Radio frequency cable interconnect structure and method for microwave assemblies

Abstract

This invention discloses an interconnection structure and method for radio frequency (RF) cables in microwave components. The RF cable to be installed is fixed by the cable fixing hole of the conformal cable holder and then welded. It is then installed into the cavity and finally welded to the exposed core wire of the RF cable to be installed by the connection plate of the microstrip substrate located in the substrate area. The microstrip substrate and the RF cable to be installed are directly welded, eliminating the need for connector accessories, reducing device size, simplifying the structure, and improving connection efficiency.

Description

Technical Field

[0001] This invention relates to the field of microwave component technology, and in particular to an interconnection structure and method for radio frequency cables in microwave components. Background Technology

[0002] Radio frequency (RF) cables are shielded cables used to transmit radio frequency microwave signals (i.e., electromagnetic energy). They are a structure used to interconnect functional units in various wireless communication systems, where radio frequency transmission is required between two or more circuit units in microwave components.

[0003] Therefore, in microwave components, long-span interconnections between RF link circuit units typically utilize RF cables. These RF cables usually need to be used in conjunction with connectors to form cable assemblies, which then connect the various functional units to create signal paths.

[0004] This type of cable assembly, consisting of a connector accessory and an RF cable, is too large to meet the current requirements for miniaturization and lightweighting of circuits, and its cost is also relatively high.

[0005] In existing technologies, RF cables are directly soldered to the RF lines of printed circuit boards. However, the RF cable and the printed circuit board are at a certain angle, resulting in a large parasitic effect at the solder joint, which cannot meet the RF frequency transmission characteristics.

[0006] To address the aforementioned issues, CN 112072435 B, "Method for Soldering RF Cables to Printed Circuit Boards for RF Strip Lines," discloses a connectorless method for direct soldering and interconnection with microstrip lines of microwave components. This method involves first creating slots in the printed circuit board to embed the metal shielding layer of the RF cable, then soldering the cable's metal shielding layer onto pads on the printed circuit board. These pads are equipped with metallized vias and indirectly connected to a reference ground to ensure the grounding requirements of the RF cable. Simultaneously, the cable core is parallel to the microstrip line and soldered together. This structure does indeed reduce parasitic effects to some extent. However, this structure is prone to electromagnetic crosstalk between circuit units in the RF link, requiring additional shielding design between circuits.

[0007] The above-mentioned welding method for product phase matching is difficult to disassemble quickly, making rework operations quite challenging. This structure is mainly suitable for single-channel connections to the outside world. When multiple channels are interconnected internally, this structure easily leads to poor signal isolation, inadequate shielding, and problems such as self-oscillation and electromagnetic crosstalk. Furthermore, directly welding the metal shielding layer of the RF cable to the ground layer of the circuit board requires high welding temperatures due to the large heat dissipation area and easy heat loss, making welding difficult. Therefore, it is detrimental to both product quality and large-scale use. Summary of the Invention

[0008] The purpose of this invention is to provide an interconnection structure and method for radio frequency cables in microwave components, which solves the electromagnetic crosstalk caused by signal leakage between radio frequency link circuit units without the need for additional shielding design.

[0009] To address the aforementioned technical problems, embodiments of the present invention provide an interconnection structure for radio frequency cables in microwave components, including a cavity and a conformal cable holder. The cavity includes a cable area disposed on its surface for placing the radio frequency cable to be installed and a substrate area for disposing of a microstrip substrate. The conformal cable holder includes a cable fixing hole in the front-to-back direction and a threaded hole in the top-to-bottom direction for connecting to the cavity. The cable fixing hole fixes the radio frequency cable to be installed and welds the metal shielding layer of the radio frequency cable to the conformal cable holder. The exposed core wire at one end of the radio frequency cable to be installed is welded to a corresponding connecting pad of the microstrip substrate disposed in the substrate area.

[0010] It also includes a transition structure and a recessed limiting groove disposed in the substrate area. The recessed limiting groove is used to limit the installation of the conformal cable seat. The transition structure matches the bottom shape of the conformal cable seat, so that the bottom of the conformal cable seat fits against the surface of the cavity.

[0011] It also includes an electroplated layer disposed on the conformal cable holder, the electroplated layer covering the entire outer surface of the conformal cable holder or disposed on the surface of the cable fixing hole.

[0012] The plating layer is either a gold plating layer or a silver plating layer.

[0013] The thickness of the coating is less than or equal to 0.5 μm.

