JPH03143103A - Dielectric resonator - Google Patents

Abstract

PURPOSE:To remarkably reduce the entire size of a dielectric filter formed with the combination of resonators and to reduce the loss of the filter by designing the cross sectional shape of the resonator to be rectangular in a direction orthogonally to the prolonged direction of a throughhole formed with an inner conductor of a dielectric material. CONSTITUTION:The conductor film is formed on the inner surface of a throughhole 11 to form the inner conductor. The conductor film 13 is formed to outer peripheral faces of the dielectric material 11 with no throughhole openings to form an outer conductor. A conductor film is formed also to a lower face with the throughhole opening to form a short-circuit end face short- circuiting the inner conductor and the outer conductor, while the upper face is formed to be at open end face on which the dielectric material is exposed. The cross sectional shape of the opening end surface is the rectangular as shown by the figure. That is, the length b1 of the minor side and the length b2 of the major side are made different from each other. Then even when the inner conductors of small sized resonators are closed to each other, the coupling is reduced and the miniaturization is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a dielectric resonator, and particularly to a dielectric resonator suitable for obtaining a small dielectric filter.

[Prior art]

Dielectric filters using dielectric ceramics are used in high frequency regions such as microwave bands. Conventionally, a cylindrical coaxial TEM resonator in which the inner conductor is capacitively coupled has been common, but a block-shaped dielectric filter as shown in FIG. 5 has also come to be used.

In this structure, a plurality of through holes 51 are provided in a dielectric block 50, a conductor film is formed in the through holes 51 to form an inner conductor, and a conductor film is also formed on the side surface to form an outer conductor. be. A conductive film is also formed on the surface of the lower surface of the dielectric block 50 where the opening of the through hole is located, and serves as a short-circuit end surface. The top surface of the figure is an open end surface with exposed dielectric material. The inner conductor and the outer conductor constitute a resonator unit, and through holes 52 are formed between the through holes 51 in order to adjust the coupling between the resonator units.

[Challenge] Miniaturizing such a dielectric filter to create a resonator Unino I
・It is desired to reduce the distance between the resonator units, but unless holes are formed to adjust the coupling, the coupling between the resonator units will become too large and it will be difficult to achieve the desired characteristics (?JE). .

Furthermore, when the distance between the inner conductor and the outer conductor of the droplet body becomes smaller, the covert i1 Q decreases, and the loss of the filter increases.

The present invention provides a dielectric resonator that solves these problems and allows the filter to be made smaller.

[Means to solve the problem]

The present invention solves the above-mentioned problems by making the cross-sectional shape in the direction perpendicular to the extending direction of the through hole in which the dielectric inner conductor is formed into a rectangular shape.

That is, it has a through hole extending parallel to the side surface of the dielectric,
A dielectric resonator in which an inner conductor is formed in the through hole and an outer conductor is formed on the side surface, characterized in that the cross-sectional shape of the dielectric in a direction perpendicular to the extending direction of the through hole is rectangular. It is something that you have.

Furthermore, it is characterized in that the cross-sectional shape of the dielectric and the cross-sectional shape of the through hole are substantially similar. When the similarity ratio is set to 3 to 4, the no-ft load Q can be increased.

[Effect]

By arranging the dielectric resonators in a rectangular shape along the shorter sides, the overall dimensions of the dielectric filter can be shortened.

The unloaded Q can be increased as the length in the direction perpendicular to the arrangement direction is increased.

Additionally, as a result of experiments, it was found that when the outer and inner circumferences of the dielectric are made similar in shape, the no-load Q is maximized when the ratio is set to 3 to 4.

〔Example〕

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

FIG. 1 is a perspective view showing an embodiment of the present invention. A rectangular parallelepiped dielectric ceramic fired body 10 has a through hole 11 extending from one surface to the opposite surface. This through hole 1
Inside 1, a conductive film is formed on the surface to serve as an inner conductor.

