JPH0317444Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a coupling structure applied to distributed constant filters and the like.

(Conventional technology) Conventionally, as a filter in the several 100 MHz range, LC
There are some that use resonant circuits and others that use coaxial cavity resonators, but they are structurally unstable or complex, have unsatisfactory characteristics, take time to adjust, and cannot reduce costs. There were other problems.

For this purpose, as shown in FIG. 3, two through holes 12 and 13 are provided in the dielectric block 11, and conductive films 14 and 15 are provided on the inner surfaces of these through holes 12 and 13. A conductive film 16 is provided on the side surface, and the conductive films 14 and 15 are provided on the inner surfaces of the through holes 12 and 13, and the dielectric block 1
The conductive film 16 provided on the conductive film 1 and the dielectric block 11 interposed therebetween constitute a pair of resonant units, and the dielectric block 1 between these resonant units
1 is provided with a cavity 17, and furthermore, an external circuit (not shown) and the above-mentioned resonance unit are electrostatically coupled by an input coupling capacitor 18 and an output coupling capacitor 19, respectively, as shown in FIG. 4. There is a distributed constant type filter with .

In Fig. 4 above, 21 is an input terminal, 22 is an output terminal, 23 is an input coupling capacitance, 24 is an output coupling capacitance, and 25 and 26 are 1/4 wavelength resonant circuits shown as lumped constant circuits. It is. Therefore,
The distributed constant type filter shown in FIG. 3 is a filter in which the 1/4 wavelength resonant circuits are inductively coupled to each other, and the external circuit and the 1/4 wavelength resonant circuit are capacitively coupled.

By the way, in the distributed constant type filter shown in FIG. 3, an input coupling capacitor is used, in which a mounting member 31 made of a metal cylinder or a conductive paste is connected and fixed to a conductive film 14, and counter electrodes 33 and 34 are formed on a columnar dielectric body 32. 18 of the counter electrodes 33 are connected and fixed to the mounting member 31, and the mounting member 35 is also connected and fixed to the conductive film 15 in the same manner as above, and counter electrodes 37 and 38 are formed on the columnar dielectric 36. Since the opposing electrode 37 of the capacitor 19 is connected and fixed to the mounting member 35, the work of mounting the input coupling capacitor 18 and the output coupling capacitor 19 is troublesome.

A distributed constant filter capable of solving such problems is described in, for example, Japanese Patent Laid-Open No. 194405/1983. This is the input above,
Input instead of output coupling capacitors 18 and 19,
An output coupling dielectric unit (coupling terminal) is inserted into the through holes 12 and 13. This coupling dielectric unit is formed into a columnar shape by coating a portion of a conductive wire with a diameter of, for example, 0.5 mm with a dielectric material such as plastic or titanium oxide. At the tip of the dielectric unit,
A tapered portion is formed to facilitate press-fitting into the through holes 12 and 13, and a flange portion is formed at the rear end portion to regulate the amount of insertion.

(Problem to be solved by the invention) However, in the coupling structure described in the above publication, a conductor wire coated with a plastic or titanium oxide dielectric is used as the coupling dielectric unit (coupling terminal). Therefore, for example, when plastic is applied, it is difficult to secure the necessary dielectric constant. On the other hand, when titanium oxide ceramic is applied, press-fitting is difficult, and gaps tend to form between the outer surface of the coupling unit and the inner conductor, making the capacitive coupling capacitance unstable. There is a problem in that variations tend to occur between products.

The present invention was made to solve the above-mentioned conventional problems, and is a dielectric resonator that can easily and reliably perform press-fitting work, stabilizes capacitance, and prevents variations between products. The purpose is to provide an input/output coupling structure.

(Means for solving the problem) The present invention forms a through hole in a dielectric block,
Forming an inner conductive film on the inner surface of the through hole,
A dielectric resonator is formed by forming an outer conductive film on the four sides and the short-circuit side end face of the dielectric block, and a dielectric is coated on a part of the conductor wire in a space surrounded by the inner conductive film. Press-fit the coupling dielectric unit made of
In the input/output coupling structure in which the conductor wire and the inner conductive film are electrostatically coupled, the dielectric of the coupling dielectric unit is composed of a dielectric ceramic and an insulating polymer material with a predetermined dielectric constant. It is characterized by being a composite dielectric material made by mixing and elasticity.

(Function) According to the input/output coupling structure of the dielectric resonator according to the present invention, the coupling dielectric unit is made of a composite dielectric made of a mixture of dielectric ceramic and an insulating polymer material, such as an insulating resin. With this structure, the necessary dielectric constant can be ensured by the dielectric ceramic, and elasticity can be ensured by the insulating resin. As a result, the elasticity makes the press-fitting operation easy and reliable, and there is no gap between the coupling dielectric unit and the inner conductive film.

Here, in the conventional example described in the above publication, a tapered part is provided to facilitate press-fitting, and the elasticity of the material is used to facilitate press-fitting and prevent gaps with the inner conductive film. The idea of doing so is not stated. In contrast, the present invention achieves both the necessary dielectric constant and elasticity by mixing dielectric ceramic and insulating polymer material.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In FIG. 1, 11 is a rectangular parallelepiped dielectric block made of titanium oxide ceramic dielectric;
2 and 13 are through holes, 14 and 15 are conductive films provided on the inner surfaces of these through holes 12 and 13, respectively, 16 is a conductive film provided on at least four sides of the dielectric block 11, and 17 is a cavity, The above is the same as the distributed constant type filter shown in FIG.

