A multilayer structure of a low-temperature superconducting wire film composite electromagnetic shield FPC

Abstract

The present application relates to the technical fields of low-temperature signal transmission and flexible circuit board, and specifically discloses a kind of low-temperature superconducting wire film composite electromagnetic shielding FPC multilayer structure, including superconducting wire layer, respectively being arranged in the thickness direction two sides of superconducting wire layer flexible insulating layer, and at least one side flexible insulating layer is set to the surface of superconducting wire layer surface superconducting film shielding layer back to superconducting wire layer;Superconducting wire layer and superconducting film shielding layer are separated by flexible insulating layer and are stacked in the thickness direction, and the width of superconducting film shielding layer is greater than the width of the shielded area in superconducting wire layer to form overhanging area.The present application stacks superconducting wire layer and superconducting film shielding layer in the same flexible circuit board, forms planar magnetic flux discharge path near the wire using the complete diamagnetism of superconducting material, eliminates the space and support structure required by external shielding, gives the overall bending ability and realizes shielding effect on-demand adjustment, suitable for low-temperature mobile platform and narrow space scene.

Description

Technical Field

[0001] This invention relates to the field of low-temperature signal transmission and flexible circuit board technology, specifically to a multilayer structure of a superconducting wire film composite electromagnetic shielding FPC for low-temperature applications. Background Technology

[0002] With the rapid development of cryogenic technologies such as quantum computing and low-temperature precision measurement, the stable transmission of high-sensitivity signals in cryogenic environments has become one of the key bottleneck issues. In cryogenic systems, signal transmission cables not only need to meet the electrical performance requirements at extremely low temperatures, but also need to have good electromagnetic shielding capabilities to prevent external electromagnetic interference from affecting weak signals.

[0003] Currently, cryogenic systems mainly use traditional coaxial cables in conjunction with macroscopic shielding chambers, shielding cylinders, or independent metal shielding covers and shielding boxes to achieve signal transmission and electromagnetic protection.

[0004] However, existing solutions design and install the signal transmission line and the shielding structure as independent components. The shielding structure requires additional installation space and rigid structural support, resulting in a large system size, increased weight, and inflexibility, making it difficult to adapt to cryogenic dynamic platforms, confined spaces, or systems with limited mass. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-layer structure of superconducting wire film composite electromagnetic shielding FPC for low temperature applications, in order to solve the transmission problem of signal cables in low-temperature dynamic platforms, confined spaces, or environments with limited mass.

[0006] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution:

[0007] A multilayer structure of superconducting wire film composite electromagnetic shielding FPC for low-temperature applications includes:

[0008] Superconducting wire layer, used to transmit cryogenic electrical signals;

[0009] Flexible insulating layers are respectively disposed on both sides of the superconducting conductor layer in the thickness direction to provide flexible support and electrical insulation;

[0010] A superconducting thin film shielding layer is disposed on at least one side of the flexible insulating layer facing away from the superconducting conductive layer and located at the outermost edge of the flexible circuit board;

[0011] The superconducting conductor layer and the superconducting thin film shielding layer are insulated from each other by the flexible insulating layer, and are stacked in the thickness direction of the flexible circuit board to form an integrated electromagnetic shielding structure that combines a linear conductor and a planar thin film.

[0012] Furthermore, the superconducting thin film shielding layer is only disposed on the surface of the flexible insulating layer facing away from the superconducting wire layer on one side of the thickness direction of the superconducting wire layer, forming a one-sided shielding structure.

[0013] Furthermore, the superconducting thin film shielding layer is simultaneously disposed on the surfaces of the flexible insulating layers facing away from the superconducting wire layer on both sides of the thickness direction of the superconducting wire layer, forming a double-sided sandwich shielding structure that sandwiches the superconducting wire layer in the middle.

[0014] Furthermore, the dimension of the superconducting thin film shielding layer in the width direction of the superconducting wire layer is greater than the width of the shielded area in the superconducting wire layer, so that the side of the superconducting thin film shielding layer extends outward relative to the edge of the outermost wire in the superconducting wire layer, forming an extended area for suppressing edge magnetic field diffraction and leakage.

[0015] Furthermore, the extended region extends outward on one or both sides along the width direction of the superconducting conductor layer.

