Low dielectric constant waveguide interface sealing structure and preparation method thereof

Abstract

The invention relates to a low dielectric constant waveguide interface sealing structure and a preparation method thereof, the dielectric constant of a metal glass sealing structure provided by the invention is 2-4, and the metal glass sealing structure can be used for a waveguide interface of a waveguide transmission device. The preparation method of the metal glass sealing structure comprises the following steps that S1, the metal shell is prepared from kovar alloy; s2, dewaxing is conducted on the pressed glass bead blanks, and glass beads without thorough dewaxing are obtained by reducing the roasting temperature; and S3, sintering and sealing the glass beads prepared in the S2 and the metal shell, and controlling the number and size of bubbles by regulating and controlling the sintering temperature in the sintering process to prepare the product. Compared with the prior art, the metal glass sealing structure prepared by the invention is low in dielectric constant and good in sealing performance, and can meet the characteristic impedance required by a miniaturized waveguide tube.

Description

Technical Field

[0001] The invention relates to the field of microwaves, and in particular to a low dielectric constant waveguide interface sealing structure and a preparation method thereof. Background Art

[0002] With the growing demand for miniaturization of microwave products and the continuous reduction of product size, the design and manufacturing requirements for waveguide interface components are becoming increasingly higher. As a key node in signal transmission, the precise matching of the characteristic impedance of the waveguide interface is essential to ensure the integrity of the signal. In the waveguide interface of the metal glass sealing structure, the dielectric constant of the glass medium is a key parameter that determines the characteristic impedance.

[0003] At present, the minimum dielectric constant of glass dielectric is 4.0. This value means in transmission line theory that in order to maintain the same characteristic impedance, a larger waveguide size is required to provide the necessary capacitance and inductance. This limitation poses a challenge to the miniaturization of waveguides. In order to achieve a miniaturized waveguide, the required characteristic impedance can only be achieved if the dielectric constant of the glass dielectric is smaller. Therefore, it is urgent to develop a glass dielectric material with a lower dielectric constant that can achieve the miniaturization of the waveguide while maintaining the required characteristic impedance, which has important practical significance for promoting the miniaturization of electronic devices. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a low dielectric constant waveguide interface sealing structure. By removing the air bubbles generated during the high-temperature sealing of the glass beads and the metal shell from which the wax is not completely removed, a metal-glass sealing structure with a dielectric constant smaller than that of the glass medium is obtained to meet the requirements of the characteristic impedance of a small waveguide tube.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] The present invention provides a low dielectric constant waveguide interface sealing structure, which is used for the waveguide interface of a waveguide transmission device, and comprises glass beads from which wax is not completely removed and a metal shell, wherein the shape of the inner periphery of the metal shell is adapted to the shape of the outer periphery of the glass beads, and the metal shell is fixedly sleeved on the outer periphery of the glass beads;

[0007] The interior of the glass beads contains a small amount of paraffin wax that has not been discharged in time;

[0008] The sealing structure is a metallic glass sealing structure.

[0009] Further preferably, the metal shell is Kovar alloy.

[0010] The present invention also provides a method for preparing the low dielectric constant waveguide interface sealing structure as described above, comprising the following steps:

[0011] S1: machining the Kovar alloy and performing a pre-oxidation treatment to obtain a metal shell;

[0012] S2: placing the pressed glass bead blank in a wax removal furnace, lowering the baking temperature during wax removal, so that a small amount of wax that has not been removed in time remains in the center of the glass bead blank, thereby obtaining glass beads with incomplete wax removal;

[0013] S3: Assemble the glass beads from which the wax is not completely removed obtained in S2 and the metal shell in a first mold; the metal shell is sintered and fixed to the periphery of the glass beads; during the sintering process, the sintering temperature is adjusted to control the number and size of bubbles, thereby obtaining a metal-glass sealing structure.

[0014] Furthermore, in S1, the machining includes turning, milling, drilling and grinding to increase the precision of the metal shell.

[0015] Furthermore, in S2, the preparation step of the glass bead blank includes: using glass powder with a dielectric constant of 4.0 to 4.1, pouring it into a metal mold for pressing and molding, and obtaining the glass bead blank.

[0016] Further preferably, in S2, the glass powder includes paraffin wax.

[0017] More preferably, in S2, the calcination temperature is 350-450°C.

[0018] During the wax removal process, as the roasting temperature continues to rise, the paraffin melts before the glass bead blank to form a fluid, and then the paraffin liquid gradually evaporates. However, since the roasting temperature does not continue to rise, the wax is not completely removed from the center of the glass bead blank.