[0014] This also includes a cable compartment located in the cable area and cable clips located in the cable compartment for securing the radio frequency cable to be installed.

[0015] The two ends of the radio frequency cable to be installed are fixed by the conformal cable holder.

[0016] The number of the base fixing holes is at least two, and the at least two base fixing holes are symmetrically distributed about the cable fixing holes.

[0017] In addition, embodiments of this application also provide a method for interconnecting radio frequency cables in microwave components, including:

[0018] S1. Fabricate a conformal cable holder corresponding to the radio frequency cable to be installed, and open a seat fixing hole, a solder groove and a cable mounting hole on the conformal cable holder.

[0019] S2, fabricate a cavity, and set a cable area for placing the radio frequency cable to be installed and a substrate area for setting the microstrip substrate on the surface of the cavity. On the substrate area adjacent to the cable area, a recessed limiting groove for installing and limiting the conformal cable seat is set, and a threaded hole matching the distance and diameter of the mounting hole of the conformal cable seat and a transition structure corresponding to the bottom surface of the conformal cable seat are opened on the recessed limiting groove so that the conformal cable seat fits the cavity surface.

[0020] S3, strip the two ends of the radio frequency cable to be installed to expose the core wire and the metal shielding layer, wherein the length of the exposed core wire is less than or equal to the length of the connecting plate of the microstrip substrate, and the length of the exposed metal shielding layer is greater than or equal to the depth of the cable fixing hole of the conformal cable seat.

[0021] S4, the stripped metal shielding layer of the radio frequency cable to be installed is passed through the cable fixing hole, and the metal shielding layer is welded to the cable fixing hole by the solder in the solder groove provided outside the cable fixing hole;

[0022] S5, after the conformal cable seat that has been welded is installed into the recessed limiting groove, it forms a closed circuit space together with the side wall of the cavity.

[0023] S6, the core wires at both ends of the radio frequency cable to be installed are soldered to the connecting plate of the microstrip substrate to achieve the final electrical interconnection between the cable and the circuit.

[0024] S2 further includes:

[0025] A gold plating layer is provided on the surface of at least one of the conformal cable seat, the recessed limiting groove, and the transition structure.

[0026] The interconnection structure and method for radio frequency cables in microwave components provided in this invention have the following advantages compared with the prior art:

[0027] The described interconnection structure and method for radio frequency cables in microwave components involves fixing the radio frequency cable to be installed in the cable fixing holes of a conformal cable holder, then welding it, and then installing it into the cavity. Finally, it is welded to the exposed core wire of the radio frequency cable to be installed via the connection pad of the microstrip substrate located in the substrate area. This direct welding of the microstrip substrate to the radio frequency cable eliminates the need for connector accessories, reduces device size, simplifies the structure, and improves connection efficiency. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A schematic diagram of one embodiment of the interconnection structure of a radio frequency cable in a microwave component provided in this invention;

[0030] Figure 2 A schematic front view of a cable mount in one embodiment of the interconnection structure of a radio frequency cable in a microwave component provided in this invention.

[0031] Figure 3 A top view of a cable mount in one embodiment of the interconnection structure of a radio frequency cable in a microwave component provided in this invention.

[0032] Figure 4 A schematic diagram of another embodiment of the interconnection structure of the radio frequency cable in the microwave component provided in the embodiments of the present invention;

[0033] Figure 5 A schematic flowchart illustrating the steps of an embodiment of the method for interconnecting radio frequency cables in microwave components provided by the present invention;

[0034] The components include: cavity-10, cable area-11, substrate area-12, RF cable to be installed-20, conformal cable holder-30, screw-31, cable fixing hole-32, solder groove-33, holder fixing hole-34, microstrip substrate-40, and connecting plate-41. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Please refer to Figure 1-5 , Figure 1 A schematic diagram of one embodiment of the interconnection structure of a radio frequency cable in a microwave component provided in this invention; Figure 2 A schematic front view of a cable mount in one embodiment of the interconnection structure of a radio frequency cable in a microwave component provided in this invention. Figure 3A top view of a cable mount in one embodiment of the interconnection structure of a radio frequency cable in a microwave component provided in this invention. Figure 4 A schematic diagram of another embodiment of the interconnection structure of the radio frequency cable in the microwave component provided in the embodiments of the present invention; Figure 5 This is a flowchart illustrating one embodiment of the method for interconnecting radio frequency cables in microwave components, provided by an embodiment of the present invention.