[0016] Furthermore, the vertical distance between the superconducting wire layer and the superconducting thin film shielding layer is limited by the thickness of the flexible insulating layer, and the value of the vertical distance ranges from the micrometer level to the hundred-micrometer level.

[0017] Furthermore, the flexible insulating layer is made of any one of insulating materials such as polyimide, polyester, liquid crystal polymer, or flexible polytetrafluoroethylene.

[0018] Furthermore, the superconducting wire layer is a single-layer structure or a multi-layer structure.

[0019] A design method for a low-temperature superconducting wire film composite electromagnetic shielding flexible circuit board includes the following steps:

[0020] Step 1: Determine the operating temperature, external electromagnetic field strength, allowable mass, allowable thickness, bending radius, and target shielding area of ​​the cryogenic system;

[0021] Step 2: Determine the number of superconducting conductors, line width, line spacing, and routing pattern of the superconducting conductor layer based on the parameters from Step 1;

[0022] Step 3: Set the vertical distance between the superconducting thin film shielding layer and the superconducting wire layer according to the target shielding effect, and set the outward extension length of the superconducting thin film shielding layer relative to the superconducting wire layer;

[0023] Step 4: Evaluate the magnetic flux density, inter-line leakage field, and edge leakage field in the critical circuit region through electromagnetic simulation or experimentation;

[0024] Step 5: If the shielding effect is insufficient, the shielding effect can be improved by reducing the vertical distance, increasing the outward extension length, or changing to a double-sided sandwich shielding structure.

[0025] Step 6: Verify the critical current, critical magnetic field, and low-temperature mechanical reliability of the superconducting material to form an FPC structure that meets the target shielding requirements.

[0026] Furthermore, the target shielding effect in step three is quantified as the maximum allowable magnetic flux density or minimum shielding effectiveness value in the area where the conductor layer is located; the vertical distance and the extension length are adjusted according to the correspondence between the target shielding effect and the electromagnetic simulation or test results.

[0027] Compared with the prior art, this application has the following advantages:

[0028] This invention integrates a superconducting wire layer, a flexible insulating layer, and a superconducting thin film shielding layer within the same flexible circuit board, so that the shielded wire and the shielding film are separated by only a micron-level insulating layer. By utilizing the complete diamagnetism of the superconducting material, a planar magnetic flux discharge path is formed near the wire, which shortens the shielding path and eliminates the space and support structure required for external shielding components, reducing the system mass and volume, while giving the whole system bending capability to adapt to moving platforms and confined spaces. Attached Figure Description

[0029] To more clearly illustrate the embodiments of the present invention or the technical solutions in 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 merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of a single-sided shielding structure according to an embodiment of the present invention.

[0031] Figure 2 This is a schematic diagram of the double-sided sandwich shielding structure according to an embodiment of the present invention.

[0032] The labels in the diagram represent the following:

[0033] 1. Superconducting thin film shielding layer; 2. Flexible insulating layer; 3. Superconducting wire layer. Detailed Implementation

[0034] 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.

[0035] like Figure 1 and Figure 2 As shown, the low-temperature superconducting wire and film composite electromagnetic shielding FPC multilayer structure of the present invention includes a flexible insulating layer 2, a superconducting wire layer 3, and a superconducting thin film shielding layer 1.

[0036] Specifically, flexible insulating layers 2 are respectively disposed on both sides of the superconducting conductive layer 3 in the thickness direction, serving to provide flexible support and electrical insulation. The superconducting conductive layer 3 is disposed between the flexible insulating layers 2 for transmitting electrical signals in the cryogenic precision system. A superconducting thin-film shielding layer 1 is disposed on at least one side of the flexible insulating layer 2 facing away from the superconducting conductive layer 3, and is located at the outermost edge of the flexible circuit board.

[0037] The superconducting conductor layer 3 and the superconducting thin film shielding layer 1 are insulated from each other by a flexible insulating layer 2 and are stacked in the thickness direction of the flexible circuit board to form an integrated electromagnetic shielding structure that combines a linear conductor and a planar thin film.

