Transmission line and preparation method thereof
By using a resin layer with a low dielectric constant and a porous structure in the dielectric layer of the transmission line, combined with the first and second bonding layers, the problems of the traditional transmission line's small line width, high manufacturing difficulty, and low power are solved, and a larger line width, higher power withstand and better flexibility are achieved.
Patent Information
- Application Number
- CN202311814859.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-26
- Publication Date
- 2025-06-27
AI Technical Summary
When a traditional transmission line meets the demand of an impedance of about 50 ohms, the dielectric constant of the dielectric layer is greater than 2, resulting in a decrease in line width, increasing manufacturing difficulty, reducing power, and increasing dielectric layer thickness leads to an increase in weight and reducing flexibility.
By using a resin layer with a dielectric constant less than or equal to 3 in the dielectric layer of the transmission line, and a plurality of pore structures are provided in the resin layer, accounting for ≥90%, to reduce the dielectric constant of the dielectric layer to ≤2, and at the same time, the first and second bonding layers are used to define a dielectric constant less than or equal to 4.
It is realized that without reducing the transmission line width, the power of the transmission line is increased, which is convenient for manufacturing, and the self-weight and mass surface density of the transmission line is reduced, flexibility is increased, and flexibility is improved and the use space is improved.
Smart Images
Figure CN120221964A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of electronic communication technologies, and particularly to a transmission line and a preparation method thereof. Background Art
[0002] Transmission lines include microstrip lines, strip lines, coplanar waveguide lines, etc., which play a role in transmitting signals in radio frequency circuits. Usually, the impedance of a transmission line is about 50 ohms, and it is an important component in radio frequency circuits.
[0003] Generally, when designing a transmission line, the dielectric constant and thickness of the dielectric layer in the transmission line will affect the line width of the transmission line. However, the dielectric constant of the dielectric layer in the transmission line is usually > 2. In order to meet the requirement that the impedance of the transmission line is about 50 ohms, without increasing the thickness of the dielectric layer, only the line width of the transmission line can be reduced. Moreover, the larger the dielectric constant, the smaller the line width of the transmission line. This not only increases the manufacturing difficulty of the transmission line but also reduces the power tolerance of the transmission line. Therefore, in traditional technologies, the thickness of the dielectric layer is usually increased to meet the requirement that the impedance of the transmission line is about 50 ohms, which can not only increase the line width of the transmission line but also facilitate manufacturing and improve its power tolerance. However, the increase in the thickness of the dielectric layer increases the weight of the transmission line and reduces the flexibility of the transmission line, resulting in a decrease in the flexibility of the transmission line, making it difficult to conform to the substrate, and increasing the usage space. Summary of the Invention
[0004] Based on this, in view of the above problems, it is necessary to provide a transmission line and a preparation method thereof. In the transmission line of the present invention, the dielectric constant of the dielectric layer ≤ 2, which can not only maintain the line width of the transmission line, improve the power tolerance of the transmission line, facilitate manufacturing, but also reduce the self-weight of the transmission line and increase the flexibility.
[0005] A transmission line includes a transmission line layer, a grounding layer, and a dielectric layer sandwiched between the transmission line layer and the grounding layer. Among them, the dielectric layer includes a resin layer with a plurality of pore structures, a first adhesive layer, and a second adhesive layer. The first adhesive layer is sandwiched between the resin layer and the transmission line layer, and the second adhesive layer is sandwiched between the resin layer and the grounding layer; and the dielectric layer also simultaneously satisfies the following conditions:
[0006] (1) The dielectric constants of the first adhesive layer and the second adhesive layer are both less than or equal to 4;
[0007] (2) The dielectric constant of the resin used in the resin layer is less than or equal to 3;
[0008] (3) The volume ratio of the pore structures in the resin layer ≥ 90%.
