JPH07202527A - Dielectric coaxial resonator and conductive film forming method for same - Google Patents

Abstract

PURPOSE:To easily produce the dielectric coaxial resonator and to simplify a utilization by standardizing the external shape. CONSTITUTION:An electrode 4 is formed on an inside peripheral face 2A of a through hole 3, outside peripheral faces 2B parallel with the axis, and one end face 2C of a prismatic dielectric 2, which has a square section and has the circular through hole 3 formed on the axis and is made of ceramics or the like, to constitute a dielectric coaxial resonator 1. Dimensions L1 in the axial direction of the dielectric 2 are made longer than dimensions L2 in the axial direction based on the wavelength of the resonance frequency of the electrode 4, and the dimensions L2 in the axial direction of the electrode 4 are adjusted to easily constitute the dielectric coaxial resonator having an arbitrary resonance frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric coaxial resonator in which a conductive coating is formed on the inner and outer peripheral surfaces of a columnar dielectric having a hole extending in the axial direction, and a dielectric coaxial resonator. The present invention relates to a conductive film forming method.

[0002]

2. Description of the Related Art FIG. 15 is a perspective view showing a conventional dielectric coaxial resonator, and FIG. 16 is a view showing a manufacturing process of the conventional dielectric coaxial resonator.

The dielectric coaxial resonator 100 shown in the figure is a quarter-wave dielectric coaxial resonator with a short-circuited termination, and has a wavelength of approximately λg /.
4 (λg: tube wavelength λg of resonance frequency fo) in the axial direction, and a dielectric 101 made of prismatic ceramics or the like having a square cross section with a circular through hole 102 formed on the central axis. Of the inner peripheral surface 101A of the through hole 102, the outer peripheral surface 101B parallel to the axis, and the one end surface 101C with copper,
It is configured by forming a metal film K of silver or the like.

The metal film K covering the inner peripheral surface 101A constitutes the inner conductor of the coaxial resonator, and the outer peripheral surface 101 is formed.
The metal film K covering B constitutes the outer conductor of the coaxial resonator, and the inner conductor and the outer conductor are short-circuited by the metal film K formed at the one end 101C, and a quarter of the terminal short circuit is formed.
A wavelength coaxial resonator is configured.

The dielectric coaxial resonator 100 has a λg / 4
A coating material tank 1 in which a prismatic dielectric 101 having the above axial dimension L'is filled with a conductive coating material 103 such as copper or silver.
04 (FIG. 16 (a)), and the through hole 1
No. 02 inner peripheral surface 101A, outer peripheral surface 101B and both end surfaces 10
After the conductive coating material 103 is applied to 1C and 101D,
A metal film K is formed on the entire dielectric 101 by heating at a predetermined firing temperature.
Is formed (FIG. 16B), and then one end of the dielectric 101 is polished until the axial dimension L becomes approximately λg / 4 (FIG. 16C).

[0006]

In the conventional dielectric coaxial resonator, since the axial dimension L is set to approximately λg / 4, the axial dimension L differs depending on the resonance frequency fo. Therefore, as shown in FIG. 17, a plurality of dielectric coaxial resonators 100 having different resonance frequencies fo are connected to the open end face 101.
When a dielectric filter is formed by arranging D in parallel and cascade-connecting via the coupling substrate 105 arranged in front of the open end surface 101D, the surface of the termination surface 101C of the dielectric coaxial resonator 100 is It becomes uneven, and it is difficult to effectively use the accommodation space of the dielectric filter.

Further, in the conventional method for manufacturing a dielectric coaxial resonator, after covering the entire dielectric 101 with a conductive member, one end face is polished to form an open end face and the axial dimension L is set to a predetermined value. Since the dimensions are adjusted, it takes a long time for the polishing process and a long time for manufacturing. In particular, when the number of types of the resonance frequency fo of the dielectric coaxial resonator is increased, the work content of the polishing process is increased, the manufacturing process becomes complicated, and standardization becomes difficult.