[0038] Thus, the superconducting conductor layer 3 and the superconducting thin film shielding layer 1 together form a composite electromagnetic shielding structure that combines a linear conductor and a planar thin film. This allows the shielded conductor and the shielding film to be separated by only one insulating layer, shortening the shielding path and eliminating the space and support structure required for external shielding components, reducing the system's mass and volume, while also giving the whole system bending capability to adapt to moving platforms and confined spaces.

[0039] The flexible insulating layer 2 is made of polyimide (PI), but can also be made of polyester, liquid crystal polymer (LCP), polytetrafluoroethylene (PTFE) based flexible materials, or other low-temperature compatible flexible insulating materials. The flexible insulating layer 2 provides flexible support and electrical insulation, while its thickness defines the vertical distance between the superconducting conductor layer 3 and the superconducting thin film shielding layer 1.

[0040] The vertical distance ranges from micrometers to hundreds of micrometers. When space permits and the shielding effect needs to be improved, this distance should be reduced first.

[0041] The superconducting wire layer 3 and the superconducting thin film shielding layer 1 are made of any one of niobium (Nb), lead (Pb), niobium titanium (NbTi), niobium tritin (Nb3Sn) or other superconducting materials, as long as the superconducting materials are in the superconducting state in the actual application scenario.

[0042] Material selection should ensure that the device is in a fully superconducting state at the predetermined operating temperature and magnetic field. In actual design, the material and thickness can be determined based on the critical temperature, critical magnetic field, critical current density, fabrication process, and FPC bending requirements.

[0043] Specifically, the superconducting conductor layer 3 can be a single-layer structure or a multi-layer structure, and the conductors therein can be arranged in parallel, cross, or serpentine patterns, or the wiring structure can be designed to be shielded as needed.

[0044] Adhesive layers are applied between the flexible insulating layer 2 and the superconducting wire layer 3, and between the flexible insulating layer 2 and the superconducting thin film shielding layer 1, respectively. These layers are then laminated and cured to ensure a tight bond. The adhesive used is any one of low-temperature epoxy resin, polyimide adhesive, or acrylic adhesive, maintaining its bonding strength at low temperatures.

[0045] Example 1

[0046] like Figure 1 As shown, in one embodiment, the superconducting thin-film shielding layer 1 is disposed only on the surface of the flexible insulating layer 2 facing away from the superconducting wire layer 3 on one side of the thickness direction of the superconducting wire layer 3, forming a one-sided shielding structure. The superconducting thin-film shielding layer 1 is disposed below or above the superconducting wire layer 3 for providing one-sided shielding for the wire layer.

[0047] This structure is suitable for applications where the external interference magnetic field mainly comes from one direction or where the system has strict limitations on thickness and mass. It achieves basic shielding while controlling the overall thickness and material usage of the FPC.

[0048] Among them, the superconducting thin film shielding layer 1 can cover only the critical circuit area or cover multiple critical circuit areas in sections, thereby controlling the amount of material used, the structural width and the heat load while meeting the shielding requirements.

[0049] Example 2

[0050] like Figure 2 As shown, in another embodiment, the superconducting thin film shielding layer 1 is simultaneously disposed on the surfaces of the flexible insulating layers 2 facing away from the superconducting wire layer 3 on both sides of the thickness direction of the superconducting wire layer 3, forming a double-sided sandwich shielding structure that sandwiches the superconducting wire layer 3 in the middle. That is, the superconducting thin film shielding layer 1 is disposed above and below the superconducting wire layer 3.

[0051] The double-sided sandwich shielding structure can reduce the influence of external magnetic fields on the conductor layer and improve the shielding symmetry of the conductor layer in the vertical direction.

[0052] When the external electromagnetic field of the cryogenic system is strong or the signal integrity requirements are high, a double-sided sandwich shielding structure is preferred to improve the shielding effect.

[0053] Example 3

[0054] The dimension of the superconducting thin film shielding layer 1 in the width direction of the superconducting wire layer 3 is greater than the width of the shielded area in the superconducting wire layer 3, so that the side of the superconducting thin film shielding layer 1 extends outward relative to the edge of the outermost wire in the superconducting wire layer 3, forming an extended area for suppressing edge magnetic field diffraction and leakage.

[0055] The extended region extends outward on one or both sides along the width direction of the superconducting conductor layer 3. Within a reasonable range, the larger the extended region, the stronger the ability to suppress edge leakage field, but it will increase the width of the FPC and the amount of material used.

