JPS5881304A - Dielectric resonator - Google Patents

Abstract

PURPOSE:To obtain a small-sized, low-priced dielectric resonator which has high operation stability by providing a conductor at a position selected depending upon the plate thickness of an insulator near a dielectric resonator element, and setting its resonance frequency to a desired value. CONSTITUTION:An insulating plate 7 is made of an insulator having a low dielectric constant than a dielectric resonator element 1, and has a conductor layer formed on one surface by vapor deposition, plating, etc. The amount of electromagnetic energy leaking out of the element 1 is controlled by shifting the closely-provided conductor layer 8 in position, and thus the resonance frequency is set to a desired value, so the desired frequency is obtained while observed, thereby placing the insulating plate 7 which is adequately thick on the element 1. The insulating plate 7 thick enough to obtain the desired characteristics is selected and fitted on the element 1 with an adhesive, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dielectric resonator that is small, inexpensive, and has high stability.

Conventionally, when using a dielectric resonator circuit by electromagnetically coupling a dielectric resonator element to a distributed constant circuit such as a microstrip line, as shown in FIG. The substrate 13 is fixed on the support stand 12 of
It was electromagnetically coupled to the strip line 14 provided above. The approximate resonant frequency of this dielectric resonator circuit is determined by the dielectric constant and geometric dimensions of the dielectric resonator element 11, but since this dielectric resonator element 11 does not have a frequency variable function, the resonant frequency Fine adjustment was performed by setting the dimensions of the metal case 15, which has an electromagnetic field shielding effect, to an appropriate value and by varying the frequency adjustment screw 16. For this reason, it is necessary to provide a metal case 15 around the dielectric resonator element 11, which has the drawback of increasing the size of the resonator circuit. Furthermore, high dimensional accuracy is required to keep the central axes of the screw 16 and the dielectric resonator element 11 within a predetermined dimension, which has the disadvantage of increasing manufacturing costs. Further, if the dimensions of the metal case 215 are not set to appropriate values, an unnecessary mode will occur and desired electrical characteristics cannot be obtained. Furthermore, this dielectric resonator circuit has the disadvantage that the resonant frequency changes with temperature due to thermal expansion of the metal case 15.

The present invention has been made in view of the above-mentioned conventional drawbacks,
The purpose is to provide a dielectric resonator that is small, inexpensive, and has high operational stability.

The details of the present invention will be explained below with reference to Examples.

FIG. 2 is a perspective view showing the configuration of an embodiment of the dielectric resonator of the present invention, in which 1 is a dielectric resonator element, 7 is an insulating plate, and 8 is a dielectric resonator element.
is a conductor layer formed on this insulating plate 7. The dielectric resonator element 1 is composed of a lump of ceramic such as barium titanate having a relatively large dielectric constant of about 40 to 100. The dielectric constant and geometric dimensions of the element 1 are determines the approximate resonant frequency of this dielectric resonator.

The insulating plate 7 has a low dielectric constant, such as 5-ohm, as well as the dielectric resonator element 1. Composed of all the best things? Finally, it is fixed to the upper surface of the element 1 via a bonding layer such as adhesive or low melting point glass. A conductor layer 8 is formed on the surface of the insulating plate 70 by an appropriate method such as vapor deposition or plating. An example of a method for forming the conductor layer 8 is to first deposit a layer of 200 Å thick on the surface of the insulating plate 7.
A nichrome layer of about (20+%I@) is vacuum-deposited, then an Am layer of about 500 mm thick and Z is vapor-deposited on top of this, and finally an Am layer of about 5 pwm thick is electrolytically plated on top of this.
It forms a layer. Note that the nichrome layer in this case functions as a base to increase the adhesion strength between the conductor layer 8 and the insulating plate 7, and the thickness of this layer is kept as small as possible to prevent a decrease in the Q of the resonator. is set to

In the dielectric resonator configured in this manner, the resonant frequency is approximately determined by the dielectric constant and geometric dimensions of the dielectric resonator element 1. At this time, most of the electromagnetic energy exists inside the dielectric resonator element 1 having a high dielectric constant, but a part of it leaks to the outside of the dielectric resonator element 10. The amount of electromagnetic energy leaking to the outside can be controlled by placing a conductor layer 8 near the dielectric resonator element 1 and changing the position of the conductor layer 8. The conductor layer 8 is for controlling the leakage of electromagnetic energy, and the insulating plate 7 having a predetermined thickness functions as a spacer for holding the conductor layer 8 at a predetermined distance from the element 1. . As the material for the insulating plate 7, a material with low high frequency loss such as quartz is desirable in order to increase the Q of this dielectric resonator. Since the amount of electromagnetic energy leaking to the outside of the dielectric resonator element 1 depends on the thickness of the insulating plate 7, that is, the position of the conductor layer 8, in the dielectric resonator configured as shown in FIG. This can be adjusted by changing the thickness of the insulating plate 7 provided with the conductor layer 8.