[0019] Further preferably, in S3, the first mold is a graphite mold.

[0020] More preferably, in S3, the sintering temperature is 970-1000°C.

[0021] Kovar alloy is pre-oxidized before sealing to form a dense oxide film on the metal surface. During the sintering process, the formed glass beads quickly soften and melt again, so that the oxides in the glass beads and the oxide film on the metal surface fuse at high temperature, thereby improving the sealing between the glass beads and the metal shell.

[0022] Furthermore, in S3, the number and size of the bubbles are inversely proportional to the dielectric constant of the metallic glass sealing structure. When the dielectric constant of the metallic glass sealing structure decreases, the proportion of the number and size of the bubbles to the total volume of the metallic glass sealing structure increases accordingly.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) In the process of removing wax, the present invention reduces the sintering temperature so that the bubbles inside the glass beads are not fully removed, and adjusts the sintering temperature to control the number and size of the bubbles when the metal shell and the glass beads are sintered and fixed, thereby obtaining a metal-glass sealing structure with a low dielectric constant and good sealing performance.

[0025] (2) The dielectric constant of the metallic glass sealing structure provided by the present invention is 2 to 4, which can be applied to the waveguide interface of the waveguide transmission device and can meet the characteristic impedance required by the miniaturized waveguide tube. It has important practical significance for promoting the miniaturization of electronic equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A cross-sectional view of a low dielectric constant waveguide interface sealing structure of the present invention;

[0027] Figure 2 It is a top view of the low dielectric constant waveguide interface sealing structure of the present invention.

[0028] Reference numerals: 1 - metal shell, 2 - glass beads, 3 - air bubbles. DETAILED DESCRIPTION

[0029] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Any features such as preparation means, materials, structures or composition ratios not clearly described in this technical solution are regarded as common technical features disclosed in the prior art.

[0030] The dielectric constant of the glass powder in the embodiment of the present invention is 4.0-4.1.

[0031] Example 1

[0032] The present invention provides a method for preparing a low dielectric constant waveguide interface sealing structure, comprising the following steps:

[0033] S1: machining the Kovar alloy, and obtaining a metal shell 1 through continuous turning, milling, drilling, grinding and pre-oxidation treatment;

[0034] S2: Use glass powder with a dielectric constant of 4.0 to 4.1, pour it into a metal mold and press it into shape to obtain a glass bead blank; place the pressed glass bead blank in a wax removal furnace, and the baking temperature during wax removal is 350°C, so that a small amount of paraffin wax is not removed in time at the center of the glass bead blank, and obtain glass bead 2 with incomplete wax removal;

[0035] S3: Assemble the glass beads 2 with incomplete wax removal prepared in S2 and the metal shell 1 in a graphite mold, and sinter the metal shell 1 to be fixed on the outer periphery of the glass beads 2. During the sintering process, the sintering temperature is adjusted to 970°C to control the number and size of the bubbles 3, thereby obtaining a metal glass sealing structure.

[0036] Example 2

[0037] The present invention provides a method for preparing a low dielectric constant waveguide interface sealing structure, comprising the following steps:

[0038] S1: machining the Kovar alloy, and obtaining a metal shell 1 through continuous turning, milling, drilling, grinding and pre-oxidation treatment;

[0039] S2: Use glass powder with a dielectric constant of 4.0 to 4.1, pour it into a metal mold and press it into shape to obtain a glass bead blank; place the pressed glass bead blank in a wax removal furnace, and the baking temperature during wax removal is 350°C, so that a small amount of paraffin wax is not removed in time at the center of the glass bead blank, and obtain glass bead 2 with incomplete wax removal;

[0040] S3: Assemble the glass beads 2 and metal shell 1 prepared in S2 in a graphite mold. The metal shell 1 is sintered and fixed on the outer periphery of the glass beads 2. During the sintering process, the sintering temperature is adjusted to 1000°C to control the number and size of the bubbles 3 to obtain a metal glass sealing structure.