[0056] Based on shielding parameters and spatial constraints, the single- or double-sided extension length of the superconducting thin film relative to the superconducting conductor layer can be adjusted to obtain different shielding effects.

[0057] The extended region of the superconducting thin film can be designed as rectangular, stepped, rounded, or locally widened to accommodate the FPC installation space and edge leakage field distribution.

[0058] Example 4

[0059] This invention also includes a design method for the aforementioned superconducting wire film composite electromagnetic shielding FPC, specifically comprising the following steps:

[0060] Step 1: Determine the operating temperature, external electromagnetic field strength, allowable mass, allowable thickness, bending radius, and target shielding area of ​​the cryogenic system.

[0061] Step 2: Determine the number of conductors, line width, line spacing, and routing pattern of the superconducting conductor layer 3 based on the parameters from Step 1.

[0062] Step 3: Set the vertical distance between the superconducting thin-film shielding layer 1 and the superconducting conductive layer 3 according to the target shielding effect, and set the overhang length of the superconducting thin-film shielding layer 1 relative to the superconducting conductive layer 3. The target shielding effect is quantified as the maximum allowable magnetic flux density or minimum shielding effectiveness value in the region where the conductive layer is located. The vertical distance and overhang length are adjusted according to the correspondence between the target shielding effect and the results of electromagnetic simulation or experiment. By adjusting the vertical distance between the wire and film, the overhang length of the superconducting thin film, and the single-sided or double-sided thin-film structure, the shielding effect can be adjusted for different circuit regions, different external field intensities, and different spatial constraints.

[0063] Step 4: Evaluate the magnetic flux density, inter-line leakage field, and edge leakage field in critical circuit regions through electromagnetic simulation or experiments. Design verification can be achieved using EJ constitutive relation electromagnetic simulation, low permeability approximate simulation, experimental calibration, or a combination of methods for cross-verification.

[0064] Step 5: If the shielding effect is insufficient, the shielding effect can be improved by reducing the vertical distance, increasing the outward extension length, or changing to a double-sided sandwich shielding structure.

[0065] Step 6: Verify the critical current, critical magnetic field, and low-temperature mechanical reliability of the superconducting material to form an FPC structure that meets the target shielding requirements.

[0066] Using the above design method, the FPC structural parameters can be flexibly adjusted according to different cryogenic system operating conditions and shielding requirements, so as to achieve the matching and optimization of shielding effect and system constraints.

[0067] Example 5

[0068] Based on the above embodiments, the present invention also provides the following optional alternatives:

[0069] The flexible insulation layer 2 can be made of polyimide, or it can be made of polyester, liquid crystal polymer, polytetrafluoroethylene flexible material or other low-temperature compatible flexible insulation material.

[0070] The superconducting conductor layer 3 can be a single layer, multiple layers, parallel arrangement, cross arrangement, serpentine arrangement, or any routing structure formed according to the actual circuit function. The superconducting thin film shielding layer can be placed below, above, or on both sides of the conductor layer; it can also cover only the critical circuit area or cover multiple critical circuit areas in sections. The superconducting material can be replaced with niobium, lead, niobium-titanium, niobium-tin, high-temperature superconducting materials, or other materials that can enter the superconducting state at low temperatures, depending on the operating temperature range.

[0071] The extended region of the superconducting thin film can be designed as rectangular, stepped, rounded, or locally widened to accommodate the FPC installation space and edge leakage field distribution.

[0072] Design verification can be performed using EJ constitutive relation electromagnetic simulation, low permeability approximate simulation, experimental calibration, or a combination of methods for cross-verification.

[0073] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered as falling within the scope of protection of the embodiments of the present invention.

Claims

1. A multilayer structure of superconducting wire film composite electromagnetic shielding FPC for low-temperature applications, characterized in that, include: Superconducting wire layer (3) is used to transmit cryogenic electrical signals; Flexible insulating layers (2) are respectively disposed on both sides of the superconducting conductor layer (3) in the thickness direction to provide flexible support and electrical insulation; A superconducting thin film shielding layer (1) is disposed on the surface of the flexible insulating layer (2) on at least one side facing away from the superconducting wire layer (3) and located at the outermost edge of the flexible circuit board; The superconducting conductor layer (3) and the superconducting thin film shielding layer (1) are insulated from each other by the flexible insulating layer (2) and are stacked in the thickness direction of the flexible circuit board to form an integrated electromagnetic shielding structure of linear conductor and planar thin film composite.

