JPS5997201A - Resonance circuit device - Google Patents

Abstract

PURPOSE:To facilitate the adjustment of the temperature dependence of a resonance frequency by providing two kinds of dielectric bars different in temperature dependence of dielectric constant in through holes of a dielectric substrate and a vessel. CONSTITUTION:A through hole 7 is provided in a dielectric substrate 2 and a vessel 3. Dielectric bars 4 and 5 which have one ends fixed to an adjusting screw 6 and are different in temperature dependence of dielectric constant from each other are provided in the through hole 7 and a through hole 8 of a dielectric resonator 1. Thus, the screw 6 is adjusted to change the positional relation, thereby adjusting the temperature dependence of the resonance frequency easily.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resonant circuit device having a dielectric resonator suitable for microwave circuits. In particular, the present invention relates to a resonant circuit device that can easily adjust the temperature dependence of resonant frequency.

A dielectric resonator made of a dielectric material with low loss and high dielectric constant in the microwave band has a high no-load Q value, is small, and has good temperature dependence of the resonant frequency. It is particularly suitable for microwave resonant circuits that require high temperature stability. The temperature dependence of the resonant frequency of the dielectric resonator is determined by the temperature dependence of the dielectric constant of the resonator material and the volume change due to thermal expansion. In recent years, dielectric resonators having a positive or negative temperature coefficient in which the temperature dependence of the resonant frequency is precisely controlled have been commercially available.

On the other hand, the resonant frequency of a resonant circuit (hereinafter simply referred to as a resonant circuit) composed of a dielectric resonator (hereinafter simply referred to as a resonator) and a coupled line is determined by the degree of coupling between the resonator and the coupled line or the resonator. It varies depending on factors such as the positional relationship between the conductor and the surrounding conductor. Therefore, the temperature dependence of the resonant frequency also depends on the temperature dependence of the coupled line circuit parameters, the positional relationship between the resonator and the surrounding conductors, and the like. In particular, when a semiconductor element is included in a coupled line system, such as in an oscillator, the amount of temperature change in the coupled line system circuit parameters due to the temperature change in the semiconductor element characteristics is large, and the temperature dependence of the resonant frequency of the resonant circuit is large. On the other hand, the influence of the coupled line system cannot be ignored.

Therefore, in order to increase the temperature stability of the resonance frequency of the resonant circuit, there is a method of using a resonator with a temperature coefficient opposite to that of the coupled line system to offset the temperature dependence of both, or a method of canceling the temperature dependence of the two, or changing the degree of coupling between the resonator and the coupled circuit. A method has been adopted to reduce the influence of the coupling circuit system on the resonant frequency as much as possible by reducing the .

However, the former method has the disadvantage that it is extremely susceptible to variations in temperature characteristics of the resonator or coupling circuit system, and is not suitable for mass production. In addition, the latter method has circuit constraints in reducing the degree of coupling, and also requires highly accurate reproducibility in the temperature dependence of the resonant frequency, as it is subject to variations in the temperature characteristics of the resonator body. It is insufficient for certain cases.

For the above reasons, in order to set the resonant frequency temperature dependence of a resonant circuit with high precision and good reproducibility, a method of adjusting the hybrid characteristic variations of the resonator and coupled line system is required1. In order to adjust the temperature characteristics mentioned above, a method is used in which a metal layer such as an adjustment screw is placed near the resonator and the change in resonance frequency temperature characteristics is utilized by changing the positional relationship between the adjustment metal conductor and the resonator. It is being However, the above-mentioned conventional method has a drawback that, by changing the positional relationship between the adjustment metal conductor and the resonator, the temperature characteristics of the resonant frequency of the resonant circuit change, and at the same time, the resonant frequency also changes significantly.

If the distance between the tuning metal conductor and the resonator is increased in order to reduce the resonance frequency change, 1. 3. Adjustment range of temperature characteristics is small and not suitable for practical use. Further, although it is possible to readjust the change in the resonant frequency by some other means, the temperature characteristics of the resonant frequency also change again, which makes the adjustment work extremely complicated and increases the number of shears, so there is little advantage.

An object of the present invention is to provide a resonant circuit using a dielectric resonator in which the temperature dependence of the resonant frequency can be easily adjusted without changing the resonant frequency.