Specifically, several types of insulating plates 7 with different thicknesses are prepared, and while observing the resonant frequency of the dielectric resonator in the circuit shown in FIG. 7 is placed on the dielectric resonator element 1, and after selecting an insulating plate 7 having a thickness that provides the desired characteristics, this is attached onto the element 1 using adhesive or the like.
Stepwise surface resonance frequency adjustment corresponding to the thickness of the insulating plate 7 can be performed. By preparing the insulating plates 7 with a large number of thicknesses, the resonant frequency can be adjusted almost continuously. In this embodiment, the cross-sectional shapes of the dielectric resonator element 1 and the insulating plate 7 are circular, but the same effects can be obtained even with other shapes.

FIG. 4 is a perspective view showing the structure of another embodiment of the present invention. Elements in this figure with the same reference numerals as those in FIG. 2 are the same elements as those already described in connection with FIG. 2, and no redundant explanation will be necessary. In this embodiment, the conductor layer 8 is not formed over the entire surface of the insulating plate 7 but only around its periphery. The amount of electromagnetic energy leaking to the outside of the dielectric resonator element 1 depends on the area of the conductor layer 8. Therefore, by incorporating this resonator into a circuit as shown in Figure 5 and removing an appropriate area of the conductor layer 8 by laser triangulation while observing the electrical characteristics, a dielectric resonator can be formed corresponding to that area. The amount of electromagnetic energy leaking to the outside from the element 1 can be adjusted, and as a result, the resonant frequency of this dielectric resonator can be set to a desired value. In this embodiment, the removed portion of the conductor layer 8 is circular, but other shapes can provide similar effects and effects.

FIG. 6 shows a specific example of resonant frequency adjustment when the dielectric resonator circuit shown in FIG. 3 is constructed using the dielectric resonator shown in FIG. 2. The resonant frequency varies in frequency by approximately 10-. In addition, Figure 6 shows the dimensions of the dielectric resonator element with a diameter of 7.
This is an example in which the thickness is 2.8 mm, quartz is used as the insulating plate, and the zero dimension is 11 sam in diameter.

In FIG. 7, the voltage decreases when the dielectric resonator circuit shown in FIG. 5 is constructed using the dielectric resonator shown in FIG. 4. In addition, Figure 7 shows the dimensions of the dielectric resonator element with a diameter of 7 mm.
, thickness is 2.8 mm, quartz is used as the insulating plate 7, and its dimensions are 7++ atm in diameter and 0.5 atm in thickness. - This is an example when it is set as 1'1.

In the above embodiment, an insulating plate was attached to the top surface of the dielectric resonator element, but since the electromagnetic energy leaking around this element is almost isotropic, the surface to which the insulating plate should be attached is as described above. It is not limited to the top surface, but may be the side surface, or both the top surface and the side surface. Further, when the dielectric resonator element is hung and held, an insulating plate can be attached to the lower surface of the element.

In addition, although we have explained an example of using quartz as an insulating plate, if it is a dielectric material with low loss and low permittivity, suitable materials such as tetrafluoroethylene or ceramic, which are commercially available under trade names such as Teflon, may be used. can be used.

As explained in detail above, the present invention provides a conductor with a selected area at a position selected by the thickness of the insulator near the dielectric resonator element. The structure adjusts the amount of leaking electromagnetic energy and thereby sets the resonant frequency of the dielectric resonator to a desired value, so there is no need for a metal case or frequency adjustment screws as in conventional dielectric resonant circuits. As a result, it is possible to downsize the circuit and reduce manufacturing costs. In addition, there is no problem of unnecessary modes occurring due to inappropriate dimensions of the metal case, and there is no change in operating characteristics due to thermal expansion of the metal case, resulting in extremely improved stability. be.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the configuration of a conventional dielectric resonator circuit, FIG. 2 is a perspective view showing an embodiment of the dielectric resonator according to the present invention, and FIG. 3 is a dielectric resonator circuit shown in FIG. FIG. 4 is a cross-sectional view showing an example of the configuration of a dielectric resonator circuit using a body resonator, FIG. 4 is a perspective view showing another embodiment of the dielectric resonator of the present invention, and FIG. A cross-sectional view showing an example of the configuration of a dielectric resonant circuit using a resonator, FIG. 6 is a characteristic diagram showing an example of the Q characteristics of the resonant circuit shown in FIG. 3, and FIG. A characteristic diagram showing an example. 1.11... Dielectric resonator element, 7... Insulator plate, 8... Conductor layer, 12... Insulator support base, 13...
...Substrate, 14...Microstrip line, 15
...Metal case, 16...Screw for frequency fine adjustment. Patent applicant Nippon Telegraph and Telephone Public Corporation Figure 1 Figure 21121 Figure 3 Figure 4 Figure 5 Figure 61 Thickness of insulating plate (mm) No. 7111 Diameter of conductor removed portion (mm) 16-

Claims (1)

[Claims] A dielectric resonator comprising a dielectric resonator element that is electromagnetically coupled to a distributed constant circuit to impart resonance characteristics to the distributed constant circuit, the dielectric resonator element comprising: an insulator; A conductor layer having a predetermined area is formed on at least a part of the surface of the plate opposite to the surface in contact with the dielectric resonator element,
and the predetermined thickness of the insulating plate and the predetermined area of the conductor layer are selected to determine the resonant frequency of the dielectric resonator together with the dielectric constant and dimensions of the dielectric resonator collector. dielectric resonator.