[0041] Example 3

[0042] The present invention provides a method for preparing a low dielectric constant waveguide interface sealing structure, comprising the following steps:

[0043] S1: machining the Kovar alloy, and obtaining a metal shell 1 through continuous turning, milling, drilling, grinding and pre-oxidation treatment;

[0044] S2: Use glass powder with a dielectric constant of 4.0 to 4.1, pour it into a metal mold and press it into shape to obtain a glass bead blank; place the pressed glass bead blank in a wax removal furnace, and the baking temperature during wax removal is 450°C, so that a small amount of paraffin wax is not removed in time at the center of the glass bead blank, and obtain glass bead 2 with incomplete wax removal;

[0045] S3: Assemble the glass beads 2 and metal shell 1 prepared in S2 in a graphite mold. The metal shell 1 is sintered and fixed to the outer periphery of the glass beads 2. During the sintering process, the sintering temperature is adjusted to 970°C to control the number and size of the bubbles 3 to obtain a metal glass sealing structure.

[0046] Example 4

[0047] The present invention provides a method for preparing a low dielectric constant waveguide interface sealing structure, comprising the following steps:

[0048] S1: machining the Kovar alloy, and obtaining a metal shell 1 through continuous turning, milling, drilling, grinding and pre-oxidation treatment;

[0049] S2: Use glass powder with a dielectric constant of 4.0 to 4.1, pour it into a metal mold and press it into shape to obtain a glass bead blank; place the pressed glass bead blank in a wax removal furnace, and the baking temperature during wax removal is 450°C, so that a small amount of paraffin wax is not removed in time at the center of the glass bead blank, and obtain glass bead 2 with incomplete wax removal;

[0050] S3: Assemble the glass beads 2 and metal shell 1 prepared in S2 in a graphite mold. The metal shell 1 is sintered and fixed on the outer periphery of the glass beads 2. During the sintering process, the sintering temperature is adjusted to 1000°C to control the number and size of the bubbles 3 to obtain a metal glass sealing structure.

[0051] The metallic glass sealing structure finally obtained in Examples 1-4 has good sealing performance and a dielectric constant between 2 and 4, which can meet the characteristic impedance required by the miniaturized waveguide.

[0052] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A low dielectric constant waveguide interface sealing structure, used for the waveguide interface of a waveguide transmission device, characterized in that: It comprises glass beads from which wax is not completely removed and a metal shell, wherein the shape of the inner circumference of the metal shell is adapted to the shape of the outer circumference of the glass beads, and the metal shell is fixedly sleeved on the outer circumference of the glass beads; The interior of the glass beads contains a small amount of paraffin wax that has not been discharged in time; The sealing structure is a metallic glass sealing structure.

2. A low dielectric constant waveguide interface sealing structure according to claim 1, characterized in that: The metal shell is made of Kovar alloy.

3. A method for preparing a low dielectric constant waveguide interface sealing structure as claimed in claim 1, characterized in that: The following steps are involved: S1: machining the Kovar alloy and performing a pre-oxidation treatment to obtain a metal shell; S2: performing wax removal treatment on the pressed glass bead blanks, lowering the calcination temperature, so that a small amount of paraffin wax that has not been removed in time is retained in the center of the glass bead blanks, thereby obtaining glass beads with incomplete wax removal; S3: Assemble the glass beads from which the wax is not completely removed obtained in S2 and the metal shell in a first mold; the metal shell is sintered and fixed to the periphery of the glass beads; during the sintering process, the sintering temperature is adjusted to control the number and size of bubbles, thereby obtaining a metal-glass sealing structure.

4. The method for preparing a low dielectric constant waveguide interface sealing structure according to claim 3, characterized in that: In S1, the machining includes turning, milling, drilling and grinding.

5. The method for preparing a low dielectric constant waveguide interface sealing structure according to claim 3, characterized in that: In S2, the preparation step of the glass bead blank comprises: using glass powder with a dielectric constant of 4.0 to 4.1, pouring it into a metal mold for pressing and molding, and obtaining the glass bead blank.

6. The method for preparing a low dielectric constant waveguide interface sealing structure according to claim 5, characterized in that: In S2, the glass powder includes paraffin wax.

7. The method for preparing a low dielectric constant waveguide interface sealing structure according to claim 3, characterized in that: In S2, the calcination temperature is 350-450°C.

8. The method for preparing a low dielectric constant waveguide interface sealing structure according to claim 3, characterized in that: In S3, the first mold is a graphite mold.

9. The method for preparing a low dielectric constant waveguide interface sealing structure according to claim 3, characterized in that: In S3, the sintering temperature is 970-1000°C.

10. The method for preparing a low dielectric constant waveguide interface sealing structure according to claim 3, characterized in that: In S3, the number and size of the bubbles are inversely proportional to the dielectric constant of the metallic glass sealing structure. When the dielectric constant of the metallic glass sealing structure decreases, the proportion of the number and size of the bubbles to the total volume of the metallic glass sealing structure increases accordingly.

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