Airtight seal radio frequency coaxial switch

Abstract

The invention discloses an air-tight seal radio frequency coaxial switch, which comprises a glass insulator assembly, a printed board assembly, an electromagnetic assembly, a microwave assembly, an inner conductor assembly, an outer cover and a cavity, and is characterized in that the glass insulator assembly and the cavity are respectively arranged at two ends of the outer cover, and the microwave assembly and the inner conductor assembly are arranged on the cavity; the printed board assembly and the electromagnetic assembly are arranged in the outer cover; the air-tight sealing problem of the product is solved, the performance is not influenced by the external environment, the performance is stable, and the reliability is high.

Description

Technical Field

[0001] The present invention relates to the technical field of radio frequency connectors, and in particular to an airtight radio frequency coaxial switch. Background Art

[0002] RF coaxial switches are primarily used in signal receiving and transmitting systems, switching RF channels and transmitting RF signals. These products are widely used in aerospace, sea-based, and land-based communications, electronic countermeasures, radar systems, network systems, automated control systems, and automated test equipment.

[0003] As product applications deepen, RF coaxial switches have exposed some shortcomings in some application scenarios. Since the conventional RF coaxial switches are enclosed (see Figure 10 ), sealed with non-metallic materials such as sealing rings or sealants, the gaps between their molecules are large. Under the repeated "condensation" and "breathing" caused by temperature cycling, the inside of the switch will exchange atmosphere with the outside world. If the switch is in a low temperature and high humidity environment, the condensation layer between the RF contacts will deteriorate the insertion loss index; working in a salt spray environment will cause the switch action mechanism to jam and the RF contacts to be unable to contact; in a low pressure environment, the internal thermal conductivity of the switch will be reduced, vacuum micro-discharge and vacuum cold welding will occur, causing the switch power breakdown damage or failure to switch normally. Summary of the Invention

[0004] The main purpose of the present invention is to provide a hermetically sealed radio frequency coaxial switch, aiming to solve the existing technical problems.

[0005] To achieve the above objectives, the present invention provides a hermetic radio frequency coaxial switch, comprising a glass insulator assembly, a printed circuit board assembly, an electromagnetic assembly, a microwave assembly, an inner conductor assembly, an outer cover, and a cavity. The glass insulator assembly and the cavity are respectively arranged at two ends of the outer cover, the microwave assembly and the inner conductor assembly are arranged on the cavity, and the printed circuit board assembly and the electromagnetic assembly are arranged in the outer cover.

[0006] Furthermore, the glass insulator component at the low frequency end and the insulating support in the inner conductor component at the radio frequency end are made by glass sintering.

[0007] Furthermore, laser welding is used between the glass insulator assembly and the outer cover, and between the outer cover and the cavity, and brazing is used between the inner conductor assembly and the cavity.

[0008] Furthermore, the glass insulator assembly includes a shell, a terminal is provided on the shell, and a first glass insulator is provided around the terminal. The terminal is made of 4J50 material, the first glass insulator is made of glass powder ELAN13# material, and the shell is made of SUS304 stainless steel.

[0009] Furthermore, the inner conductor assembly includes an inner conductor, a second glass insulator is provided on the outer side of the inner conductor, and an outer conductor is provided on the outer side of the second glass insulator, wherein the second glass insulator is sintered using glass powder BH-GK.

[0010] Furthermore, the surface of the cavity where the outer conductor of the inner conductor assembly fits together is partially plated with gold, and the inner conductor assembly is entirely plated with gold.

[0011] Furthermore, a second boss is provided at the connection between the cavity and the outer cover, and a second heat-insulating groove is processed between the second boss and the second glass insulator.

[0012] Furthermore, a first boss is provided at the connection between the shell and the outer cover, and a first heat-insulating groove is processed between the first boss and the first glass insulator.

[0013] Furthermore, a double material storage tank is processed on the cavity, and the double material storage tank consists of two annular cavities. The annular cavity and the inner hole surface of the cavity that cooperates with the outer conductor are partially gold-plated, and a gap of +0.025mm to +0.06mm is left at the cooperation between the outer conductor and the cavity.

[0014] The beneficial effects of the present invention are embodied in: The invention solves the problem of product airtightness, and its performance is not affected by the external environment, and it has stable performance and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of the hermetic radio frequency coaxial switch of the present invention; Figure 2 For the present invention Figure 1 Bottom view; Figure 3 For the present invention Figure 1 Top view; Figure 4 This is a schematic structural diagram of a glass insulator assembly according to the present invention; Figure 5 This is a schematic structural diagram of the inner conductor assembly of the present invention; Figure 6 This is a schematic structural diagram of the first heat-conducting boss and the first heat-insulating groove of the present invention; Figure 7 This is a schematic structural diagram of the second heat-conducting boss and the second heat-insulating groove of the present invention; Figure 8 This is a schematic diagram of the storage tank structure of the present invention; Figure 9 This is a schematic structural diagram of the double-female adapter of the present invention; Figure 10 This is the existing RF coaxial switch packaging form.

