JPS62108601A - Coaxial resonator filter - Google Patents

Abstract

PURPOSE:To improve the mass-productivity by making the length of each resonator equal to each other and applying chamfering to the edge of the inner face of each resonator thereby facilitating the adjustment of the resonance frequency in using plural cylindrical coaxial resonators with different resonance frequency to obtain a desired characteristic. CONSTITUTION:The coaxial resonator filter consists of coaxial resonators 28-30, a case 22 and tuning screws 25-27. Chamfering parts 31, 32 are formed respectively to the lower end of the coaxial resonators 28 and 30. Although the resonance frequency differs from the coaxial resonators 28-30, the length is made equal. Thus, the adhesion between the bottom face of the coaxial resonators 28-30 and the case 22 is excellent, good earthing is applied and the high frequency characteristic is improved, the adhesive strength with the case 22 is high thereby obtaining the filter with high vibration resistance and high reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a filter using a coaxial resonator.

BACKGROUND ART Conventionally, when constructing a coaxial filter using a coaxial dielectric resonator, a plurality of 3-element, 6-element, etc. resonators are arranged in the coaxial dielectric resonator in order to obtain the desired filter characteristics. configured a filter.

These multiple resonators are arranged by grinding the length of each element using a grinder or the like to match the resonant frequency of the two inputs, and then attaching them to the case by soldering or using conductive adhesive. It was fixed with

FIG. 4 shows a conventional example.

In Fig. 4, reference numeral 1 denotes a case, which is provided with tuning screws 2, 3, and 4 for fine frequency adjustment, and is used to adjust the frequency after assembly. 6, 6 are input/output connectors, 7, 8
．． '9 is a dielectric material, chlorine titanate porcelain or M
gTi○3t Ca T 103 type porcelain is used. Silver electrodes 10, 11 and 12 are applied and baked on the outer periphery, inner periphery and end faces of the dielectrics 7 and 8.9, respectively. Reference numerals 13, 14 and 15 are rod-shaped metal conductors, respectively, which are fixed to the inner circumferential portion of the dielectric 7° and 8.9 with solder. Reference numeral 16 denotes a substrate, which is made of alumina, Teflon, or the like, and is formed so as to obtain a coupling capacitance by a counter electrode 17 provided on the upper surface of the substrate 16.

Problems to be Solved by the Invention However, the conventional filters described above have coaxial resonators with different lengths in order to equalize the resonant frequencies of the three coaxial resonators that are combined. As a result, the case 1 and the electrodes 1o and 12 were not uniformly grounded, resulting in poor insertion loss, spurious, and other characteristics.

Also, in order to obtain the interstage capacitance used for coupling the resonators, 16
When a counter electrode 17 is used, the distance between the resonator and the substrate 16 may become uneven, which poses a problem in terms of mass production.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate such drawbacks of the conventional filter, to easily adjust the resonance frequency, and to construct a filter that can be easily mass-produced.

Means for Solving the Problems ゛The present invention has been made to achieve the above object.□ Therefore, in a TEM coaxial resonator, in order to obtain a desired resonance frequency, the length of the resonator and the end face on the inner conductor side are adjusted. The radius of the chamfered portion of the corner that touches the surface is set appropriately.

EXAMPLE An example of the coaxial resonator filter of the present invention will be described below.

, FIG. 1 is a sectional view of a coaxial resonator of the present invention, and FIG. 2 is a coaxial resonator used in the same embodiment. 1 in Figure 2
Reference numeral 8 denotes a dielectric material of a cylindrical coaxial resonator, which is made of titanium oxide based material. 19 coats and prints silver paste on the dielectric 18 with an electrode, and then 8o.

An electrode film is formed by baking at a high temperature of °C. 2o is a part of the corner where the inner conductor 2, the J electrode, and the end surface of 9 come into contact, and is chamfered. Here, when the radius of the chamfered portion is increased, the apparent dielectric constant of the dielectric 18 decreases, and the resonant frequency also changes in proportion to this.

Figure 3 shows that when the resonant frequency of the coaxial resonator is kept constant,
, which shows the relationship between the chamfer dimensions and the length of the resonator. Here, the diameter is 10m/m, and the inner diameter is 3.0tran.
A coaxial resonator was used as a sample. When constructing a filter, filters with different resonance frequencies are combined. Here, when a filter with three stages of elements of 999111h and 1039m is configured, the size is 5 bases as shown in Fig. 3.

By combining resonators with different chamfer dimensions, the lengths of the resonators can be made equal.

Figure 1 shows an embodiment of the coaxial resonator filter of the present invention. 022 is a filter case, 23, 24 are connectors for input and output, and 025, 2, 6, and 27 are connectors for the resonance frequency. It is a tuning screw for adjustment,
Adjustments are made during the final inspection of the filter. 2
B, 29.30 are coaxial resonators, respectively, and chamfered portions 31, 3.2 are formed at the lower ends of the coaxial resonators 28 and 3o. and coaxial resonator 28. ．． 29.30 have significantly different resonant frequencies, but as can be seen from the figure, the lengths of the resonators are the same. Therefore, coaxial resonance, vessel 28, 29° 30
Good adhesion between the bottom surface of the case 22 and the case 22, good grounding, and good high frequency characteristics.

In addition, since the adhesion strength with the case 22 is high, it is possible to provide a filter with high vibration resistance and high reliability.

Effects of the invention 1. - As described above, the present invention provides a plurality of cylindrical coaxial resonators 6 vanes, chamfers are provided on the inner edges of the coaxial resonators, and each coaxial resonator has the same length. Therefore, it is easy to ground each coaxial resonator, improving characteristics and making assembly easier.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing one embodiment of the coaxial resonator filter of the present invention, Fig. 2 is a cross-sectional view of the same main part, Fig. 3 is a characteristic diagram of the coaxial resonator, and Fig. 4 is a conventional coaxial resonator filter. FIG. 3 is a cross-sectional view of a resonator filter. 22... Case, 25, 26, 27...
・Tuning screw, 28, 29, 3o... Coaxial resonator, 31.32... Chamfered part. Name of agent: Patent attorney Toshio Nakao and 1 other person22
- Case 23 - One person's power is 1,700 yen Figure 1
24■1 sword ゛'25~27--Teyumi) Bu, 2:
) 28~Goo axisable phantom eye 4 jl, 32-Ichikko■7 So part 2nd figure 18-E body rq--tgx 20--Kor-R-tongue, 21-p[I5 3rd Figure L--Case t-1 Kaliful 9--Name' shih 2nd book ((0~P2-1ginc, q 13JJ---4-for, 4he16---Group 1 anti

Claims (1)

[Claims] At least one of the plurality of cylindrical tuned resonators having different tuning frequencies is provided, at least one of the plurality of coaxial resonators has a chamfered inner surface end, and at least one of the plurality of coaxial resonators has a chamfered inner surface end. One is a coaxial resonator filter that is different from other coaxial resonators in its presence or absence of chamfering or its shape and dimensions.