JPS5963802A - Dielectric resonator - Google Patents

Abstract

PURPOSE:To make the coefficients of linear expansion of a cylindrical dielectric body and a case arranging said dielectric body coincide with each other and to improve the temperature characteristics of resonance frequency by forming the cylindrical dielectric body constituting a dielectric resonator and at least a part of the case by the same dielectric material. CONSTITUTION:A resonator body part 13 is equipped with a dielectric case side part 14 and a dielectric cylindrical part 15 arranged concentrically in a cave 17 formed by the side part 14 and unitedly coupled by four cupling parts 16. A conductive film 18 is formed on the whole external surface of the side part 14. Conductive films 19, 20 are also formed on the lower surface of an upper cover 11 and the upper surface of a lower cover, and when these covers are set up, shielding and a real current path corresponding to an ordinary metallic case are formed by the films 18-20. Since the cylindrical dielectric body and the case are constituted by the same material, the coefficients of linear expansion of both parts coincide with each other and a minute gap between the end surface of the dielectric body and the case is removed or uniformed constantly. Thus, the temperature characteristics of resonance frequency are extremely improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dielectric resonator using the T M's + o mode of electromagnetic waves or a modified mode thereof, and particularly relates to improving the 18i degree characteristic of the resonant frequency of the dielectric resonator.

FIGS. 1 and 2 are diagrams showing an example of a dielectric resonator using the conventional Mo+o mode, which is the cost of this optical cutting. FIG. 1 is a side cross-sectional view of the resonator, and No. 20 is a plan cross-sectional view along the line t] in FIG. Referring to FIGS. 1 and 2, a dielectric resonator 1 includes a cylindrical dielectric 4 having a length L placed in a circular cavity 3 in a case 2 made entirely of metal. has been done. And TM
The electromagnetic field distribution of o+0 mode is shown, and the solid line arrow 5
are electric lines of force, and dotted arrows 6 are lines of magnetic force.

In TMo+o mode, as shown in Figs. 1 and 2,
This is the shade in which the electric field is most often concentrated inside the dielectric cylinder 4, and the resonator 1 can be made smaller. In this case, the dielectric 4 is TM.

, it works effectively for the 0 mode and is not effective for other modes, and therefore has good spurious characteristics. Moreover, this − mode has its resonant frequency to, (=C/λ0
．． Here, C: speed of light, λ0: resonance wavelength) is the resonance Ia length (
Cylindrical dielectric material) Not related to L. Therefore, the dielectric resonator can be further downsized.

In this way, the dielectric resonator using the TMO+o mode (its modified mode is also 4M) has various advantages and can be effectively used as a filter or an R-oscillation element.

However, the conventional TMo, -++ mode electric resonator has a major drawback in that the temperature characteristics of the resonance frequency are not good. That is, assuming that the humidity characteristic of the resonance frequency is 9 times, 4B'...(1) ηf → -Cy) E-α, -α2. Here, ηE: Temperature characteristic of dielectric constant α,: Coefficient of linear expansion of the galvanic body α2: Coefficient of linear expansion of the metal case A, B, C: Constants. In other words, the temperature characteristic of the resonance frequency is related to the temperature characteristic η2 of the dielectric constant, as well as the coefficients of linear expansion α1 and α2 of the dielectric material and the metal case, respectively.

Therefore, in order to improve the force characteristic ηf of the resonance frequency, in addition to selecting η5 determined by the dielectric material, α,
It is necessary to appropriately control α2 and α2. However, due to their nature, α and α2 are appropriately controlled at the same time.
1 is difficult. As a result, the temperature characteristics of the resonance frequency were also not good.

From another perspective, this means that in a conventional resonator in which the columnar dielectric 4 is disposed within the metal case 2, the dielectric 4. Due to the difference in linear expansion coefficient of each metal case 2, the small gear 17 between the columnar dielectric end face 4a and the metal case 7 facing it changes depending on the temperature change around the resonator 1. The change in the gap that occurs in this connection portion causes a change in current, and the effective dielectric constant changes.

