with the rack described above is formed at a portion of the rotating shaft 42 that contacts the guides 34 and 36.

Therefore, if the rotary shaft 42 is rotated, the rotational movement of the shaft 42 is converted into a linear movement of the guides 34 and 36 by coupling means, such as a rack and pinion, and the tuning unit 30 is accordingly converted into a linear movement of the dielectric resonator element. 24
will be displaced in the radial direction. For example, the rotating shaft 42
When the guide 34 is rotated to the right (clockwise), the guide 34 moves to the left and the guide 36
are respectively displaced to the right, so the opposing two
The two tuning units 30 will be displaced in opposite directions and will spread outward. Conversely, when the rotating shaft 42 is rotated to the left (counterclockwise), the tuning units 30 are displaced in a direction toward each other.

As shown in FIG. 1, the rotation shaft 42 passes through the bottom 16 of the case 12, the center of the top lid 14, and the hollow portion of the dielectric resonator element 24, and connects the bottom 16 and the top lid 14.
are rotatably supported by bearings 44 provided respectively. Therefore, by rotating the shaft 42 from outside the case 12, the tuning unit 30 can be displaced in the above-mentioned direction, that is, in the radial direction of the dielectric resonator element 24.

The reason why the resonant frequency fO can be changed in such a structure will be explained using the following perturbation equation.

Where, fO: resonant frequency before perturbation, Δf: change in resonant frequency due to perturbation, Wt: time average of total energy in the resonator, Δε: change in permittivity, EI: electric field vector before perturbation, E2* : conjugate electric field vector after perturbation, V; effective volume of the dielectric resonator instrument 24.

As can be seen from this perturbation equation, when the tuning unit 30 is displaced in the radial direction from the center to the outside in the electric field intensity distribution as shown in FIG. A'E I 'E2
``dv increases.The shift force causes the resonant frequency fo to decrease.When the tuning unit 30 is displaced from the outside toward the inside, the resonant frequency fo conversely increases.

According to experiments conducted by the inventors, such a dielectric resonator 10
In this case, when the tuning unit 30 was displaced and the rate of change in the resonance frequency was 3.5%, the rate of change in Qo ΔQo was 7%. That is, as is clear from this result, even if the tuning unit 30 is displaced in the radial direction and the resonant frequency fO is changed as in the conventional case,
The change in Qo could be suppressed to about 1/3.

In the above-described embodiment, an example was described in which two opposing tuning units 30 were provided, but the number of tuning units is arbitrary as shown in FIGS. 6 to 9. For example, in the case of FIG. 6, a plurality of tuning units 30 are shown arranged radially in the radial direction of the dielectric resonator element 24. In FIG. In FIG. 7, only one tuning unit 30 is arranged. In the case of FIG. 8, a plurality of tuning units 30 are arranged, and as shown in a vertical cross-sectional view in FIG. It is located approximately in the upper half of the

Further, the tuning unit 30 includes the dielectric resonator element 2.
However, the tuning units 30 may be arranged in different levels, that is, in two different planes, as shown in FIGS. 10 to 13.

In the embodiment shown in FIGS. 10 and 11, the tuning units 30 are arranged at different levels, and the hole 48 for receiving the tuning unit 30 penetrates from the hollow part 26 of the dielectric resonator element 24 to the outer surface 5o. It is formed by In the embodiment shown in FIGS. 12 and 13, the tuning unit 3o is similarly arranged in a staggered manner, but the hole 52 does not pass through the outer surface 50.

Further, in the above-described embodiments, the dielectric resonator element 24 is described as having a hollow cylindrical shape, but it may be solid as shown in FIGS. 14 to 18.

In the embodiment shown in FIG. 14, the tuning unit 30
is disposed in a housing portion 54 formed on the top of the solid cylindrical dielectric resonator element 24 .

In the embodiment shown in FIG. 15, tuning units 30 are disposed in respective housing portions 54 formed at the upper and lower portions of the dielectric resonator element 24. In the embodiment shown in FIG.