[0037] In one embodiment, the RF cable in the interconnection structure of the microwave component includes a cavity 10 and a conformal cable holder 30. The cavity 10 includes a cable area 11 disposed on its surface for placing the RF cable 20 to be installed and a substrate area 12 disposed on the microstrip substrate 40. The conformal cable holder 30 includes a cable fixing hole 32 in the front-to-back direction and a threaded hole 34 in the up-down direction for connecting with the cavity 10. The cable fixing hole 32 fixes the RF cable 20 to be installed and welds the metal shielding layer of the RF cable 20 to the conformal cable holder 30. The exposed core wire at one end of the RF cable 20 to be installed is welded to the corresponding connecting plate 41 of the microstrip substrate 40 disposed in the substrate area 12.

[0038] After fixing the radio frequency cable 20 to be installed in the cable fixing hole 32 of the conformal cable holder 30, it is welded and then installed into the cavity 10. Finally, it is welded to the exposed core wire of the radio frequency cable 20 and the connecting plate 41 of the microstrip substrate 40 located in the substrate area 12. The microstrip substrate 40 and the radio frequency cable 20 to be installed are directly welded, without the need for connector accessories, which reduces the device size, simplifies the structure, and improves the connection efficiency.

[0039] To further improve fixing efficiency and avoid slippage during installation that would reduce installation efficiency, in one embodiment, the interconnection structure of the radio frequency cable in the microwave component further includes a transition structure and a recessed limiting groove disposed in the substrate area 12. The recessed limiting groove is used to limit the installation of the conformal cable seat 30. The transition structure matches the bottom shape of the conformal cable seat 30, so that the bottom of the conformal cable seat 30 is in contact with the surface of the cavity 10.

[0040] The conformal cable holder 30 is positioned and limited by a recessed limiting groove, reducing the likelihood of slippage during installation and further improving installation efficiency and accuracy. A transition structure ensures that the bottom of the conformal cable holder 30 fits snugly against the surface of the cavity 10, forming a tight fit with the outer contours of both sides of the conformal cable holder 30. Together with the partition walls of the cavity 10, this ensures electromagnetic shielding within the most basic microwave component, improving the shielding effect.

[0041] This application does not limit the size of the sinking limiting groove or the shape of the transition structure. The depth of the sinking limiting groove is generally around 0.3 mm, and the transition structure is an arc structure. Those skilled in the art can make appropriate adjustments as needed.

[0042] To further improve the electromagnetic shielding effect, in one embodiment, the radio frequency cable in the interconnection structure of the microwave component also includes a plating layer disposed on the conformal cable base 30, the plating layer covering the entire outer surface of the conformal cable base 30 or disposed on the surface of the cable fixing hole 32.

[0043] This application does not limit the formation method, type, or thickness of the coating; the coating can be electroplated or chemically plated.

[0044] The shielding effect of the battery can be improved by setting the coating. Depending on the needs, partial electroplating or overall electroplating can be selected. This application does not limit this.

[0045] This application does not limit the material and thickness of the coating. The coating may be a gold electroplating layer, a silver electroplating layer, or other coatings, and the thickness of the coating may be less than or equal to 0.5 μm.

[0046] Since the cable will be placed in the cable area 11 after the core wire is welded in this application, if the core wire or conformal cable seat 30 is subjected to tension due to factors such as gravity, it will have a negative effect on the welding strength or effect. At best, it will reduce the electromagnetic shielding effect, and at worst, it will cause connection failure.

[0047] To address this technical problem, in one embodiment, the interconnection structure of the radio frequency cable in the microwave assembly further includes a cable compartment disposed in the cable area 11 and a cable clip disposed in the cable compartment for securing the radio frequency cable 20 to be installed.

[0048] The cable clips are used to fix and position the RF cable 20 to be installed, reducing the impact on the welding parts. At the same time, the position of the RF cable 20 to be installed is standardized, improving the installation efficiency.

[0049] This application does not impose any limitations on the structure, quantity, or fixing method of the cable clamps.

[0050] In this application, the conformal cable holder 30 is used to solder the radio frequency cable 20 to be installed. Generally, the two are soldered by setting a solder groove 33 in the cable fixing hole 32, and the conformal cable holder 30 is connected to the cavity 10 by setting a screw 31 in the threaded hole 34.

[0051] This application does not limit the size of the solder bath 33.