A conductor film 13 is formed on the outer peripheral surface of the dielectric 10 on which the through hole 11 is not opened, and serves as an outer conductor. A conductive film is also formed on the surface where the opening of the lower through hole is, forming a short-circuited end surface that shorts the inner conductor and the outer conductor, but the upper surface is open with exposed dielectric material. There is.

The cross-sectional shape of the open end surface is rectangular as shown in FIG. That is, the short side length bl and the long side length b2
It is different from When arranging dielectrics as a dielectric filter, it is preferable that the resonators are brought into contact with each other on the long side of length b2.

Although the shape of the through hole 11 in which the inner conductor is formed can be any shape, it is desirable that the shape be similar to the outer shape of the dielectric 10. That is, it is preferable to make the ratio of the length a1 of the short side of the through hole equal to the length a2 of the long side.

FIG. 3 shows the change in the no-load Q when the similarity ratio is changed when the outer shape of the dielectric and the through hole are formed to be similar as described above. The length of the short side shown in Figure 2,
are set to 4 mm, 7 mm, 10 mn+, and 13 mm, the length b2 of the long side is set to 1.5 times that length, the through holes are formed in similar shapes, and the values of bi/a+ (i.e. bz/az) are changed. It shows the change in the value of no-load Q.

The length of the short side of curve 36, 37, 38, 39 is 4 mm.
, 7mm, 10mm, and 13mm+. In both cases, the no-load Q value increased when b/a was 3 to 4, and reached its maximum value when b/a was 3.6. Naturally, the larger the overall dimensions, the larger the value of the no-load Q will be, but when the dimensions are made smaller, the no-load Q
The value of can be increased.

The dielectric resonator according to the present invention is capacitively coupled between inner conductors.
Although it can also be used with a dielectric material 40 as shown in FIG.
An inner conductor is formed in the through hole 41 of the resonator, and resonators with an outer conductor 43 formed on the outer peripheral surface are arranged in contact with each other, and a part of the conductor film on the contacting side surface is removed to form a cavity 44, and a cavity 44 is formed between the resonators. It is also possible to couple by capacitive coupling and =F F coupling.

By adjusting the position and area of this cavity, the bonding state can be changed. Therefore, even if the inner conductors of a small resonator are brought close to each other at LJ, the coupling can be reduced, making it easy to downsize.

〔effect〕

According to the present invention, it is possible to significantly reduce the overall size of a dielectric filter in which a resonator is combined.

Further, even if the filter is miniaturized, the no-load Q value can be maintained, so the loss as a filter can be reduced.

Moreover, it can be used not only for filters but also for dielectric resonators used in oscillators and the like that require thinning.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an embodiment of the present invention, Fig. 2 is a plan view thereof, Fig. 3 is an explanatory diagram of the relationship between dimensions and characteristics, and Fig. 4 is a perspective view showing another embodiment of the invention. , Figure 5 is a perspective view of a conventional dielectric filter. 10.40...Dielectric 11, 41...Through hole (inner conductor) 13.43...Outer conductor

Claims (4)

[Claims] (1) In a dielectric resonator that has a through hole extending parallel to the side surface of the dielectric, an inner conductor is formed in the through hole, and an outer conductor is formed on the side surface, the dielectric resonator is perpendicular to the direction in which the through hole extends. 1. A dielectric resonator, wherein the dielectric has a rectangular cross-sectional shape in a direction. (2) A dielectric resonator having a through hole extending parallel to the side surface of the dielectric, an inner conductor formed in the through hole, and an outer conductor formed on the side surface, at right angles to the direction in which the through hole extends. 1. A dielectric resonator, wherein the dielectric has a rectangular cross-sectional shape in a direction, and the cross-sectional shape of the dielectric and the cross-sectional shape of the through hole are substantially similar. (3) The cross-sectional dimension of the dielectric is 3 or more of the cross-sectional dimension of the through hole.
3. The dielectric resonator according to claim 2, wherein the dielectric resonator is four times as large. (4) The dielectric resonator according to claim 1, wherein the outer conductor is not formed on at least a portion of the side surface corresponding to the long side of the rectangle, and the dielectric material is exposed.