JPH02290302A - Coaxial type dielectric resonator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improvement in a coaxial dielectric co-imager used at high frequencies.

BACKGROUND ART FIG. 4 shows an example of a coaxial dielectric resonator using a conventionally used dielectric material. In Figure 4, a? Axial cross-sectional view, b is a cross-sectional view of a at ▲person'; in the figure, 41 is a dielectric, 42 is an internal conductor, 43 is an external conductor, and 44
is the short circuit. This co-installer has been used conventionally, has a simple structure, and has a good no-load Q value.

Problems to be Solved by the Invention The coaxial type dielectric co-installer with the structure shown in Fig. 4 has a simple structure and can obtain a good no-load Q value. (2) also has a resonance point, so when used as such a common camera or an output filter of an amplifier, it is not possible to suppress 3 times or 6 times higher harmonic components. For this reason, it is often necessary to use a band-elimination filter or a low-pass filter to remove harmonic components.

Means for Solving the Problems The present invention provides at least one step on the inner circumference of a coaxial dielectric, one side of the step is square and the other is circular, and the outer circumference of the dielectric is prismatic. It was configured as follows.

By creating at least one step on the inner periphery of the working coaxial dielectric and changing the impedance of the upper and lower parts of the dielectric in a step-like manner, unlike a resonator with uniform impedance, the spurious frequency is reduced to the fundamental frequency. It becomes possible to remove it from an integer multiple of .

Furthermore, by making the external shape a prism, the packaging density in the case is also higher than that of conventional cylindrical resonators.

Furthermore, compared to a cylinder having a cylindrical outer shape, the volume is larger even with the same diameter, so the no-load Q is also improved.

Example FIGS. 1 and 2 show an embodiment of the present invention.

Both have a structure in which a step is provided at one place on the inner periphery of a coaxial dielectric.

In FIG. 1, reference numeral 11 denotes a dielectric material which is formed in a hollow shape and whose outer shape is a square prism. The hollow portion is formed so that the cross-sectional inner circumferential shape on the side of the arrow C is circular, and the cross-sectional inner circumferential shape on the arrow C side is square. 13 is an outer conductor formed to cover the outer peripheral surface of the dielectric 11; 14 is a short-circuit conductor formed to cover one end surface of the dielectric 11; Conductor 12 and external conductor 13 are electrically connected. In addition, 16
is the edge where the dielectric material is exposed and is called an open surface.

The coaxial dielectric resonator of this embodiment configured as described above can control spurious frequencies unless the internal conductor 12 has a uniform shape as shown in FIG. Now let rb be the diameter of the internal conductor of the coaxial part with a circular inner periphery, and r be the two sides of the internal conductor of the part with a square inner periphery. , rf, and the two sides of the outer conductor are rch rd, and the impedance Z0 of the line is Z o1-(eo/tr") * where the inner periphery of the coax is circular, where the relative permittivity of the dielectric is εr. Engineering n (1.
17a ((rc + rd)/2 * rb)
) In the case where the coaxial inner periphery is square, zo2-(60/εrk)*In(ro+rd)/(r
, +ry)).

Therefore, the coaxial dielectric rb, ro, r6,
Line impedance can be changed by changing rd and rf.

In Figure 1, the impedance of the line (length l,) close to the short-circuit conductor 14 is 2.1, and the impedance of the line close to the open surface (length l2) is 2.1.
When the impedance of is zo2, the common root condition of the co-imager is tanβl1t&nβl2 = tanθ1tlLnθ2
=zo1/Zo2β: Phase constant θ1=βl1・θ2−βl2 It can be expressed as follows.

For simplicity, consider the case where l1'''2, that is, θ1=θ2=θ.The resonance condition in this case can be expressed as (tan f)zo=z01/z02=K (K: impedance ratio).Resonance Since the frequency and the electrical length θ are proportional, the resonance frequency is expressed as f.The Sderius resonance frequency is expressed as f81 1 f32 from the lowest one, and the corresponding θ
θ. , θ, 1, θ32, then ? -tan'K'51"" (θ81/θ.)*f0-((π-θ.)/
θ. )*fo= (7r/tan' K”-1)
* f'■r = (θ / θ ) * f 2 ((π + θ
. )/θ. )*ro=:(yr/tan I K1A
+ 2>*ro relationship can be changed.