[0052] Preferably, both ends of the radio frequency cable to be installed are fixed by the conformal cable holder 30. Generally, multiple conformal cable holders 30 are arranged in parallel at equal intervals, but they can be freely arranged according to special needs.

[0053] This application does not limit the number, size, or spacing of the conformal cable bases 30.

[0054] This application does not limit the installation method of the conformal cable holder 30. In one embodiment, the number of the holder fixing holes 34 is at least two, and the at least two holder fixing holes 34 are symmetrically distributed about the cable fixing holes 32.

[0055] The mounting hole 34 in this application is generally a through hole, while a threaded hole is generally provided on the cavity.

[0056] This application does not limit the size and spacing of the mounting holes 34.

[0057] In addition, embodiments of this application also provide a method for interconnecting radio frequency cables in microwave components, including:

[0058] S1. Fabricate a conformal cable holder corresponding to the radio frequency cable to be installed, and open a seat fixing hole, a solder groove and a cable mounting hole on the conformal cable holder.

[0059] S2, fabricate a cavity, and set a cable area for placing the radio frequency cable to be installed and a substrate area for setting the microstrip substrate on the surface of the cavity. On the substrate area adjacent to the cable area, a recessed limiting groove for installing and limiting the conformal cable seat is set, and a threaded hole matching the distance and diameter of the mounting hole of the conformal cable seat and a transition structure corresponding to the bottom surface of the conformal cable seat are opened on the recessed limiting groove so that the conformal cable seat fits the cavity surface.

[0060] S3, strip the two ends of the radio frequency cable to be installed to expose the core wire and the metal shielding layer, wherein the length of the exposed core wire is less than or equal to the length of the connecting plate of the microstrip substrate, and the length of the exposed metal shielding layer is greater than or equal to the depth of the cable fixing hole of the conformal cable seat.

[0061] S4, the stripped metal shielding layer of the radio frequency cable to be installed is passed through the cable fixing hole, and the metal shielding layer is welded to the cable fixing hole by the solder in the solder groove provided outside the cable fixing hole;

[0062] S5. After the conformal cable seat with welding completed is installed into the recessed limiting groove, it forms a closed circuit space together with the side wall of the cavity. The installation here can be done by simply installing with screws, or by putting metal foil on the limiting groove and fixing it with the cable seat screws. Alternatively, metal foil can be attached between the top of the cable seat and the inner wall of the cavity to further enhance the shielding effect. The corresponding operation method can be adopted according to different needs and processes.

[0063] S6, the core wires at both ends of the radio frequency cable to be installed are soldered to the connecting plate of the microstrip substrate to achieve the final electrical interconnection between the cable and the circuit.

[0064] Since the interconnection method of the radio frequency cable in the microwave component is the same as the interconnection structure of the radio frequency cable in the microwave component described above, and has the same beneficial effects, this application will not elaborate on it.

[0065] To further improve the electromagnetic shielding effect, in one embodiment, S2 further includes:

[0066] A gold plating layer is provided on the surface of at least one of the conformal cable seat, the recessed limiting groove, and the transition structure.

[0067] It should be noted that the gold plating layer of the conformal cable holder in this application can be set locally or as a whole, and can be set accordingly as needed.

[0068] This application does not limit the material and thickness of the electroplated layer. The electroplated layer is a gold electroplated layer or other electroplated layer, and the thickness of the electroplated layer is less than or equal to 0.5 μm.

[0069] This application does not limit the size or shape of the various components.

[0070] Compared with the prior art, the embodiments of this application, by fabricating a conformal cable base, welding it to both ends of the radio frequency cable, and then fixing it to the cavity with screws, form a complete and continuous metal partition structure within the cavity through the conformal cable base, achieving the following beneficial effects:

[0071] 1) Because it is installed using the cavity's own structure, there are no additional connector accessories, which takes up little product space and is conducive to miniaturized applications;

[0072] 2) It adopts a conformal structure design similar to a cavity partition wall, which can achieve high isolation requirements between channels, avoid electromagnetic crosstalk caused by signal leakage, and eliminate the need for additional electromagnetic shielding design in the product.

[0073] 3) The conformal structure design using screw-in assembly allows for quick cable disassembly;

[0074] 4) Except for the welding of the radio frequency cable, the rest of the installation is simple. The product does not need to be heated as a whole, which avoids unnecessary thermal stress and is conducive to the overall reliability of the product.

[0075] 5) The cost of the RF cable assembly is reduced due to the absence of connector accessories.

