Ka wave band flexible transmission transition device

Abstract

The utility model provides a Ka wave band flexible transmission transition device which comprises a microwave printed board, a ceramic substrate, a coaxial connector insulator, an insulator inner conductor which is connected inside the coaxial connector insulator and extends towards the ceramic substrate, a gold belt ring which is connected outside the insulator inner conductor, and a ceramic-based microstrip line which is connected on the upper surface of the ceramic substrate. The gold strip is connected with the ceramic-based microstrip line; and the coplanar microstrip line is connected to the upper surface of the microwave printed board. According to the utility model, high-performance transmission of radio frequency signals in frequency bands of Ka and below can be realized, and the interface transmission performance and the product assembly consistency of a microwave assembly product are effectively guaranteed; especially, the hard transmission lines are flexibly connected in a manner of welding a reverse gold belt ring through electric resistance and directly lapping a gold belt, so that the problems of poor transmission performance and poor stress matching caused by tin soldering in a traditional transition device are avoided, and the assembly consistency of micro-assembly products is improved. And a high-performance and reliable radio frequency flexible transmission transition device is provided for the microwave assembly.

Description

Technical Field

[0001] This utility model relates to the field of electronic components technology, specifically to a Ka-band flexible transmission transition device. Background Technology

[0002] In microwave component products, signals are typically routed from the printed circuit board (PCB) to the outside via RF coaxial connectors. The inner conductor of the coaxial connector's insulator needs to form an electrical interconnect with the PCB transmission line. Coaxial connectors are two-conductor conduction systems with a TEM mode transmission mode; microstrip lines are planar transmission lines with a mixed mode transmission mode. Because the longitudinal field component is much smaller than the transverse field component, the microstrip line transmission mode characteristics are close to the quasi-TEM mode. With appropriate transition devices, the interconnection between coaxial connectors and microstrip lines can achieve good transmission characteristics.

[0003] Existing transmission transition devices of this type mainly use two forms. First, the inner conductor of the coaxial connector insulator is rigidly connected to the microstrip line pads on the printed circuit board using solder. Second, the inner conductor of the coaxial connector insulator is softly connected to the microstrip line pads using solder via an omega-3 gold strip. The first form has better mechanical strength but is prone to stress mismatch during operation, posing a risk of failure. The second form, due to the presence of the omega-3 gold strip, has better stress matching, but due to the complexity of the device and the use of solder in multiple places, it is difficult to control assembly consistency during production. Furthermore, the use of solder in both forms introduces several factors that negatively impact transmission performance. Solder usage, solder joint interface quality, number of solder voids, solder wetting angle, and the length of the inner conductor that is wetted all affect reliability and transmission performance.

[0004] Chinese Patent Publication No. CN 114083169, with the patentee being the Shanghai Radio Equipment Research Institute, and the publication date being July 4, 2023, entitled "Soft Connection Process Method and Tooling for Radio Frequency Coaxial to Microstrip," discloses a soft connection process method and tooling for radio frequency coaxial to microstrip. The shortcomings of this invention are that the device is complex and uses two solder joints to achieve electrical interconnection. Issues such as solder joint interface quality, number of solder joint voids, solder joint wetting angle, and wetting length of the inner conductor are difficult to control, which can easily lead to deterioration of transmission performance. Furthermore, it is impossible to guarantee assembly consistency during mass production.

[0005] Therefore, a transmission transition device that balances signal transmission performance, connection reliability, and assembly consistency is needed. Summary of the Invention

[0006] This invention addresses the technical problem of existing technologies failing to simultaneously achieve optimal signal transmission performance, connection reliability, and assembly consistency. It provides a Ka-band flexible transmission transition device that flexibly connects various transmission lines using reverse-lapped gold strip rings and direct resistance-bonded gold strips, ultimately allowing the transmission lines to enter the printed circuit board as coplanar microstrip lines. This invention achieves low insertion loss and low return loss signal transmission in the Ka and lower bands while maintaining good assembly consistency.

[0007] This utility model provides a Ka-band flexible transmission transition device, including a microwave printed circuit board, a ceramic substrate, a coaxial connector insulator arranged in sequence, an inner conductor of the insulator connected inside the coaxial connector insulator and extending into the ceramic substrate, a gold strip ring connected outside the inner conductor of the insulator, a ceramic-based microstrip line connected to the upper surface of the ceramic substrate, a strip-shaped gold strip connected to one end of the ceramic-based microstrip line, and a coplanar microstrip line connected to the upper surface of the microwave printed circuit board.