This causes a change in C'(fo=1/2πf]d-c), which is an element that determines the resonant frequency ro.Therefore, in the conventional case, linear expansion of the case and dielectric Perhaps because of the difference in rate, there was a drawback in that the resonant frequency changed significantly with temperature.

An object of the present invention is to form at least part of the columnar dielectric that constitutes the dielectric resonator and the case in which it is arranged from the same dielectric material, so that the linear expansion coefficients of the two are matched, and the temperature characteristics of the u1 resonance frequency are adjusted. An object of the present invention is to provide a good dielectric resonator.

The present invention can be easily realized by, for example, a dielectric resonator in which a columnar dielectric and at least a part of a case are integrally formed of the same dielectric material, and a conductive film is provided on the outer surface of at least a part of the case. It is.

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

FIGS. 3 to 5 are diagrams showing an embodiment of the present invention. tts Figure 3 is a perspective view of the dielectric resonator, Figure 4 is a plan view of the dielectric resonator main body 13 excluding the upper cover 11 and lower cover 12 in Figure 3, and Figure 5 is a diagram for convenience. Line V in Figure 4
, -V is a □ side cross-sectional view.

- Referring to FIGS. 3 to 5, the dielectric resonator 10 is composed of a resonator body 13, an upper cover 11, and a lower cover 12. A cavity 17 formed by the main body part 13, the dielectric case side part 14, and this case side 6!114.
and a dielectric cylindrical part 15 concentrically arranged, and these are connected by four connecting parts 16 and integrated. Thus, the main body portion 13 includes a case side portion 14 and a cylindrical portion 15 that are simultaneously and integrally molded from the same dielectric material. This is one of '+FIm' in this example. In addition, the dielectric case side portion 14 of the main body portion 13
A conductive film 18 is provided over the entire outer circumferential surface of. Further, on the lower surface of the upper lid 11 and the upper surface of the lower [12], 6
Conductive film 19. ．． 20 is being crotched.

Then, with each lid on, these conductive films were placed at 19° and 20°.
A shield and an actual current path corresponding to a conventional metal case are formed by the conductive film 18 on the circumferential surface of the main body 13.

Note a3: In this embodiment, the conductive films 19 and 20 are provided on the lower surface of the upper lid 11 and the main surface of the lower lid 12;
A conductive film may be provided on the upper surface, side surfaces, and the lower surface and side surfaces of the lower lid 12. That is, the main body 13 and ill, 1
2, if the structure is such that the dielectric columnar part 15 is confined by each conductive film, J: Yes. Note that the conductive film 18 of the dielectric case side part 14 may be formed on the inner wall thereof, but in that case, since there is the connecting part 16, the conductive film 1+9 becomes discontinuous and electromagnetic waves leak from there. It's not practical.

As a result of the above, the dielectric cylindrical portion 15 and η = −Cη −α ・
・・・ (2・)! ! →2(1/2)η −α <−, −C→1/2). Therefore, the slope can be determined by simply controlling the coefficient of linear expansion α after selecting the electric material and determining η. This is relatively easy. That is, the temperature characteristic η of the resonant frequency can be uniquely improved only by selecting the dielectric material 4. Incidentally, C=1/2 is established when 100 paren1~resonance energy is confined within a 1 mm cylinder.

Further, in this embodiment, the dielectric case side portion 14 and the dielectric cylindrical i'ill 15 are connected to four connections 61+16.
However, the connections 61S 18 may be, for example, two in symmetric diagonal, or one, or other.

However, the connecting part 16 does not need to be continuous in the lengthwise direction and formed at both ends of the cylindrical parts 1 and 5, and may be formed only in a part of the lengthwise direction.

It is integrated with the dielectric columnar part 15.
At least a part of the case (consisting of the L lid, lower lid, and side parts) is not limited to the dielectric case side part 14, but for example, the dielectric cylindrical part 15, the lower lid, etc. It is integrated (mayoi).