[0076] In summary, the interconnection structure and method for the radio frequency cable in microwave components provided in this application embodiment fixes the radio frequency cable to be installed in the cable fixing hole of the conformal cable holder and then welds it, then installs it into the cavity, and finally welds the exposed core wire of the radio frequency cable to be installed to the connection plate of the microstrip substrate located in the substrate area. The microstrip substrate and the radio frequency cable to be installed are directly welded, eliminating the need for connector accessories, reducing device size, simplifying the structure, and improving connection efficiency.

[0077] The interconnection structure and method of the radio frequency cable in microwave components provided by this invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make several improvements and modifications to this invention without departing from the principles of this invention, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. An interconnection structure for radio frequency cables in microwave components, characterized in that, The device includes a cavity and a conformal cable holder. The cavity includes a cable area on its surface for placing the end of a radio frequency cable to be installed and a substrate area for mounting a microstrip substrate. The conformal cable holder includes a cable fixing hole in the front-to-back direction and a seat fixing hole in the top-to-bottom direction for connecting with the cavity. The cable fixing hole fixes the radio frequency cable to be installed and welds the metal shielding layer of the radio frequency cable to be installed to the conformal cable holder. The exposed core wire at one end of the radio frequency cable to be installed is welded to the corresponding connecting pad of the microstrip substrate in the substrate area. It also includes a transition structure and a recessed limiting groove disposed in the substrate area. The recessed limiting groove is used to limit the installation of the conformal cable seat. The transition structure matches the bottom shape of the conformal cable seat, so that the bottom of the conformal cable seat fits against the surface of the cavity. It also includes a plating layer disposed on the conformal cable holder, the plating layer covering the entire outer surface of the conformal cable holder or disposed on the surface of the cable fixing hole.

2. The interconnection structure of the radio frequency cable in a microwave component as described in claim 1, characterized in that, The plating layer is a gold electroplating layer or a silver electroplating layer.

3. The interconnection structure of the radio frequency cable in a microwave component as described in claim 2, characterized in that, The thickness of the coating is less than or equal to 0.5 μm.

4. The interconnection structure of the radio frequency cable in a microwave component as described in claim 3, characterized in that, It also includes a cable compartment located in the cable area and cable clips located in the cable compartment for securing the radio frequency cable to be installed.

5. The interconnection structure of the radio frequency cable in a microwave component as described in claim 4, characterized in that, The two ends of the radio frequency cable to be installed are fixed by the conformal cable holder.

6. The interconnection structure of the radio frequency cable in a microwave assembly as described in claim 5, characterized in that, The number of the base fixing holes is at least two, and the at least two base fixing holes are symmetrically distributed about the cable fixing holes.

7. A method for interconnecting radio frequency cables in microwave components, characterized in that, include: S1, Fabricate a conformal cable holder corresponding to the RF cable to be installed, and open a seat fixing hole, a solder groove and a cable mounting hole on the conformal cable holder; S2, fabricate a cavity, and set a cable area for placing the radio frequency cable to be installed and a substrate area for setting the microstrip substrate on the surface of the cavity. On the substrate area adjacent to the cable area, a recessed limiting groove for installing and limiting the conformal cable seat is set, and a threaded hole matching the distance and diameter of the mounting hole of the conformal cable seat and a transition structure corresponding to the bottom surface of the conformal cable seat are opened on the recessed limiting groove so that the conformal cable seat fits the cavity surface. S3, strip the two ends of the radio frequency cable to be installed to expose the core wire and the metal shielding layer, wherein the length of the exposed core wire is less than or equal to the length of the connecting plate of the microstrip substrate, and the length of the exposed metal shielding layer is greater than or equal to the depth of the cable fixing hole of the conformal cable seat. S4, the stripped metal shielding layer of the radio frequency cable to be installed is passed through the cable fixing hole, and the metal shielding layer is welded to the cable fixing hole by the solder in the solder groove provided on the outside of the cable fixing hole; S5, after the conformal cable seat that has been welded is installed into the recessed limiting groove, it forms a closed circuit space together with the side wall of the cavity. S6, the core wires at both ends of the radio frequency cable to be installed are soldered to the connecting plate of the microstrip substrate to achieve the final electrical interconnection between the cable and the circuit.

8. The method for interconnecting radio frequency cables in microwave components as described in claim 7, characterized in that, S2 further includes: A gold plating layer is provided on the surface of at least one of the conformal cable seat, the recessed limiting groove, and the transition structure.

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