In the embodiment shown in FIGS. 16 and 17, a penetrating hole 48 is formed at the height of the dielectric resonator element 24 and at a position that does not pass through the center, and the tuning unit is inserted into the hole 48. 30 is movably disposed within the hole 48.

In the embodiments shown in FIGS. 18 and 19, the dielectric resonator element 24 is located at a position offset from the center of the dielectric resonator element 24.
A hole 58 is formed from the upper end of 4, and 1
tuning units 30 are arranged. and,
A shaft 60 is eccentrically fixed to the tuning unit 30 and extends in the axial direction of the dielectric resonator element 24 . Therefore, when the shaft 60 is rotated, the tuning unit 30 is displaced with respect to the radial direction of the dielectric resonator element 24.

In the above-described embodiments, the dielectric resonator was configured as a cylindrical or cylindrical shape as a whole, and a TEo+a mode dielectric resonator was configured. However, a hollow angular dielectric resonator element or case may also be used. In this case, the mode would be a variant of TEo+s.

Further, in the above embodiment, a rack and a pinion are used, but this may be a simple friction mechanism.

[Brief explanation of the drawing]

FIG. 1 is an illustrative cross-sectional view showing one embodiment of the present invention. FIG. 2 is a top view of the embodiment of FIG. 1 with the top cover removed. FIG. 3 is a perspective view of essential parts showing the displacement mechanism of the tuning unit. FIG. 4 shows a sectional view of a main part for explaining the displacement according to FIG. 3. FIG. 5 is a diagram showing the state of energy distribution of the dielectric resonator element. 6 to 19 are illustrative views showing different embodiments or modifications of the present invention, respectively. In the figure, 12 is a case, 24 is a dielectric resonator element,
30 is a tuning unit, 34 and 36 are guides, and 42 and 60 are rotating shafts. Patent applicant Murata Manufacturing Co., Ltd. Agent Patent attorney Yama 1) Yoshito (and 1 other person) Engraving of the drawings (no changes to the content) Figure 16 Procedural amendments Working side June 11, 1985

Claims (1)

[Scope of Claims] 1. A conductor case, a dielectric resonator element fixed within the conductor case, a tuning unit made of a dielectric combined with the dielectric resonator element, and a tuning unit that is connected to the dielectric resonator. A dielectric resonator comprising displacement means for radially displacing the element. 2. The displacement means extends from the tuning unit in the radial direction of the dielectric resonator element, and includes a displacement axis in which the tuning unit is displaced by being displaced in the radial direction. The dielectric resonator according to item 1. 3. The dielectric resonator according to claim 2, wherein the displacement means includes a moving means for moving the displacement shaft in the radial direction. 4. The dielectric resonator according to claim 3, wherein the moving means includes a rotation shaft and a coupling means for coupling the displacement shaft and the rotation shaft. 5. The dielectric resonator according to claim 4, wherein the coupling means includes friction means. 6. The dielectric resonator according to claim 4, wherein the coupling means includes gear means. 7. The gear means includes a rack formed on the displacement shaft;
7. The dielectric resonator according to claim 6, further comprising a pinion formed on the rotating shaft and meshed with the rack. 8. Claims 2 to 7, wherein the tuning unit includes two tuning units facing each other in the radial direction, and each tuning unit is formed with a hole for receiving the displacement shaft of the other one.
The dielectric resonator according to any of paragraphs. 9. The dielectric resonator according to claim 1, wherein the displacement means includes an eccentric rotating shaft extending from the tuning unit in the axial direction of the dielectric resonator element. 10. The dielectric resonator according to claim 1, wherein the tuning unit includes a plurality of tuning units. 11. The dielectric resonator according to claim 10, wherein the plurality of tuning units are arranged radially in the radial direction. 12. The dielectric resonator according to claim 10 or 11, wherein the plurality of tuning units are arranged at different levels in the axial direction of the dielectric resonator element.