[0016] Description of reference numerals: 1. Glass insulator assembly; 11. Housing; 12. Terminal; 13. First glass insulator; 2. Printed circuit board assembly; 3. Electromagnetic assembly; 4. Microwave assembly; 5. Inner conductor assembly; 51. Inner conductor; 52. Second glass insulator; 53. Outer conductor; 6. Outer cover; 7. Cavity; 8. Second boss; 9. Second thermal insulation groove; 10. First boss; 13. First glass insulator; 14. First thermal insulation groove; 15. Double material storage trough. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0018] See also Figure 1-3 The present invention provides an airtight radio frequency coaxial switch, comprising a glass insulator assembly 1, a printed circuit board assembly 2, an electromagnetic assembly 3, a microwave assembly 4, an inner conductor assembly 5, an outer cover 6, and a cavity 7. The glass insulator assembly 1 and the cavity 7 are respectively arranged at both ends of the outer cover 6, the microwave assembly 4 and the inner conductor assembly 5 are arranged on the cavity 7, and the printed circuit board assembly 2 and the electromagnetic assembly 3 are arranged in the outer cover 6.

[0019] In this embodiment, the drive signal is led out to the printed circuit board assembly through the glass insulator assembly, and the rated control drive signal is applied to the product electromagnetic assembly through the printed circuit board assembly. The armature in the electromagnetic assembly changes state and drives the microwave assembly, completing signal switching, and finally outputting power through the inner conductor assembly.

[0020] In one embodiment, the insulating supports in the glass insulator component 1 at the low frequency end and the inner conductor component 5 at the radio frequency end are made by glass sintering.

[0021] In one embodiment, laser welding is used between the glass insulator assembly 1 and the outer cover 6 , and between the outer cover 6 and the cavity 7 , and brazing is used between the inner conductor assembly 5 and the cavity 7 .

[0022] In one embodiment, see Figure 4The glass insulator assembly 1 includes a housing 11, a terminal 12 disposed on the housing 11, and a first glass insulator 13 disposed around the terminal 12. The terminal 12 is made of 4J50 material, and the first glass insulator 13 is made of ELAN13# glass frit. The housing 11 is constructed of SUS304 stainless steel. The glass frit and the terminal material have similar thermal expansion coefficients to the stainless steel, ensuring that the glass is less susceptible to cracking during sintering.

[0023] In one embodiment, see Figure 5 The inner conductor assembly 5 includes an inner conductor 51, a second glass insulator 52 disposed outside the inner conductor 51, and an outer conductor 53 disposed outside the second glass insulator 52. The second glass insulator 52 is sintered using BH-14GK glass frit. BH-14GK has a relatively low relative dielectric constant of 4.0-4.1 among glass materials, which facilitates excellent RF performance. Its coefficient of expansion is similar to that of the 4J29 material used for the inner and outer conductors, making it less susceptible to cracking after sintering.

[0024] In one embodiment, the cavity 7 and the outer conductor of the inner conductor assembly 5 are partially gold-plated at their joints, and the inner conductor assembly 5 is entirely gold-plated, making the two more suitable for brazing.

[0025] In one embodiment, see Figure 6 A second boss 8 is provided at the connection between the cavity 7 and the outer cover 6 , and a second insulation groove 9 is processed between the second boss 8 and the second glass insulator 52 .

[0026] See also Figure 7 A first boss 10 is provided at the connection between the shell 11 and the outer cover 6 , and a first insulation groove 14 is processed between the first boss 10 and the first glass insulator 13 .

[0027] This structure forms a solid boss with a cross-section of 0.8mm high and 0.6mm wide between two metals. The height of the solid boss is greater than its width, and a thermal insulation groove is machined between the solid boss and the glass insulator. The two metal bosses and fillets are transitional fits, ensuring a small gap between the two welded metals, with a maximum gap of no more than 0.02mm and a maximum interference of no more than 0.015mm. This can reduce stress after assembly. This structure helps concentrate heat at the weld, achieving a good penetration depth, increasing the distance heat is transferred to the glass insulator, reducing the impact of heat on the glass insulator, and thus improving leakage performance.

[0028] In one embodiment, see Figure 8 A double material storage tank 15 is processed on the cavity 7. The double material storage tank 15 consists of two annular cavities. The annular cavity and the inner hole surface of the cavity that cooperates with the outer conductor 53 are partially gold-plated. A gap of +0.025mm to +0.06mm is left at the cooperation between the outer conductor 53 and the cavity 7.