[0008] Gap is provided between the microwave printed circuit board and the ceramic substrate, and between the ceramic substrate and the coaxial connector insulator. The gold strip ring is a hollow ring. The inner conductor of the insulator is located above one side of the ceramic-based microstrip line. The outer wall of the inner conductor of the insulator is connected to the inner wall of the gold strip ring. The bottom of the outer wall of the gold strip ring is connected to the ceramic-based microstrip line. The other end of the strip gold strip is connected to the coplanar microstrip line.

[0009] In a preferred embodiment of the Ka-band flexible transmission transition device described in this utility model, the coplanar microstrip line includes a coplanar microstrip line impedance matching section and a coplanar microstrip line high-impedance section connected to a microwave printed circuit board, with the high-impedance section located on both sides of the coplanar microstrip line impedance matching section.

[0010] It also includes a coplanar microstrip line planar dielectric located between the impedance matching section and the high impedance section of the coplanar microstrip line, and the coplanar microstrip line planar dielectric is filled with air.

[0011] The strip gold strip is connected to the impedance matching section of the coplanar microstrip line.

[0012] In a preferred embodiment of the Ka-band flexible transmission transition device described in this utility model, the strip gold strip includes a gold strip, a first gold strip solder joint connected to one end of a ceramic-based microstrip line via resistance welding, and a second gold strip solder joint connected to one end of a coplanar microstrip line impedance matching section via resistance welding.

[0013] The Ka-band flexible transmission transition device described in this utility model, as a preferred embodiment, further includes a first air cavity located between the ceramic substrate and the coaxial connector insulator and a second air cavity located between the microwave printed circuit board and the ceramic substrate.

[0014] Both the first and second air cavities are quasi-coaxial air cavities.

[0015] In a preferred embodiment of the Ka-band flexible transmission transition device described in this utility model, the microwave printed circuit board is a resin board filled with two layers of ground-laid nano-ceramic material, and the ceramic substrate is made of alumina.

[0016] In a preferred embodiment of the Ka-band flexible transmission transition device described in this utility model, the coaxial connector insulator includes an insulating dielectric post, and the inner conductor of the insulator passes through the insulating dielectric post along the axial direction of the insulating dielectric post and extends to both ends.

[0017] In a preferred embodiment of the Ka-band flexible transmission transition device described in this utility model, the gold strip ring includes a first gold strip ring welded to a ceramic-based microstrip line via resistance welding and a second gold strip ring welded to an inner conductor of an insulator via resistance welding; the first gold strip ring weld is located below the second gold strip ring weld.

[0018] In a preferred embodiment of the Ka-band flexible transmission transition device described in this invention, the gold plating layer of the ceramic-based microstrip line and the coplanar microstrip line are on the same horizontal plane.

[0019] In the Ka-band flexible transmission transition device described in this utility model, as a preferred embodiment, the distance between the coaxial connector insulator and the ceramic substrate is 0.5 mm.

[0020] In a preferred embodiment of the Ka-band flexible transmission transition device described in this utility model, the gold strip ring is formed by rolling gold strips, with the two ends of the gold strips overlapping above the inner conductor of the insulator to form a ring with a diameter larger than that of the inner conductor of the insulator. The overlapping area of ​​the gold strip ring is fixed by resistance welding using a metal contact pressure welding machine.

[0021] This utility model has the following advantages:

[0022] This invention enables high-performance transmission of radio frequency signals in the Ka band and below, effectively ensuring the interface transmission performance and product assembly consistency of microwave component products. In particular, it uses resistance welding of reverse gold strip rings and direct overlapping of gold strips to flexibly interconnect the rigid transmission lines of each part, avoiding the problems of poor transmission performance and poor stress matching caused by soldering in traditional transition devices, and improving the assembly consistency of micro-assembled products. It provides a high-performance and reliable flexible radio frequency transmission transition device for microwave components. Attached Figure Description

[0023] Figure 1 This is a schematic diagram showing the positional relationship of a Ka-band flexible transmission transition device.