The present invention has been made in view of the above problems, and a dielectric coaxial resonator having a standardized external shape and easily applied to a dielectric filter or the like, and a dielectric coaxial resonator easily manufactured. It is intended to provide a manufacturing method.

[0009]

According to the present invention, at least one of an outer peripheral surface parallel to the axis of a columnar dielectric body having one or more axially extending holes, an inner peripheral surface of the hole, and a hole is provided. In the dielectric coaxial resonator in which the end face of is covered with a conductive material, the dielectric has an axial dimension longer than a predetermined dimension based on the wavelength of the resonance frequency, and the inner and outer peripheral surfaces of the dielectric are Is covered with the conductive material by the predetermined size from the end face (claim 1).

Further, the present invention is a method of manufacturing the above dielectric coaxial resonator, wherein the upper end of the hole is closed above the conductive material tank containing the liquid conductive material so that the dielectric is vertically aligned. A first step of arranging and immersing the dielectric in the tank in a first atmospheric pressure by a predetermined dimension based on a wavelength of a resonance frequency to apply a conductive material to a lower end surface and an outer peripheral surface of the dielectric; In a state where the dielectric is immersed in the conductive material bath, the atmospheric pressure is increased to a predetermined second atmospheric pressure higher than the first atmospheric pressure to apply the conductive material on the inner peripheral surface of the dielectric by the predetermined size. 2 steps,
The third step comprises firing a dielectric material coated with a conductive material at a predetermined high temperature to form a conductive coating (claim 2).

[0011]

According to the first aspect of the invention, the axial dimension of the dielectric is made longer than the axial dimension of the conductive material coated on the inner and outer peripheral surfaces, and the axial dimension of the conductive material is the resonance frequency. Since the predetermined size is set based on the wavelength of, the outer shape of the dielectric can be standardized to the same shape regardless of the resonance frequency.

According to the second aspect of the present invention, the dielectric coating material having the through hole sealed at the upper end is formed into a liquid conductive coating material in a first atmospheric pressure by a predetermined dimension based on the wavelength of the resonance frequency. When immersed in a coating material tank filled with, the conductive coating material is applied to the lower end surface of the dielectric and the outer peripheral surface parallel to the axis from the lower end to a specified size, and only the lower end is conductive on the inner peripheral surface of the through hole. A coating material is applied.

In this state, when the atmospheric pressure is increased from the first atmospheric pressure to the second atmospheric pressure, the liquid surface of the coating material tank is pushed down in accordance with the increase of the atmospheric pressure, and the liquid surface of the conductive material in the through hole rises. The conductive coating material is applied to the inner peripheral surface of the through hole from the lower end by a predetermined size. Thereafter, by heating the dielectric material coated with the conductive coating material at a predetermined firing temperature, the conductive coating material is sintered on the surface of the dielectric material to form a conductive coating film.

[0014]

1 is a perspective view showing a first embodiment of a dielectric coaxial resonator manufactured by an electrode forming method according to the present invention,
FIG. 2 is a vertical sectional view of the same dielectric coaxial resonator.

The dielectric coaxial resonator 1 has a square cross-sectional shape, and the inside of the through hole 3 of the columnar dielectric 2 made of ceramics or the like in which the circular through hole 3 is formed on the central axis. The peripheral surface 2A, the outer peripheral surface 2B parallel to the axis, and the one end surface 2C are
It is formed by coating with an electrode (conductive material) 4 such as copper, silver, or platinum. The cross-sectional shape can be any cross-sectional shape such as a circle or an ellipse.

The electrode 4 covering the inner peripheral surface 2A of the dielectric 2 constitutes the inner conductor of the coaxial resonator, and the outer peripheral surface 2
The electrode 4 formed by coating B constitutes an outer conductor of the coaxial resonator, and the electrode 4 coated on the one end face 2C short-circuits the inner conductor and the conductor to form a short-circuited coaxial resonator. ing.