That is, it can be seen that the Sderius co-mining frequency is a function of the impedance ratio K. By varying the line impedance of the coaxial dielectric resonator in this way, the spurious resonance frequency can be removed from an integral multiple of the fundamental frequency, and when applied to the output filter of an excavator or amplifier, it can be It becomes possible to realize a filter that can suppress wave components. In addition, in this example, the inner peripheral part which is a square is
Although the case where the inner circumferential portion is parallel to each side of the outer circumference has been described, the same effect can be obtained even if the inner circumferential portion is not parallel to each side of the outer circumference.

The embodiment shown in FIG. 2 can also be explained in the same way as the case of FIG.

In the embodiment shown in FIG. 2, the dielectric material 21 on the open surface 2e side is made thicker.
In this case, the inner conductor 22 has a step portion 26 and is connected to the outer conductor 23 via a shorting conductor 24 .

In the case of the embodiment shown in Fig. 2, the impedance ratio K>1 is obtained, and the line length l1 near the short circuit part in Fig. 2, the line length 7!2 near the open end, and the resonator in Fig. 3. Long! . If this is the case, the joint organ length (l1+22)>7io is obtained, which is large, but the no-load Q hardly changes, and the dimensional accuracy becomes gentle, making it easy to adjust the frequency.

FIGS. 3a and 3b are a longitudinal sectional view and a transverse sectional view showing another embodiment. In FIGS. 3a and 3b, 31 is a dielectric, 32 is an internal conductor, 33 is an external conductor, 34 is a short-circuit conductor, and 35 is a short-circuit conductor.
．． 36 is a stepped portion, and 37 is an open surface. The coaxial dielectric resonator configured in this way has a structure with two stepped portions, but like the embodiments shown in FIGS. 1 and 2, it has high mounting efficiency and can be miniaturized. Moreover, it has the effect of high no-load Q.

In this embodiment, the case where one step portion is provided and the case where two step portions are provided are explained, but the same effect can be obtained even when three or more step portions are provided.

Effects of the Invention As described above, the resonator according to the present invention not only allows the spurious resonance frequency to be set freely, but also has the following effects.

(1) High mounting efficiency and miniaturization possible.

(Less than conventional A in volume ratio) - Since it is square, there is less wasted space.

・By changing only the dimensions of one of the two sides of the square external conductor, it is possible to manufacture resonators with various characteristics at a constant width, providing a high degree of freedom in design.

(2) The no-load Q is higher than that of a cylindrical resonator with the same mounting volume.

These effects make it possible to design a resonator that takes advantage of its characteristics depending on the application, and the degree of freedom in design is significantly improved compared to conventional coaxial resonators. Moreover, since it is a common pregnancy organ with a structure that is suitable for mass production, its industrial value is extremely large.

[Brief explanation of drawings]

1a and 2a are longitudinal cross-sectional views of a coaxial dielectric resonator according to an embodiment of the present invention, and FIGS. 1b and 2b are cross-sectional views of FIGS. 1a and 2&, respectively. FIG. 3a is a vertical cross-sectional view showing another embodiment, FIG. 3b is a cross-sectional view of the same, and FIG. 4a is a cross-sectional view.
is a vertical cross-sectional view showing a conventional coaxial dielectric co-photograph; Fig. 4b
is a cross-sectional view of the same. 11 , 21 , 31 . 41...dielectric, 1
2, 22, 32. 42...Inner conductor, 1
3, 23, 33. 43...Outer conductor, 1
4, 24, 34. 44... Short circuit conductor, 15, 2
5, 35. 36...river/step, 16, 26, 37.4
6...Open surface. Name of agent: Patent attorney Shigetaka Awano and 1 other person

Claims (1)

[Claims] A dielectric body is hollow and has a prismatic outer shape, and at least one step is provided on the inner periphery of this dielectric, and one side has a square cross-sectional inner periphery shape and the other has a step portion as a boundary. The hollow portion is formed to have a circular inner circumferential cross-sectional shape, and an inner conductor and an outer conductor are provided covering the inner circumferential surface and outer circumferential surface of the dielectric, respectively, and a short circuit is provided in which the inner conductor and the outer conductor are electrically connected. A coaxial dielectric resonator, characterized in that a conductor is provided on one end surface of the dielectric.