[0009] In one embodiment, the pore structure is an air hole, and the air holes are distributed in the resin layer;
[0010] Alternatively, the hole structure is an air column that penetrates through the resin layer, and both ends of the air column are respectively sealed by the first adhesive layer and the second adhesive layer.
[0011] In one embodiment, the resin is selected from at least one of polydimethylsiloxane, polytetrafluoroethylene, polyetheretherketone, liquid crystal polymer, or polyimide.
[0012] In one embodiment, the first adhesive layer and the second adhesive layer are each independently selected from at least one of a silicone adhesive layer, an epoxy adhesive layer, or an acrylic adhesive layer.
[0013] In one embodiment, the thickness of the dielectric layer is 0.04 mm - 1.1 mm.
[0014] In one embodiment, the thickness of the resin layer is 0.025 mm - 0.99 mm;
[0015] And / or, the thicknesses of the first adhesive layer and the second adhesive layer are each independently selected from 0.01 mm - 0.025 mm.
[0016] In one embodiment, the line width of the transmission line is 0.1 mm - 5 mm.
[0017] A method for manufacturing a transmission line as described above, comprising the following steps:
[0018] Prepare a resin layer having a plurality of hole structures;
[0019] Use a flexible copper clad laminate to prepare a transmission line layer and a ground layer, and prepare a first semi-cured layer on the flexible film surface of the transmission line layer and a second semi-cured layer on the flexible film surface of the ground layer;
[0020] Bond the two surfaces of the resin layer to the first semi-cured layer and the second semi-cured layer respectively, and obtain a transmission line after curing.
[0021] In one embodiment, the step of preparing a resin layer having a plurality of hole structures includes:
[0022] Form a mixture of resin and pore-forming particles and cure it, then dissolve the pore-forming particles to form air holes, and obtain a resin layer having a plurality of air holes, wherein the volume ratio of the pore-forming particles in the mixture is ≥ 90%;
[0023] Alternatively, place the resin on a molding substrate and cure it, and demold to obtain a resin layer having a plurality of air columns, wherein the molding substrate has a plurality of vertically distributed rods, and the total projected area of the rods on the molding substrate accounts for ≥ 90% of the area of the molding substrate.
[0024] In one embodiment, the curing temperature is 60°C - 250°C and the time is 4h - 24h.
[0025] In the dielectric layer of the present invention, by selecting a resin with a dielectric constant less than or equal to 3 to prepare a resin layer and regulating the volume ratio of the pore structure in the resin layer to be ≥90%, the dielectric constant of the resin layer can be reduced. At the same time, by sandwiching the resin layer between the first adhesive layer and the second adhesive layer and defining the dielectric constants of the first adhesive layer and the second adhesive layer to be less than or equal to 4, the dielectric constant of the dielectric layer is ≤2. Thus, in order to meet the requirement that the impedance of the transmission line is about 50 ohms, the present invention does not need to reduce the line width of the transmission line, which can not only reduce the loss of the transmission line, improve the power bearing capacity of the transmission line, but also facilitate manufacturing. At the same time, the present invention does not need to increase the thickness of the dielectric layer 2, and can reduce the density of the dielectric layer 2 to 1.3 g / cm 3 Thereafter, the areal mass density of the transmission line can be further reduced, such that the areal mass density of the transmission line is ≤50 g / m 2 , so that the self-weight of the transmission line can be reduced, and the flexibility of the transmission line can be increased, making the transmission line more flexible and easier to conform to the substrate, saving the use space. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 It is a schematic structural diagram of a transmission line according to an embodiment of the present invention;
[0027] Figure 2 It is a schematic structural diagram of a transmission line according to another embodiment of the present invention.
[0028] In the figure: 1, transmission line layer; 2, dielectric layer; 3, grounding layer; 21, first adhesive layer; 22, resin layer; 23, second adhesive layer. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0029] To facilitate the understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, these embodiments or examples are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.