The dielectric 2 has an axial dimension L1 longer than λg / 4, and the inner peripheral surface 2A and the outer peripheral surface 2B have a predetermined dimension L2 at which one end 2C resonates at a desired resonance frequency fo. The electrode 4 is covered. In addition, this dimension L
2 is different from the design value due to the influence of the electric field distribution at the open end and is calculated in advance by experiments or the like, and is a dimension shorter than λg / 4.

Then, by setting the axial dimensions of the inner conductor and the outer conductor as described above, the dielectric coaxial resonator 1
Is a quarter-wave coaxial resonator with a short-circuited termination.

FIG. 3 is a schematic view showing a method for forming electrodes of a dielectric resonator according to the present invention. FIG. 3A is a state before the dielectric is immersed in a coating material tank containing a liquid conductive coating material. , (B) is a diagram showing a state where the dielectric is immersed in the coating material tank, (c) is a diagram showing a state where the atmospheric pressure is increased while the dielectric is immersed in the coating material tank, (d) Is a diagram showing a state in which the atmospheric pressure is lowered while the dielectric is pulled up from the coating material tank,
(E) is a figure which shows the baking process of the electroconductive coating material apply | coated to the dielectric material.

In the figure, the closed container 5 has a pump 6 connected to the outside so that the atmospheric pressure in the container can be changed. A paste tank (conductive coating material tank) 8 containing a liquid conductive coating material (hereinafter referred to as an electrode paste) 7 such as copper, silver or platinum is arranged inside the closed container 5.

Further, the furnace 9 is a tunnel-shaped electric furnace in which a plurality of temperature tanks are connected to each other, and a belt conveyer 91 for conveying an object to be heated is provided in a passage in the furnace. Each temperature layer is kept at a predetermined temperature based on a preset firing process, and the dielectric material 2 coated with the electrode paste is conveyed from the upstream side to the downstream side at a predetermined speed by the belt conveyor 91, and The dielectric 2 is heated at a predetermined firing temperature.

The manufacturing process of the dielectric coaxial resonator 1 includes a coating process of applying the electrode paste 7 to the columnar dielectric 2 and a baking process of baking the electrode paste 7 applied to the dielectric to form a metal film. It consists of and. Fig.3 (a)-
(D) corresponds to the coating step, and (e) in the figure corresponds to the firing step.

The dielectric coaxial resonator 1 is manufactured by the following procedure. First, the low pressure P is generated in the closed container 5 by the pump 6.
Hold on. Next, the dielectric 2 having the upper end of the through hole 3 hermetically sealed is vertically arranged above the paste tank 8 in the hermetic container 5 (FIG. 3A). Then, in the state of the low pressure P, the dielectric 2 is vertically lowered, and the paste tank 8 is moved from the lower end thereof by a predetermined dimension L2 based on the wavelength of the resonance frequency fo.
(Fig. 2 (b)). Thereafter, the pump 6 is used to set the pressure inside the closed container 5 to a predetermined pressure P ′ higher than the pressure P.
The pressure is increased to ((c) in the figure).

As shown in FIGS. 4 (a) and 4 (b), the atmospheric pressure P'in the electrode paste 7 is such that the liquid surface M1 of the electrode paste 7 in the through hole 3 is in contact with the outer peripheral surface 2B of the dielectric 2. Liquid level M
The pressure rises to 2. That is, the volume in the through hole 3 is V (see FIG. 4A), and the volume in the through hole 3 when the liquid level M1 of the electrode paste 7 rises to the liquid level M2 is V ′ (FIG. 4 ( b)), P.
・ V = P '・ V' holds, so the atmospheric pressure P'is P '=
It is calculated by (P · V) / V ′.

Then, the dielectric 2 is pulled up from the paste tank 6 and the pressure is lowered to a predetermined atmospheric pressure P ″ lower than the atmospheric pressure P to discharge the paste accumulated in the through holes 3 (FIG. 3 (d)). After drying the electrode paste 7 applied to the dielectric 2, the electric paste 9 is heated at a predetermined firing temperature to sinter the electrode paste 7 and form an electrode coating on the peripheral surface of the dielectric 2. (FIG.3 (e)).