In the above embodiment, as shown in FIG.
+ 15 and [), but it is limited to <r <, l words, flat cavity, Ge, -su and Bfg
q-body prismatic rectangular columnar shape 6] 1 hollow case and dielectric cylindrical part,
It may also be a combination of a circular hollow case and a dielectric square cut portion.

In this way, by deforming the shape of the columnar part of the case, a deformable mode having the same resonance frequency as the electromagnetic field distribution of 1 is obtained for M TIVjo 1o mode 1:.

(In the actual flow example, which is not shown in FIGS. 3 to 5, the T
A Mo 1o modified Sagi-do is used. ) In this embodiment shown in FIGS. 3 and 4, two small through holes 21 are formed in the axial direction of the dielectric cylindrical portion 15. This hole is for adjusting the resonant frequency to of the resonator 10 fFl. In this hole 21, the columnar part 15 is the same or IA.
By inserting a dielectric material with a dielectric constant of -jip, the resonant frequency, ri, can be changed depending on the insertion ratio.

In addition, the hole 22 formed in the upper lid 11 of Fig.
\Togi is a hole for applying a connector.

FIG. 6 111 Preferred embodiment of this invention and its own 7-/
Router μ-Example 8 Not shown Cross-sectional diagram 9 Figure 'r''''a・! Referring to FIG. 6, the dielectric resonator 10 has an exterior case 31.

It is placed inside and sealed by the exterior 32. ”
Two holes (3, 84) are formed in the outer cap 32, and coaxial type input connectors 35 and output connectors 3 and 6 are connected to these holes 33 and 34. 2 ctors
From 35 and 36, the same J1i4! in the outer case 31! l
An excitation rod 37 is inserted through the hole 22 of the resonator into the i1''O.
stands out. Excitation 4i137 and hole 33 of outer cover 32.
34 and the hole 22 of the resonator 10.
The rod 37 and the resonator 10 are coupled:
A predetermined frequency input from the input/coupler connector 35
□Only the signal of number r (baka connector 36) j
I'm afraid it will happen.

Outside, the bottom of the test case 31 is the spring 38 b” rlQ
This spring 38 causes the resonator 10 to spring 1. -, supporting. Outside fill of exterior case 31
As soon as the resonator 10 is removed from the external 1ffit! Due to the change in i, the exterior cooler 331 expands and contracts, and the spring 3a':
This keeps the vibrator 10 stable. Also, a cushion 39 made of Fell F or the like is provided on the inner surface of the outer case 31 to prevent internal resonance. The vibration chamber of the resonator 101, m 4 is reduced. , □ Roughly speaking, the conductive film 19 of the resonator 19 and the outer cover '32 are connected to the outer conductor (not shown) of the connector 35.3'6. They are electrically connected to each other by a ground plate 40.

As described above, in this invention, since the columnar M electric body and the case are made of the same material, the linear expansion coefficients of both sides are the same, and the distance between the end face of the IN body and the case surface facing the Imitation・′
There is no small gi 1/tsubu or it is always constant. Therefore, 4. the temperature characteristics of the resonant frequency of the resonator are very good. In addition, since at least a portion of the columnar electric binding body and the case are integrally connected, the relative position 11 between the columnar electric body and the case does not change mechanically or mechanically. It is stable.

[Brief explanation of the drawing]

FIG. 1 shows a side cross-section of a dielectric resonator using the conventional TMo+o mode. Figure 2 shows the line I-1 of the resonator in Figure 1.
FIG. FIG. 3 is a perspective view of an embodiment of the present invention. Figure 4 is a plane view of the main body of the resonator, excluding the upper mold and lower cover shown in Figure 3! FIG. 5 is a sectional view taken along the line V--V in the m< figure. 61st! It is a side view of a one-stage dielectric filter using one embodiment of the present invention.

Claims (1)

[Claims] In a dielectric resonator using a TMG+0 mode or a modified mode thereof, which is constructed by arranging a columnar dielectric in a case, the columnar dielectric and at least a part of the case are made of the same dielectric material. A dielectric resonator which is integrally formed and has a conductive W1 film provided on at least a part of the outer surface of the case. .