[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention herein are for the purpose of describing specific embodiments or examples only, and are not intended to limit the present invention. The optional range of the term "and / or" used herein includes any one of two or more related listed items, and also includes any and all combinations of the related listed items. The any and all combinations include any two related listed items, any more related listed items, or the combination of all related listed items.
[0031] Combined with Figure 1 and Figure 2 As shown, the transmission line of the present invention includes: a transmission line layer 1, a grounding layer 3, and a dielectric layer 2 sandwiched between the transmission line layer 1 and the grounding layer 3. Among them, the dielectric layer 2 includes a resin layer 22 having a plurality of pore structures, a first adhesive layer 21, and a second adhesive layer 23. The first adhesive layer 21 is sandwiched between the resin layer 22 and the transmission line layer 1, and the second adhesive layer 23 is sandwiched between the resin layer 22 and the grounding layer 3.
[0032] Specifically, the dielectric layer 2 also simultaneously satisfies the following conditions:
[0033] (1) The dielectric constants of the first adhesive layer 21 and the second adhesive layer 23 are both less than or equal to 4;
[0034] (2) The resin used for the resin layer 22 has a dielectric constant less than or equal to 3;
[0035] (3) The volume ratio of the pore structure in the resin layer 22 is ≥90%.
[0036] In the dielectric layer 2 of the present invention, by selecting a resin with a dielectric constant less than or equal to 3 to prepare the resin layer 22 and regulating the volume ratio of the pore structure in the resin layer 22 to be ≥90%, the dielectric constant of the resin layer 22 can be reduced. At the same time, by sandwiching the resin layer 22 between the first adhesive layer 21 and the second adhesive layer 23 and defining the dielectric constants of the first adhesive layer 21 and the second adhesive layer 23 to be less than or equal to 4, the dielectric constant of the dielectric layer 2 is ≤2.
[0037] Thus, in order to meet the requirement that the impedance of the transmission line is about 50 ohms, the present invention does not need to reduce the line width of the transmission line, which can not only improve the power handling capacity of the transmission line, but also facilitate manufacturing; at the same time, the present invention does not need to increase the thickness of the dielectric layer 2, and can reduce the density of the dielectric layer 2 to 1.3 g / cm 3 Thereafter, the areal density of the transmission line can be further reduced, so that the areal density of the transmission line is ≤50 g / m 2, so it can reduce the self-weight of the transmission line and increase the flexibility of the transmission line, making the transmission line more flexible and easier to conform to the substrate, saving the use space.
[0038] Such as Figure 1 As shown, in one embodiment, the pore structure in the resin layer 22 of the present invention is air holes, for example, in shapes such as circular, oval, rectangular or irregular, and they can be evenly distributed in the resin layer 22.
[0039] Such as Figure 2 As shown, in another embodiment, the pore structure in the resin layer 22 of the present invention is air columns, the air columns penetrate through the resin layer 22, and both ends of the air columns are respectively sealed by the first adhesive layer 21 and the second adhesive layer 23. Preferably, the air columns are arranged in an array in the resin layer 22.
[0040] Optionally, the resin in the resin layer 22 is preferably at least one of polydimethylsiloxane (PDMS), polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), liquid crystal polymer (LCP) or polyimide (PI).
[0041] Optionally, the first adhesive layer 21 and the second adhesive layer 23 are respectively independently selected from at least one of a silicone adhesive layer, an epoxy adhesive layer or an acrylic adhesive layer.
[0042] In the transmission line of the present invention, the thickness of the formed dielectric layer 2 is preferably 0.04 mm - 1.1 mm, and the line width of the transmission line is preferably 0.1 mm - 5 mm. The present invention avoids increasing the line width by increasing the thickness of the dielectric layer 2 by reducing the dielectric constant of the dielectric layer 2, so that the dielectric layer 2 has a smaller thickness and the manufactured transmission line has a large line width.