As described above, the axial dimension L1 of the dielectric 2 of the dielectric coaxial resonator 1 is made longer than the axial dimension L2 of the electrodes 4 forming the inner conductor and the outer conductor, and the dielectric 2 is formed. Since the axial dimension L2 of the electrode 4 is adjusted, the manufacture of the dielectric coaxial resonator 1 is simplified.

Since the outer dimensions of the dielectric coaxial resonator 1 can be made constant regardless of the resonance frequency fo,
Designing a device to which the dielectric coaxial resonator 1 is applied is facilitated. For example, in a dielectric filter formed by connecting a plurality of dielectric coaxial resonators in cascade, as shown in FIG. 5, the open end surface 2D and the end surface 2 of the all-dielectric coaxial resonators 1 arranged in parallel are arranged.
Since C is flush, a dead space does not occur at the position where the dielectric coaxial resonator 1 is arranged, and the structure of the dielectric filter can be made compact and robust.

Although the above embodiment has been described with respect to the dielectric coaxial resonator alone, in the present invention, electrodes are formed on the inner peripheral surface and the outer peripheral surface of the dielectric having a plurality of through holes in the axial direction. It can also be applied to the structure of the integrally formed dielectric filter configured.

As a method of manufacturing the dielectric coaxial resonator 1, an electrode is formed on the inner peripheral surface of the through hole by immersing the dielectric material in a paste tank by a predetermined size and changing the atmospheric pressure before and after the immersion. Since the axial dimension L2 of the electrode is controlled, the electrode can be formed with relatively high accuracy by a simple method, and fine adjustment of the dimension of the electrode due to cutting can be reduced.

In the above-mentioned embodiment, since the dielectric material having the through hole is used, the open end face side of the through hole is sealed with a plug or the like when immersed in the paste tank. Instead of this, a dielectric having a non-through hole may be used. With this dielectric, it is not necessary to seal the open end face side of the through hole as described above, so there is an advantage that the electrode forming work becomes easier.

FIG. 6 is a perspective view showing an example of the structure of a dielectric coaxial resonator using a dielectric having a non-through hole, and FIG.
It is a longitudinal cross-sectional view of the same dielectric coaxial resonator.

The dielectric 11 of the dielectric coaxial resonator 10 has a square cross-sectional shape, and a circular non-through hole 12 parallel to the axis is formed at the center of one end face 11A. Dielectric 11
The inner peripheral surface of the hole 12 of the inner conductor electrode 1 is only on the surface parallel to the axis.
3 is formed. Further, strip-shaped input / output terminal electrodes 15 and 16 are formed on the outer peripheral surface of the dielectric 11 at positions facing the tip of the hole 12, and the terminal electrodes 15 and 1 are formed.
An outer conductor electrode 14 is formed in a portion that surrounds 6 and faces the non-through hole 12. The inner conductor electrode 13 and the outer conductor electrode 14 are terminated by a short circuit electrode 17 formed on the entire end surface 11A.

In this dielectric coaxial resonator 10, signals are input and output via coupling capacitors C1 and C2 formed between the terminal electrodes 15 and 16 and the inner conductor electrode 13, and the equivalent circuit is shown in FIG. As shown in. Structurally, a dielectric layer is formed on the open end surface of the dielectric coaxial resonator 1 shown in FIG. 1, and the outer peripheral surface 2 of the dielectric coaxial resonator 1 shown in FIG.
If electrodes corresponding to the above-mentioned terminal electrodes 15 and 16 are formed at appropriate positions in B, the dielectric coaxial resonator 10 is substantially the same.

In the dielectric coaxial resonator 10, after the electrodes 4 are formed on the one end surface 11A, the outer peripheral surface and the inner peripheral surface of the dielectric 11 by the method described above, the terminal electrodes 15, 1 on the outer peripheral surface 11B are formed.
The terminal electrode 1 is formed by removing the electrode 4 around the formation position of 6
It is manufactured by the procedure of forming 5, 16.