[0029] Specifically, the cavity is machined with dual reservoirs measuring φ5.5×φ6.7×0.6 and φ5.5×φ6.5×0.5, respectively. These reservoirs consist of two annular cavities. The annular cavities and the inner surface of the cavity that mates with the outer conductor are partially gold-plated. To prevent stress damage to the glass insulator during assembly, a gap of +0.025mm to +0.06mm is left between the outer conductor and the cavity. Ring-shaped tin solder is placed in the upper reservoir. During brazing, liquid solder fills the gap between the outer conductor and the cavity. The lower reservoir effectively prevents solder from overflowing and flowing into the glass insulator surface within the cavity, improving insulation, voltage resistance, leakage rate, and RF performance.

[0030] Strict contamination control is required within the switch. For example, all parts are cleaned, vacuum-evacuated, and baked at high temperatures. Laser welding is performed using 99.99% high-purity nitrogen, ensuring a moisture content of no more than 18 ppm. The process sequence is as follows: brazing the cavity and inner conductor assembly, then laser-sealing the cavity and outer cover. Finally, the laser welding chamber is vacuumed and purged with high-purity nitrogen for three cycles. Once the moisture content falls below the required level, laser welding of the outer cover to the glass insulator assembly is completed.

[0031] See also Figure 9 The hermetic sealed RF coaxial switch can be directly soldered on the microstrip line, and can also be converted to a 2.92mm-F coaxial connector through a double female adapter. Figure 8 , connect to 3.5, 2.92, SMA and other interfaces.

[0032] It should be noted that if the embodiments of the present invention involve directional indications such as up, down, left, right, front, back, etc., then the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture as shown in the accompanying drawings. If the specific posture changes, the directional indication will also change accordingly.

[0033] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or schemes in which A and B are satisfied at the same time. In addition, "multiple" refers to more than two. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A hermetically sealed radio frequency coaxial switch, characterized in that , comprising a glass insulator assembly (1), a printed circuit board assembly (2), an electromagnetic assembly (3), a microwave assembly (4), an inner conductor assembly (5), an outer cover (6) and a cavity (7), wherein the glass insulator assembly (1) and the cavity (7) are respectively arranged at two ends of the outer cover (6), the microwave assembly (4) and the inner conductor assembly (5) are arranged on the cavity (7), and the printed circuit board assembly (2) and the electromagnetic assembly (3) are arranged in the outer cover (6).

2. The hermetic radio frequency coaxial switch according to claim 1, wherein: The insulating supports in the glass insulator component (1) at the low frequency end and the inner conductor component (5) at the radio frequency end are formed by glass sintering.

3. The hermetic radio frequency coaxial switch according to claim 1, wherein: Laser welding is used between the glass insulator assembly (1) and the outer cover (6), and between the outer cover (6) and the cavity (7), and brazing is used between the inner conductor assembly (5) and the cavity (7).

4. The hermetic radio frequency coaxial switch according to claim 1, wherein: The glass insulator assembly (1) comprises a shell (11), a terminal (12) is provided on the shell (11), and a first glass insulator (13) is provided on the periphery of the terminal (12), wherein the terminal (12) is made of 4J50 material, the first glass insulator (13) is made of glass powder ELAN13# material, and the shell (11) is made of SUS304 stainless steel.

5. The hermetic radio frequency coaxial switch according to claim 1, wherein: The inner conductor assembly (5) comprises an inner conductor (51), a second glass insulator (52) is provided on the outer side of the inner conductor (51), and an outer conductor (53) is provided on the outer side of the second glass insulator (52), wherein the second glass insulator (52) is sintered using glass powder BH-14GK.

6. The hermetic radio frequency coaxial switch according to claim 1, wherein: The surface of the cavity (7) where it fits with the outer conductor of the inner conductor assembly (5) is partially plated with gold, and the inner conductor assembly (5) is entirely plated with gold.

7. The hermetic radio frequency coaxial switch according to claim 5, characterized in that: A second boss (8) is provided at the connection between the cavity (7) and the outer cover (6), and a second heat-insulating groove (9) is processed between the second boss (8) and the second glass insulator (52).

8. The hermetic radio frequency coaxial switch according to claim 4, characterized in that: A first boss (10) is provided at the connection between the shell (11) and the outer cover (6), and a first heat-insulating groove (14) is processed between the first boss (10) and the first glass insulator (13).

9. The hermetic radio frequency coaxial switch according to claim 5, characterized in that: A double material storage tank (15) is processed on the cavity (7), and the double material storage tank (15) consists of two annular cavities. The annular cavity and the inner hole surface of the cavity that matches the outer conductor (53) are partially gold-plated, and a gap of +0.025mm to +0.06mm is left at the matching position between the outer conductor (53) and the cavity (7).

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