In the distributed constant type filter shown in FIG. 1, dielectric units (coupling terminals) 41, as shown in FIG. 41 are press-fitted respectively.

As shown in FIG. 2, the dielectric unit 41 includes a part of a conductive wire 42 having a diameter of, for example, 0.5 mmφ.
A composite dielectric material made by mixing a dielectric ceramic and an insulating polymer material so as to obtain a predetermined dielectric constant and elasticity is deposited and formed into a columnar shape, and the conductive wire 42 passes through the axial center. The tip of the dielectric unit 41 is provided with a tapered portion 43 in order to facilitate press-fitting into the holes 12 and 13 of the dielectric block 11. At the rear end, there is a dielectric block 1.
A flange portion 44 is provided which is abutted against the opening periphery of the holes 12 and 13 on the side where the conductive film 16 is not formed.

As shown in FIG. 1, the dielectric units 41, 41 are formed from a dielectric block 1 having conductive films 14, 15 formed on the inner surface thereof, from the tapered portions 43, 43 side.
Dielectric units 41 and 4 are inserted into the holes 12 and 13 of 1.
The flange portions 44, 44 of 1 are the dielectric block 11
It is press-fitted until it makes contact with the

By doing as described above, the conductive wires 42, 42 and the conductive films 14, 15 formed on the inner surfaces of the holes 12, 13 of the dielectric block 11 can be connected to the dielectric unit 41,
The input coupling capacitor 18 as shown in FIG.
The output coupling capacitor 19 becomes unnecessary.

Therefore, there is no need for troublesome installation work such as the input coupling capacitor 18 and the output coupling capacitor 19.

A conductive film for generating coupling capacitance may be formed on the side peripheral surfaces of the dielectric units 41, 41. In this case, capacitance is generated between the conductive wires 42, 42 and the conductive film, and the conductive films and the conductive films 14, 15 are electrically connected.

Suitable materials for the dielectric unit 41 include those disclosed in Japanese Patent Application Laid-open Nos. 166605 to 166609, for example. Such materials have appropriate elasticity and dielectric constant required by the present invention. In other words, if you want to widen the passband characteristics of a filter, the dielectric constant of the dielectric unit 41 must be large, but if you use plastic alone, it is difficult to obtain the required dielectric constant.On the other hand, plastic is easy to obtain appropriate elasticity and can be molded. It's also easy and cheap. As mentioned above, the dielectric units 41, 41 must be press-fitted into the holes 12, 13 of the dielectric block 11, and the dielectric units 41, 41 must be press-fitted into the holes 12, 13 of the dielectric block 11.
If there is a gap between the surfaces of conductive films 14 and 15, the capacitance of capacitance becomes unstable, and variations between products increase, making it impossible to obtain products with stable quality. Therefore, appropriate elasticity is essential. If the dielectric units 41, 41 are manufactured only from dielectric ceramic in order to obtain the necessary dielectric constant, such appropriate elasticity will not be obtained, and molding will be troublesome, leading to an increase in cost. Therefore, in the present invention, the dielectric unit 4 is made of the above-mentioned composite dielectric material made by mixing a dielectric ceramic and an insulating polymer material so as to obtain appropriate dielectric constant and elasticity.
1,41 was produced.

The shape of the dielectric units 41, 41 is not limited to the above-mentioned example. For example, the inner diameter of the through holes 12, 13 may change midway in the axial direction. When used in a resonator with a large inner diameter on the end side, one having an outer diameter corresponding to the change in the inner diameter is used.

The present invention is not limited to the distributed constant filter shown in FIG. 1, but can be widely applied to other high frequency components.

For example, in addition to the dielectric coaxial resonator having the above-mentioned structure, a single dielectric coaxial resonator in which an inner conductor film and an outer conductor film are formed on the inner and outer peripheral surfaces of a cylindrical or prismatic dielectric material are used. The present invention can also be applied to resonators.

(Effects) As is clear from the above detailed description, according to the input/output coupling structure of the dielectric resonator according to the present invention, the dielectric ceramic and the insulating material are connected in the space surrounded by the inner conductive film. Since the coupling dielectric unit using a composite dielectric mixed with a polymeric material is press-fitted, it is easier to achieve the necessary dielectric constant and appropriate elasticity than when manufacturing with only either ceramic or plastic. It is possible to obtain stable characteristics at low cost.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a distributed constant type filter, which is an example of the application of the present invention, Fig. 2 is a front view of a dielectric unit, Fig. 3 is a longitudinal cross-sectional view of a conventional distributed constant type filter, and Fig. 4. is an equivalent circuit diagram of the distributed constant filter shown in FIG. 1 is a dielectric block, 12 and 13 are through holes, 1
4 and 15 are inner conductive films, 16 is an outer conductive film, 41 is a coupling dielectric unit, 42 is a conductor wire, and 44 is a composite dielectric.

Claims (1)

[Scope of utility model registration request] A dielectric resonator in which a through hole is formed in a dielectric block, an inner conductive film is formed on the inner surface of the through hole, and an outer conductive film is formed on the four sides and the short-circuit side end face of the dielectric block, A coupling dielectric unit, which is formed by coating a part of the conductor wire with a dielectric material, is press-fitted into the space surrounded by the inner conductive film to electrostatically couple the conductor wire and the inner conductive film. In the input/output coupling structure, the dielectric of the coupling dielectric unit is a composite dielectric made by mixing a dielectric ceramic and an insulating polymer material so as to obtain a predetermined dielectric constant and elasticity. An input/output coupling structure of a dielectric resonator characterized by the following.