Instead of the terminal electrodes 15 and 16, only one input / output terminal electrode may be formed on the open end surface 11D.

When a dielectric having two or more non-through holes is used, an integrally molded dielectric filter can be easily constructed.

FIG. 9 is a perspective view showing a first embodiment of an integrally molded dielectric filter manufactured by the electrode forming method according to the present invention, and FIG. 10 is a longitudinal sectional view of the same molded dielectric filter. FIG. 11 is an equivalent circuit diagram of the same-body molding type dielectric filter.

The dielectric filter 20 has a rectangular cross section, and is constructed by using a dielectric 21 made of prismatic ceramics or the like having a pair of non-through holes 22 and 23 parallel to the axis. It is a surface-mountable integrally-formed dielectric filter.

As shown in the equivalent circuit of FIG. 11, the dielectric filter 20 is formed by integrally molding two dielectric coaxial resonators θ1 and θ2, and has one wide side surface parallel to the axis of the dielectric 21. 21A is the mounting surface. Inner peripheral surfaces 21E and 21F of the non-through holes 22 and 23 of the dielectric 21 are end surfaces 21G.
The electrode 4 is formed by a predetermined dimension L2 from the side surface 21
A pair of strip-shaped terminal electrodes 2 are provided at positions facing the electrodes 4 formed at the tip closed portions of the non-through holes 22 and 23 of A.
4, 25 are formed.

The terminal electrode 24 is formed around the side surface 21B in contact with the side surface 21A, and the terminal electrode 25 is formed around the side surface 2C in contact with the side surface 21A. Further, the electrode 4 is formed on the entire side surfaces 21A to 21D of the dielectric 21 and both end surfaces 21G and 21H so as to surround the terminal electrodes 24 and 25.

The electrodes 4 formed on the side surfaces 21A to 21D constitute a common outer conductor of the dielectric coaxial resonators θ1 and θ2, and the electrodes 4 formed on the inner peripheral surfaces 21E and 21F respectively. The electrode 4 that forms the inner conductor of the dielectric coaxial resonators θ1 and θ2 and that is formed on the end face 21G forms the short-circuit electrode between the inner conductor and the outer conductor.

The dielectric coaxial resonators θ1 and θ2 are magnetically coupled by the magnetic field formed in the dielectric 21, and the external coupling capacitance C is provided between the terminal electrode 24 and the electrode 4 on the inner peripheral surface 21E.
e1 is configured, and the terminal electrode 25 and the electrode 4 on the inner peripheral surface 21F
An external coupling capacitance Ce2 is formed between them.

Further, the grounding capacitances Cs1 and Cs are provided between the electrode 4 and the end surface 21H which are formed at the tip closed portions of the non-through holes 22 and 23.
2 are configured. The ground capacitances Cs1 and Cs2
Contributes to the axial dimension L1 of the dielectric filter 20, and the axial dimension L1 can be shortened by appropriately setting.

In the dielectric filter 20, the end face 21H side of the dielectric 21 is immersed in the paste tank 8 to apply the electrode paste 7 to the end face 21H and a part of the side faces 21A to 21D, and the above Boyle's law is applied. After applying the electrode paste 7 to the end face 21G, the remaining portions of the side faces 21A to 21D, and the inner peripheral faces 21E and 21F of the dielectric 21 by the method used, the dielectric paste 21 is baked at a predetermined temperature in the electric furnace 9. The electrode 4 is formed, and then the side surfaces 21A, 21B, 21C are formed.
The electrode 4 around the formation position of the terminal electrode is peeled off to form the terminal electrodes 24 and 25, which is manufactured.

FIG. 12 is a perspective view showing a second embodiment of an integrally molded dielectric filter manufactured by the electrode forming method according to the present invention, and FIG. 13 is a vertical sectional view of the same molded dielectric filter. is there.