[0024] Figure 2 A front cross-sectional view of the assembly relationship of a Ka-band flexible transmission transition device;

[0025] Figure 3 A top view of the assembly relationship of a Ka-band flexible transmission transition device;

[0026] Figure 4 The insertion loss simulation curve of a Ka-band flexible transmission transition device is shown.

[0027] Figure 5 This is a simulation curve of the return loss of a Ka-band flexible transmission transition device.

[0028] Figure label:

[0029] 1. Microwave printed circuit board; 2. Ceramic substrate; 3. Coaxial connector insulator; 4. Inner conductor of insulator; 5. Gold strip ring; 51. First solder joint of gold strip ring; 52. Second solder joint of gold strip ring; 6. Ceramic-based microstrip line; 7. Strip gold strip; 71. First solder joint of gold strip; 72. Second solder joint of gold strip; 8. Coplanar microstrip line; 81. Impedance matching section of coplanar microstrip line; 82. High-resistance section of coplanar microstrip line; 9. Planar dielectric of coplanar microstrip line; 10. First air cavity; 11. Second air cavity. Detailed Implementation

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0031] Example 1

[0032] like Figures 1-3 As shown, a Ka-band flexible transmission transition device includes: a microwave printed circuit board 1, a ceramic substrate 2, a coaxial connector insulator 3, an inner conductor of the insulator 4, a gold strip ring 5, a ceramic-based microstrip line 6, a strip gold strip 7, a coplanar microstrip line 8, a coplanar microstrip line planar dielectric 9, a first air cavity 10, and a second air cavity 11.

[0033] Microwave printed circuit board 1 uses two layers of nano-ceramic filled resin material.

[0034] The ceramic substrate 2 uses alumina material.

[0035] Coplanar microstrip lines 8 are disposed on the upper surface of microwave printed circuit board 1;

[0036] The coaxial connector insulator 3 includes an insulating dielectric post and an inner conductor post 4. The inner conductor post 4 passes through the insulating dielectric post axially and extends outward at both ends.

[0037] The ceramic-based microstrip line 6 is disposed between the microwave printed circuit board 1 and the coaxial connector insulator 3, and the gold plating layer of the ceramic-based microstrip line 6 is on the same horizontal plane as the coplanar microstrip line 8.

[0038] One end of the inner conductor 4 is connected to the inner wall of the gold strip ring 5 by resistance welding, and the ceramic-based microstrip line 6 is connected to the outer wall of the gold strip ring 5 by resistance welding.

[0039] The ceramic-based microstrip line 6 and the coplanar microstrip line 8 are overlapped by a strip of gold tape 7 and fixed by resistance welding.

[0040] This invention uses spot welding of reverse gold strip ring 5 and direct overlapping of strip gold strip 7 to flexibly interconnect the various rigid transmission lines, avoiding the introduction of unstable factors that degrade transmission performance by using solder, and ensuring assembly consistency in mass production.

[0041] To ensure sufficient assembly space for the gold strip ring 5, a ceramic microstrip line 6 is added between the coaxial connector 3 and the microwave printed circuit board 1 as a transition.

[0042] To ensure transmission performance, the insulator 3 and the ceramic substrate 2 are placed with a 0.5mm gap to form a coaxial air cavity device.

[0043] The coplanar microstrip line 8 is a surface-printed line on the microwave printed circuit board 1. The planar dielectric 9 of the coplanar microstrip line is filled with air. At position 51, resistance welding is used to weld the outer wall of the gold strip ring 5 to the ceramic-based microstrip line 6. At position 52, resistance welding is used to weld the inner conductor 4 of the insulator to the inner wall of the gold strip ring 5. At position 71, resistance welding is used to weld the ceramic-based microstrip line 6 to the left end of the strip gold strip 7. At position 72, resistance welding is used to weld the right end of the strip gold strip 7 to the coplanar microstrip line. The coaxial connector insulator 3 maintains a certain distance from the ceramic substrate 2 to form an air cavity 10, and the ceramic substrate 2 maintains a certain distance from the microwave printed circuit board 1 to form an air cavity 11.

[0044] This invention uses a gold strip ring 5 and a strip gold strip 7 to resistance weld the various rigid transmission lines together, achieving flexible interconnection. Compared with traditional transition devices that rely on solder welding, this avoids the solder from degrading transmission performance and improves stress matching and assembly consistency. These conclusions have been verified by RF electromagnetic performance simulation results.