The present invention relates to a dielectric resonator having a through hole, a lightning arrester and a body bar inserted into the dielectric resonator through hole and made of two types of dielectric materials having different temperature dependencies, and It is characterized by having means for adjusting the positional relationship between the body resonator and the dielectric rod.

Hereinafter, the present invention will be explained in detail using the drawings. 1st
The figure shows a cross-sectional view of an embodiment of an integrated microwave circuit to which the present invention is applied. A cylindrical dielectric resonator 1 having a cylindrical through hole 8 is fixed with an adhesive or the like on the surface of a dielectric substrate 2 which is fixed by soldering onto a ground conductor 3 forming a container. 1. A through hole 7 is provided in the dielectric substrate and the container 3, and the through hole 7 and the dielectric resonator through hole 8 are connected to each other.
Inside is located a dielectric rod, one end of which is fixed to the adjustment screw 6 using adhesive or the like. The dielectric rod is formed by fixing dielectric rods 4 and 5 whose dielectric constants have different temperature dependencies with adhesive or the like. Further, a screw having the same diameter as the adjusting screw is formed in the container 3, and by adjusting the adjusting screw 6, the vertical positional relationship between the dielectric rods 4 and 5 and the dielectric resonator can be adjusted. Further, a microstrip line 9 is formed by a metallized layer on the surface of the dielectric substrate 2, and a resonator system (hereinafter simply referred to as a resonator) consisting of a dielectric resonator and a dielectric rod is formed at a predetermined resonant frequency. (called the organ system).

On the other hand, the temperature coefficient of the dielectric material forming the dielectric resonator can be set to any value around zero by changing its composition ratio. Further, during this period, the change in dielectric constant can be suppressed to a few inches or less. The dielectric rods 4 and 5 are made of dielectric materials having substantially the same dielectric constant and different temperature dependencies.

Generally, in a resonant circuit using a dielectric resonator, most of the electromagnetic energy exists inside the dielectric resonator and in close proximity to the resonator. Therefore, the resonant frequency in the resonant circuit shown in FIG. 1 is determined by the portions of the dielectric rods 4 and 5 in the immediate vicinity of the dielectric resonator, and the dimensions and dielectric constant of the dielectric resonator 1.

Therefore, changing the positional relationship between the dielectric resonator 1 and the dielectric rods 4 and 5 using the adjustment screw 6 changes the isometric permittivity temperature coefficient of the dielectric rod near the dielectric resonator. be equivalent to. Therefore, by adjusting the adjustment screw 6, the temperature dependence of the resonance frequency can be easily adjusted. Furthermore, since the difference in permittivity between the dielectric rods 4 and 5 is extremely small, the isometric permittivity of the dielectric rod near the dielectric resonator hardly changes in the above adjustment. Therefore, the variation in the resonant frequency that occurs during the above adjustment is extremely small and can be ignored in practice.

As described above, according to the present invention, the temperature dependence of the resonant frequency can be easily adjusted. Since the above adjustment does not cause any fluctuation in the resonance frequency, it is clear that the temperature characteristics can be adjusted much more easily than in the conventional method.

The adjustment method according to the present invention is useful for adjusting the resonant frequency temperature characteristics of an integrated microwave filter using a dielectric resonator and for adjusting the oscillation frequency temperature characteristics of an integrated microwave oscillation circuit using a dielectric resonator. It is clear that this can also be applied. Furthermore, it is clear that the adjustment method of the present invention can also be applied to r7c when a waveguide circuit using a dielectric resonator or a coaxial line is used as a coupled line.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an integrated microwave circuit device showing one embodiment of the present invention. 1... Dielectric resonator, 2... Dielectric substrate, 3... Ground conductor, 4... Dielectric rod, 5...・Dielectric rod, 6...adjustment screw,
7.8...Through hole, 9...Microstrip line.

Claims (1)

[Claims] a dielectric resonator having a through hole, a dielectric rod made of two types of dielectric materials having different temperature coefficients and the same dielectric constant inserted into the dielectric resonator through hole, and the dielectric resonance. 1. A resonant circuit device comprising means for adjusting the positional relationship between the container and the dielectric rod.