The integrally molded dielectric filter 2 shown in FIG.
In FIG. 9, 0'denotes the non-through holes 22, 2 of the end face 21H.
The non-through holes 26 and 27 are formed at the same position as the position 3 in FIG. Therefore, the holes 22 and 26 and the holes 23 and 27 are separated by the partition walls 28 and 29, respectively. Inner peripheral surfaces 21I, 21J parallel to the axes of the holes 26, 27
The electrode 4 is formed from the end face 21H by a predetermined dimension L3.

The ground capacitance Cs1 is provided between the electrode 4 formed on the inner peripheral surface 21I and the electrode 4 formed on the inner peripheral surface 21E.
The ground capacitance Cs2 is formed between the electrode 4 formed on the inner peripheral surface 21J and the electrode 4 formed on the inner peripheral surface 21F. Therefore, the ground capacitances Cs1 and Cs2 can be adjusted to the required capacitance values by adjusting the length dimension L3 of the electrode 4 formed on the inner peripheral surfaces 21I and 21J.

The integrally-molded dielectric filter 20 'is also manufactured by the same procedure as that of the integrally-molded dielectric filter 20. However, when the electrode paste 7 is applied to the end surface 21H side of the dielectric 21, the above-mentioned boiling Dimension L3 of the electrode paste 7 applied to the inner peripheral surfaces 21I and 21J by the method using the law
It is possible to adjust the ground capacitances Cs1 and Cs2 with relatively high accuracy by adjusting.

In the second embodiment, the integrally molded dielectric filter having no coupling hole has been described, but the electrode forming method according to the present invention is also applied to the integrally molded dielectric filter having the coupling hole. be able to.

That is, as shown in FIG. 14, when the viscosity of the electrode paste 7 is increased, the dielectric 30 is moved to the paste bath 8
When soaked in, the electrode paste 7 penetrates into the holes 31 and 32 having a large diameter, but the electrode paste 7 does not penetrate into the bonding hole 33 having a small diameter due to surface tension.
By appropriately adjusting the viscosity of the electrode paste 7 in accordance with the diameter of the electrode, the electrode can be formed only on the inner peripheral surfaces of the holes 31 and 32.

[0051]

As described above, according to the present invention,
In a dielectric coaxial resonator in which an outer peripheral surface parallel to the axis of a columnar dielectric body having a through hole extending in the axial direction, an inner peripheral surface of the through hole and one end surface are coated with a conductive material, the dielectric coaxial resonator has an axial direction. Since the dimension is made longer than the predetermined dimension based on the wavelength of the resonance frequency, and the inner peripheral surface and the outer peripheral surface are covered with the conductive material by the predetermined dimension based on the wavelength of the resonance frequency from the one end, the resonance frequency Regardless, the external dimensions of the dielectric coaxial resonator can be standardized to the same dimension.

As a result, when applied to a dielectric filter or the like in which a plurality of dielectric coaxial resonators having different resonance frequencies are connected in series, the dielectric coaxial resonators can be easily arranged and installed, and the storage space can be effectively utilized. be able to.

Further, according to the present invention, a dielectric having an axial dimension longer than a predetermined dimension based on the wavelength of the resonance frequency is dipped from the lower end into the bath of the conductive coating material by the predetermined dimension, and one end surface thereof is Since the conductive coating material is applied to the inner and outer peripheral surfaces and then heated at a predetermined firing temperature to form the conductive coating layer, the axial dimension of the conventional dielectric is adjusted. The polishing process for this is unnecessary, the manufacturing process is simplified by this amount, and the manufacturing can be automated.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a dielectric coaxial resonator manufactured by an electrode forming method according to the present invention.

FIG. 2 is a vertical cross-sectional view of a first embodiment of a dielectric coaxial resonator manufactured by an electrode forming method according to the present invention.

FIG. 3 is a schematic view showing an electrode forming method according to the present invention,
(A) is a diagram showing a state before the dielectric is immersed in the coating material tank, (b) is a diagram showing a state in which the dielectric is immersed in the coating material tank, and (c) is a diagram showing the dielectric being immersed in the coating material tank Showing a state in which the atmospheric pressure is raised in the state of being kept, (d) is a diagram showing a state in which the atmospheric pressure is lowered in a state where the dielectric is pulled up from the coating material tank,
(E) is a figure which shows the baking process of the electroconductive coating material apply | coated to the dielectric material.