[0045] In order to ensure a good transition of radio frequency signals from the coaxial connector to the microstrip line, an air cavity needs to be constructed during the assembly process. The specific method is to maintain an assembly distance between the insulator 3 and the ceramic substrate 2 through simulation calculation, and to maintain a certain distance between the ceramic substrate 2 and the microwave printed circuit board 1.

[0046] To ensure the independent transmission performance of ceramic-based microstrip line 6 and coplanar microstrip line 8, appropriate linewidths and thicknesses were calculated and adopted based on the dielectric material.

[0047] To ensure good matching during transmission, a high-impedance section 82 is provided on the coplanar microstrip line; to adjust the overall characteristic impedance to 50 ohms, an impedance matching section 81 is provided on the coplanar microstrip line.

[0048] The assembly method in this embodiment is as follows:

[0049] Step S1: Use electromagnetic simulation software to optimize and obtain assembly parameters: the first air cavity 10 of the inner conductor of the coaxial connector insulator has a length of 0.5mm and a radius of 0.5mm; the second air cavity 11 of the strip gold strip 7 has a length of 0.15mm and a depth of 0.4mm; the gold strip ring 5 has a radius of 0.25mm; and the strip gold strip 7 has a span of 0.5mm and an arch height of 50um.

[0050] Step S2: Microwave printed circuit board 1 is prepared. One example is a 0.254mm nano-ceramic-filled microwave board with a dielectric constant of 2.94, and coplanar microstrip lines 8 with a thickness of 0.017mm, a width of 0.61mm, and a planar dielectric width of 0.3mm.

[0051] Step S3: Prepare ceramic substrate 2, one example being an alumina ceramic substrate with a dielectric constant of 9.8 and a thickness of 0.254 mm, and ceramic-based microstrip line 6 with a thickness of 0.017 mm and a width of 0.3 mm.

[0052] Step S4: The positional characteristics of the coaxial connector insulator 3 are that the vertical distance between the axis of the inner conductor 4 and the ceramic micro-base microstrip line 6 is 0.285mm, and the horizontal distance between the surface of the coaxial connector insulator 3 near the inner conductor 4 and the ceramic substrate 2 is 0.5mm.

[0053] Step S5: Prepare the gold strip for the gold strip ring 5. Take a gold strip that is 1.1 mm long and 25 μm thick, and place it symmetrically in the middle of the left pad of the ceramic microstrip line 6. Use a metal contact pressure welding machine to fix the resistance welding at the overlapping position of the gold strip of the gold strip ring 5 and the ceramic microstrip line 6.

[0054] Step S6: Prepare the gold strip 7. Take a gold strip that is 0.5 mm long and 25 μm thick. Place one end in the middle of the pad on the right side of the ceramic-based microstrip line 6 and the other end at the edge of the high-resistivity section 82 of the coplanar microstrip. Fix the resistance welding at the two positions where the gold strip and the two printed lines overlap using a metal contact welding machine.

[0055] Step S7: Roll up both ends of the gold strip used for the gold strip ring 5 towards the inner conductor 4 of the insulator. The two ends of the gold strip overlap above the inner conductor 4 of the insulator to form a gold strip ring 5 with a diameter slightly larger than the diameter of the inner conductor 4 of the insulator. Use a metal contact pressure welding machine to fix the resistance welding in the overlapping area.

[0056] Thus, the Ka-band flexible transmission transition device, which uses gold strip rings and gold strips to electrically interconnect the various rigid transmission lines, has completed its functional implementation.

[0057] The insertion loss simulation results of this embodiment are as follows: Figure 4 As shown in the figure, the simulation results of return loss are as follows: Figure 5 As shown, the Ka-band transmission performance is good.

[0058] In summary, compared with existing transmission conversion devices that use solder for electrical interconnection, the Ka-band flexible transmission transition device provided by this invention uses gold ribbon rings to resistance weld the inner conductor of the coaxial connector insulator to the ceramic-based microstrip line, and uses gold ribbon to resistance weld the ceramic-based microstrip line to the coplanar microstrip line, ensuring assembly consistency and good RF transmission performance. The overall device can achieve low insertion loss and low return loss signal transmission transition in the Ka and below frequency bands.