2. The multilayer structure of a low-temperature superconducting wire film composite electromagnetic shielding FPC according to claim 1, characterized in that, The superconducting thin film shielding layer (1) is only disposed on the surface of the flexible insulating layer (2) facing away from the superconducting wire layer (3) on one side of the thickness direction of the superconducting wire layer (3), forming a one-sided shielding structure.

3. The multilayer structure of a low-temperature superconducting wire film composite electromagnetic shielding FPC according to claim 1, characterized in that, The superconducting thin film shielding layer (1) is simultaneously disposed on the surface of the flexible insulating layer (2) facing away from the superconducting wire layer (3) on both sides of the thickness direction of the superconducting wire layer (3), forming a double-sided sandwich shielding structure that sandwiches the superconducting wire layer (3) in the middle.

4. A multilayer structure of superconducting wire film composite electromagnetic shielding FPC for low temperature applications according to any one of claims 1 to 3, characterized in that, The dimension of the superconducting thin film shielding layer (1) in the width direction of the superconducting wire layer (3) is greater than the width of the shielded area in the superconducting wire layer (3), so that the side of the superconducting thin film shielding layer (1) extends outward relative to the edge of the outermost wire in the superconducting wire layer (3), forming an extended area for suppressing edge magnetic field diffraction and leakage.

5. The multilayer structure of a low-temperature superconducting wire film composite electromagnetic shielding FPC according to claim 4, characterized in that, The extended region extends outward on one or both sides along the width direction of the superconducting conductor layer (3).

6. A multilayer structure of superconducting wire film composite electromagnetic shielding FPC for low temperature applications according to any one of claims 1 to 3, characterized in that, The vertical distance between the superconducting wire layer (3) and the superconducting thin film shielding layer (1) is limited by the thickness of the flexible insulating layer (2), and the value of the vertical distance ranges from micrometers to hundreds of micrometers.

7. A multilayer structure of superconducting wire film composite electromagnetic shielding FPC for low temperature applications according to any one of claims 1 to 3, characterized in that, The flexible insulating layer (2) is made of any one of the insulating materials such as polyimide, polyester, liquid crystal polymer or polytetrafluoroethylene flexible.

8. A multilayer structure of superconducting wire film composite electromagnetic shielding FPC for low temperature applications according to any one of claims 1 to 3, characterized in that, The superconducting wire layer (3) is a single-layer structure or a multi-layer structure.

9. A design method for a low-temperature superconducting wire film composite electromagnetic shielding flexible circuit board as described in claim 1, characterized in that, Includes the following steps: Step 1: Determine the operating temperature, external electromagnetic field strength, allowable mass, allowable thickness, bending radius, and target shielding area of ​​the cryogenic system; Step 2: Determine the number of conductors, line width, line spacing and routing of the superconducting conductor layer (3) based on the parameters in Step 1; Step 3: Set the vertical distance between the superconducting thin film shielding layer (1) and the superconducting wire layer (3) according to the target shielding effect, and set the extension length of the superconducting thin film shielding layer (1) relative to the superconducting wire layer (3); Step 4: Evaluate the magnetic flux density, inter-line leakage field, and edge leakage field in the critical circuit region through electromagnetic simulation or experimentation; Step 5: If the shielding effect is insufficient, the shielding effect can be improved by reducing the vertical distance, increasing the outward extension length, or changing to a double-sided sandwich shielding structure. Step 6: Verify the critical current, critical magnetic field, and low-temperature mechanical reliability of the superconducting material to form an FPC structure that meets the target shielding requirements.

10. The design method of a low-temperature superconducting wire film composite electromagnetic shielding flexible circuit board according to claim 9, characterized in that, In step three, the target shielding effect is quantified as the maximum allowable magnetic flux density or minimum shielding effectiveness value in the area where the conductor layer is located; the vertical distance and the extension length are adjusted according to the correspondence between the target shielding effect and the electromagnetic simulation or test results.

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