FIG. 4 is a diagram showing the state of the liquid surface of the conductive coating material, (a)
FIG. 4 is a diagram showing a state of the liquid surface of the conductive coating material when the dielectric is immersed, and (b) is a diagram showing a state of the liquid surface of the conductive coating material when the atmospheric pressure is increased.

FIG. 5 is a plan view showing the internal structure of a dielectric filter using the dielectric coaxial resonator according to the first embodiment.

FIG. 6 is a perspective view showing an example of a structure of a dielectric coaxial resonator using a dielectric having a non-through hole.

FIG. 7 is a vertical sectional view of a dielectric coaxial resonator using a dielectric having a non-through hole.

FIG. 8 is an equivalent circuit diagram of a dielectric coaxial resonator using a dielectric having a non-through hole.

FIG. 9 is a perspective view showing a first embodiment of an integrally molded dielectric filter manufactured by the electrode forming method according to the present invention.

FIG. 10 is a vertical cross-sectional view of a first embodiment of an integrally molded dielectric filter manufactured by the electrode forming method according to the present invention.

FIG. 11 is an equivalent circuit diagram of a first embodiment of an integrally molded dielectric filter manufactured by the electrode forming method according to the present invention.

FIG. 12 is a perspective view showing a second embodiment of an integrally molded dielectric filter manufactured by the electrode forming method according to the present invention.

FIG. 13 is a vertical cross-sectional view of a second embodiment of an integrally molded dielectric filter manufactured by the electrode forming method according to the present invention.

FIG. 14 is a diagram showing a state in which a dielectric having a coupling hole with a small diameter is immersed in a paste tank.

FIG. 15 is a perspective view showing a conventional dielectric coaxial resonator.

FIG. 16 is a view showing a manufacturing process of a conventional dielectric coaxial resonator, (a) is a process drawing of immersing the dielectric in a coating material tank,
(B) is a process drawing of firing a conductive coating material applied to a dielectric, and (c) is a process drawing of polishing a dielectric having a metal film formed thereon.

FIG. 17 is a plan view showing a schematic structure of a dielectric filter using a conventional dielectric coaxial resonator.

[Explanation of symbols]

 1,10 Dielectric coaxial resonator 2,11,21,30 Dielectric 3,12,22,23 Hole 4 Electrode 5 Sealed container 6 Pump 7 Electrode paste 8 Paste tank 9 Furnace 13 Inner conductor electrode 14 Outer conductor electrode 15, 16, 24, 25 Terminal electrode 20, 20 'Dielectric filter 31, 32 hole 33 Coupling hole

Claims (2)

[Claims] 1. An outer peripheral surface parallel to the axis of a columnar dielectric having one or more axially extending holes, an inner peripheral surface of the hole and at least one end surface provided with the hole are coated with a conductive material. In the dielectric coaxial resonator, the dielectric has an axial dimension longer than a predetermined dimension based on the wavelength of the resonance frequency, and the inner peripheral surface and the outer peripheral surface of the dielectric have the predetermined dimension from the end surface. A dielectric coaxial resonator, characterized in that it is covered with the conductive material only. 2. The dielectric is vertically arranged by closing the upper end of the hole above the conductive material tank containing the liquid conductive material.
A first step of applying the conductive material to the lower end surface and the outer peripheral surface of the dielectric body by immersing the dielectric body in the tank under a first atmospheric pressure by a predetermined dimension based on the wavelength of the resonance frequency; and A second step of applying the conductive material to the inner peripheral surface of the dielectric material by the predetermined dimension while raising the atmospheric pressure to a predetermined second atmospheric pressure higher than the first atmospheric pressure while being immersed in the conductive material tank. And a third step of firing a dielectric material coated with a conductive material at a predetermined high temperature to form a conductive coating film, the conductivity of the dielectric coaxial resonator according to claim 1. Film forming method.