[0059] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A Ka-band flexible transmission transition device, characterized in that: The system includes a microwave printed circuit board (1), a ceramic substrate (2), a coaxial connector insulator (3) arranged in sequence, an inner conductor (4) of the insulator connected inside the coaxial connector insulator (3) and extending to the ceramic substrate (2), a gold strip ring (5) connected to the outside of the inner conductor (4), a ceramic-based microstrip line (6) connected to the upper surface of the ceramic substrate (2), a strip-shaped gold strip (7) connected to one end of the ceramic-based microstrip line (6), and a coplanar microstrip line (8) connected to the upper surface of the microwave printed circuit board (1). Gap is provided between the microwave printed circuit board (1) and the ceramic substrate (2), and between the ceramic substrate (2) and the coaxial connector insulator (3). The gold strip ring (5) is a hollow ring. The inner conductor (4) of the insulator is located above one side of the ceramic-based microstrip line (6). The outer wall of the inner conductor (4) of the insulator is connected to the inner wall of the gold strip ring (5). The bottom of the outer wall of the gold strip ring (5) is connected to the ceramic-based microstrip line (6). The other end of the strip gold strip (7) is connected to the coplanar microstrip line (8).

2. The Ka-band flexible transmission transition device according to claim 1, characterized in that: The coplanar microstrip line (8) includes a coplanar microstrip line impedance matching section (81) and a coplanar microstrip line high impedance section (82) connected to the microwave printed circuit board (1). The coplanar microstrip line high impedance section (82) is located on both sides of the coplanar microstrip line impedance matching section (81). It also includes a coplanar microstrip line planar dielectric (9) located between the coplanar microstrip line impedance matching section (81) and the coplanar microstrip line high impedance section (82), the coplanar microstrip line planar dielectric (9) being filled with air; The strip gold strip (7) is connected to the coplanar microstrip line impedance matching section (81).

3. The Ka-band flexible transmission transition device according to claim 2, characterized in that: The strip gold strip (7) includes a gold strip, a first gold strip solder joint (71) connected to one end of the ceramic-based microstrip line (6) by resistance welding, and a second gold strip solder joint (72) connected to one end of the gold strip by resistance welding to the impedance matching section (81) of the coplanar microstrip line.

4. The Ka-band flexible transmission transition device according to claim 1, characterized in that: It also includes a first air cavity (10) located between the ceramic substrate (2) and the coaxial connector insulator (3) and a second air cavity (11) located between the microwave printed circuit board (1) and the ceramic substrate (2); Both the first air cavity (10) and the second air cavity (11) are quasi-coaxial air cavities.

5. The Ka-band flexible transmission transition device according to claim 1, characterized in that: The microwave printed circuit board (1) is a resin board filled with two layers of ground-laid nano-ceramics, and the ceramic substrate (2) is made of alumina.

6. The Ka-band flexible transmission transition device according to claim 1, characterized in that: The coaxial connector insulator (3) includes an insulating dielectric post, and the inner conductor (4) of the insulator passes through the insulating dielectric post along the axial direction and extends to both ends.

7. The Ka-band flexible transmission transition device according to claim 1, characterized in that: The gold strip ring (5) includes a first gold strip ring weld point (51) connected to the ceramic-based microstrip line (6) by resistance welding and a second gold strip ring weld point (52) connected to the inner conductor (4) of the insulator by resistance welding; the first gold strip ring weld point (51) is located below the second gold strip ring weld point (52).

8. The Ka-band flexible transmission transition device according to claim 1, characterized in that: The gold plating layer of the ceramic-based microstrip line (6) is on the same horizontal plane as the coplanar microstrip line (8).

9. A Ka-band flexible transmission transition device according to claim 1, characterized in that: The distance between the coaxial connector insulator (3) and the ceramic substrate (2) is 0.5 mm.

10. A Ka-band flexible transmission transition device according to claim 1, characterized in that: The gold strip ring (5) is made of gold strip rolled up, and the two ends of the gold strip overlap above the inner conductor (4) of the insulator to form a ring with a diameter larger than the inner conductor (4) of the insulator. The overlapping area of ​​the gold strip ring (5) is fixed by resistance welding using a metal contact pressure welding machine.

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