JPS6160601B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coaxial dielectric resonator, and provides a coaxial dielectric resonator that is small in size, has excellent vibration resistance characteristics, and has little manufacturing variation.

Conventionally, as a coaxial resonator, there is a resonator configured with a λ/4 or λ/2 coaxial line whose wavelength is short-circuited using a high dielectric constant material. These resonators have the disadvantage that high-order spurious resonances appear prominently at integral multiple frequencies. In order to improve this, conventionally the first
As shown in the figure, an attempt has been made to provide dielectric materials 3 and 4 with different dielectric constants between the outer conductor 2 and the inner conductor 1 in a 1/2 resonator, but such a configuration is not practical. When assembling a resonator, the adhesion and fixing of different dielectrics to each other becomes uncertain, and there are also disadvantages when adjusting the resonant frequency or making the resonator more compact.

As another conventional example, as shown in FIG. 2, a center conductor 5 is formed in a cylindrical outer conductor 6 with one end open and the other end short-circuited, and a dielectric material 4 is mounted on a part of the open end side. Things are being thought of. Although this method largely solves the above problems, actual assembly requires consideration of variations and requires considerable machining accuracy of the material. In other words, since a dielectric material is inserted between the inner and outer conductors, a small gap is created between the conductor wall surface and the material, which has a large effect on the resonant frequency and also makes the vibration resistance and temperature characteristics unstable. Make it. The present invention provides a resonator that eliminates these various drawbacks, and further provides a resonator that is advantageous in terms of miniaturization and high Q.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. 3 and 4 show an embodiment of the present invention, in which a dielectric material 3 having the shape shown in FIG.
A dielectric material 4 having the shape shown in FIG. 4 is separately prepared. These can be easily mass-produced by press forming and sintering. Then, the dielectric material 3 shown in FIG.
The dielectric material 4 shown in FIG. 4 is fitted into the convex portion 7 of the dielectric material 4. At that time, a silver paste or the like is applied to the inner peripheral surface of the dielectric material 4 to form a conductive layer 8.
A conductor layer 9 is provided on the surface of the convex portion 7 of the dielectric material 3 in contact with the convex portion 7 by performing similar treatment. Figures 3 and 4
FIG. 5 shows the structure of the resonator of the present invention in which the two dielectric materials 3 and 4 shown in the figure are fitted together. In this case, after fitting dielectric materials 3 and 4, dielectric material 3
An outer conductor coating is formed on the outer periphery of the outer conductor 10 and 4.
Then, an inner conductor coating is formed on the inner peripheral surface of the dielectric material 3 to form an inner conductor 11, and a conductor coating 12 is further formed on one end surface to connect the outer conductor coating 10 and the inner conductor coating 11. A conductor film 1 is provided to connect the inner conductor film 11 and the conductor layer 8 or 9.
form 3. Silver paste or the like is used for these conductor coatings, and after application, baking is performed in a high temperature furnace to form a conductor coating with good electrical conductivity. The gap between the dielectric material 3 and the dielectric material 4, which are in contact with each other through the conductor layers 8 and 9, may be several times the skin depth or more, and is usually about 20 μm to 100 μm. In this case, there is an advantage that not only is assembly easy, but also there is no variation in resonance frequency since the conductor is filled between the dielectric materials 3 and 4. Another advantage is that the two dielectric materials are firmly bonded and fixed.

Furthermore, as shown in FIG. 5, this resonator uses conductor layers 8 and 9 to bond dielectric material 3 and dielectric material 4, resulting in a double coaxial resonator. A greater reduction in size than the conventional resonator shown in FIG. 1 is achieved. Further, since the space can be utilized to the maximum, there is little deterioration in Q. As the dielectric material 3, it is preferable to use a material that has as little dielectric loss as possible even if the dielectric constant is low. Cheap and stable materials such as alumina and forsterite are suitable. on the other hand,
As the dielectric material 4, the volume used is small,
In order to achieve miniaturization, a material having a dielectric constant equal to or higher than that of the dielectric material 3 is suitable. The resonance condition is given by Equation 1.

K ₃ = tanβ ₁ l ₁ + (K ₂・sinβ ₁ l ₂ /cosβl ₁ )・tanβ ₃ l ₃ …(1) However, β: Phase constant β=2πo√ _r1 /c β=2πo√ _r2 /c (o: resonance frequency, c: speed of light) Here, the relative permittivity of the dielectric materials 3 and 4 is ε _r1 ,
ε _r2 , the inner conductor radius of dielectric material 3 is γa, the inner conductor radius of dielectric material 4 is γb ₁ , and the outer conductor radius is γb.
It is said that

According to this, for example, if forsterite (εr=6) is used as the dielectric material 3 and a high permittivity material (εr=85) is used as the dielectric material 4, the resonator length can be reduced to 1/10 or less. can do.

FIG. 4 shows another embodiment of the present invention, in which the dielectric material 4 is made longer by Δl, and by changing this part by polishing or the like,
The resonant frequency can be adjusted even after the resonator has been baked with high-temperature silver.

As described above, according to the present invention, a small, high-Q resonator free of integer multiple higher-order spurious can be constructed with good reproducibility and by an easy assembly method. The present invention realizes a double coaxial resonator, which has excellent performance but has a slightly complicated structure, at the same time as the effect of adhesion and fixation of two types of dielectric materials, and extremely useful resonance. It provides equipment.

In the above embodiment, it is assumed that the cross section perpendicular to the axis is circular, but it goes without saying that the same effect can be obtained even if the cross section is rectangular.

The resonator according to the present invention can be used in all kinds of telecommunication equipment. In particular, in response to the recent trend of miniaturization of equipment, it is applied to filters, oscillators, etc., and is expected to be effective in mass production, making it extremely useful industrially.

[Brief explanation of the drawing]

Figures 1 and 2a are vertical cross-sectional views of a conventional coaxial dielectric resonator, Figures 2b and 4a are cross-sectional views of the same, and Figures 3 and 4a are views of the coaxial dielectric resonator of the present invention. A vertical cross-sectional view of the parts used, b is a cross-sectional view of the same, No.
Figure A is a longitudinal cross-sectional view of a dielectric resonator according to a first embodiment of the present invention, Figure B is a cross-sectional view thereof, and Figure 6 is a vertical cross-sectional view showing another embodiment of the present invention. 3, 4... Dielectric material, 8, 9... Conductor layer, 1
0... Outer conductor, 11... Inner conductor, 12, 13...
conductor coating.

Claims (1)

[Claims] 1. An open end of a first dielectric material having an inner conductor has a protrusion, and a ring-shaped second material is fitted into the protrusion through a conductor layer. A dielectric material is provided, an outer conductor is formed on the outer periphery of the first and second dielectric materials, and the outer conductor and the inner conductor are connected by a conductor coating provided on the shorted end surface, Furthermore, the coaxial dielectric resonator is characterized in that the conductor layer and the inner conductor are connected by a conductor coating provided on the open end surface. 2 The protrusion of the first dielectric material and the ring-shaped second
The coaxial according to claim 1, wherein the conductive layer provided at the fitting portion with the inner circumferential surface of the dielectric material is formed of a good conductor such as silver paste which is sufficiently thicker than the skin depth. type dielectric resonator. 3. Claims 1 or 2, characterized in that the dielectric constant of the second dielectric material is equal to or greater than that of the first dielectric material. Coaxial dielectric resonator. 4. Coaxial dielectric resonance according to claim 1 or 2, characterized in that the axial end face of the second dielectric material projects from the open end face of the first dielectric material. vessel.