[0043] In the dielectric layer 2, the thickness of the resin layer 22 is preferably 0.025 mm - 0.99 mm, the thickness of the first adhesive layer 21 is preferably 0.01 mm - 0.025 mm, and the thickness of the second adhesive layer 23 is preferably 0.01 mm - 0.025 mm.
[0044] Optionally, the transmission line layer 1 and the ground layer 3 are preferably flexible copper clad laminates. The flexible copper clad laminate includes a metal layer and a flexible film provided on the surface of the metal layer. The thickness of the metal layer is preferably 9 μm - 18 μm, the thickness of the flexible film is preferably 2 μm - 12.5 μm, the metal layer is preferably copper foil, and the flexible film is preferably at least one of a polyimide film or a polyester film.
[0045] The present invention also provides a preparation method of the transmission line as described above, including the following steps:
[0046] S1. Prepare a resin layer 22 with multiple pore structures;
[0047] S2. Use a flexible copper clad laminate to prepare a transmission line layer 1 and a ground layer 3, prepare a first semi-cured layer on the flexible film surface of the transmission line layer 1, and prepare a second semi-cured layer on the flexible film surface of the ground layer 3;
[0048] S3. Bond the two surfaces of the resin layer 22 to the first semi-cured layer and the second semi-cured layer respectively, and obtain a transmission line after curing.
[0049] In step S1, when preparing the resin layer 22 with multiple air holes, it is preferably to prepare a mixture of resin and pore-forming particles, cure and mold it, then dissolve the pore-forming particles to form air holes, and obtain the resin layer 22 with multiple air holes.
[0050] Preferably, the resin is selected from at least one of polydimethylsiloxane, polytetrafluoroethylene, polyetheretherketone, liquid crystal polymer or polyimide. The resin can be first prepared into a solution, and pore-forming particles are added to the solution to prepare a mixture. The mixture is cured and molded at 60°C - 250°C for 4h - 24h, and then the pore-forming particles are dissolved to form air holes. The shape of the air holes and their distribution in the resin layer 22 depend on the shape of the pore-forming particles and their dispersion state in the mixture. It can be understood that the air holes can be evenly dispersed in the resin layer 22, and the shapes of the air holes are round, oval, rectangular or irregular.
[0051] Preferably, the pore-forming particles are selected from at least one of sodium chloride, potassium chloride or sugar, with a size of 20nm - 500nm and a volume ratio in the mixture ≥ 90%, so that the volume ratio in the formed resin layer 22 ≥ 90%.
[0052] Alternatively, when preparing the resin layer 22 with multiple air columns, it is preferably to place the resin on a molding substrate, cure and mold it, and demold to obtain the resin layer 22 with multiple air columns.
[0053] Preferably, the resin is selected from at least one of polydimethylsiloxane, polytetrafluoroethylene, polyetheretherketone, liquid crystal polymer or polyimide. The resin can be first prepared into a solution, the solution is coated on a molding substrate, cured and molded at 60°C - 250°C for 4h - 24h, and then demolded to form air holes. Among them, the molding substrate contains multiple vertically distributed metal rods, so as to form multiple air columns in the resin layer 22.
[0054] Preferably, the diameter of the metal rod is 0.1 mm - 2 mm, and the total projected area of the metal rod on the molding substrate is not less than 90% of the area of the molding substrate, so that the volume ratio of the metal rod in the formed resin layer 22 is ≥90%.
[0055] In step S2, a flexible copper clad laminate is used to prepare the transmission line layer 1 and the ground layer 3, which can make the transmission line layer 1 and the ground layer 3 have good flexibility and is beneficial to improving the flexibility of the transmission line.
[0056] Semi-cured layers are respectively prepared on the surfaces of the transmission line layer 1 and the ground layer 3, and then the resin layer 22 is cured and bonded to the transmission line layer 1 and the ground layer 3 respectively through the semi-cured layers, which is beneficial to the fixation of the resin layer 22 with a large number of distributed pore structures between the transmission line layer 1 and the ground layer 3. Therefore, in step S2, an adhesive is coated on the side of the flexible film attached to the surfaces of the transmission line layer 1 and the ground layer 3 respectively, and pre-cured for 3 h - 6 h to form a first semi-cured layer and a second semi-cured layer, so as to reduce the fluidity of the adhesive. This can not only prevent it from flowing into the pore structures of the resin layer 22 and blocking the pore structures when contacting the resin layer 22 subsequently, but also improve the connection strength between the resin layer 22 and the transmission line layer 1 and the ground layer 2.
[0057] In step S3, the first semi-cured layer and the second semi-cured layer are respectively bonded to the two surfaces of the resin layer 22, and cured at 20°C - 25°C to obtain a transmission line.
[0058] Hereinafter, the transmission line and its manufacturing method will be further described through the following specific examples.
[0059] Example 1
[0060] NaCl particles are added to the PDMS solution to prepare a mixture. Among them, the dielectric constant of PDMS is 2.2, the size of the NaCl particles is 20 nm, and the volume content percentage of the NaCl particles in the mixture is 90%. After stirring evenly, it is cured at 60°C for 8 h to form a shape, and then ultrasonically soaked in warm water to dissolve the NaCl particles, forming a resin layer with a plurality of air holes, and the air holes are evenly distributed in the resin layer. Among them, the thickness of the resin layer is 0.03 mm.
[0061] The transmission line layer and the grounding layer with the required width and length are prepared using a flexible copper clad laminate. Among them, the thickness of the PI film of the flexible copper clad laminate is 12.5 μm, and the thickness of the copper foil is 9 μm. Then, epoxy adhesive is respectively coated on the PI film surfaces of the transmission line layer and the grounding layer. Among them, the dielectric constant of the epoxy adhesive is 4, and it is pre-cured for 3 h to respectively form a first semi-cured layer and a second semi-cured layer. Then, the opposite two sides of the first semi-cured layer and the second semi-cured layer are respectively bonded to the resin layer, and cured at 25 °C for 24 h to obtain a transmission line. Among them, the thickness of the first bonding layer is 0.01 mm, the thickness of the second bonding layer is 0.01 mm, and the thickness of the dielectric layer is 0.05 mm.
[0062] The performance of the transmission line in this embodiment is shown in Table 1.
[0063] Example 2
[0064] KCl particles are added to the PDMS solution to prepare a mixture. Among them, the dielectric constant of PDMS is 2.2, the size of the KCl particles is 500 nm, and the volume content percentage of the KCl particles in the mixture is 95%. After stirring evenly, it is cured at 100 °C for 6 h to form a shape, and then ultrasonically soaked in warm water to dissolve the KCl particles, forming a resin layer with multiple pores, and the pores are evenly distributed in the resin layer. Among them, the thickness of the resin layer is 0.95 mm.
[0065] The transmission line layer and the grounding layer with the required width and length are prepared using a flexible copper clad laminate. Among them, the thickness of the PI film of the flexible copper clad laminate is 12.5 μm, and the thickness of the copper foil is 18 μm. Then, silicone adhesive is respectively coated on the PI film surfaces of the transmission line layer and the grounding layer. Among them, the dielectric constant of the silicone adhesive is 3.5, and it is pre-cured for 6 h to respectively form a first semi-cured layer and a second semi-cured layer. Then, the opposite two sides of the first semi-cured layer and the second semi-cured layer are respectively bonded to the resin layer, and cured at 25 °C for 24 h to obtain a transmission line. Among them, the thickness of the first bonding layer is 0.025 mm, the thickness of the second bonding layer is 0.025 mm, and the thickness of the dielectric layer is 1 mm.
[0066] The performance of the transmission line in this embodiment is shown in Table 1.
[0067] Example 3
[0068] Sugar particles are added to the PDMS solution to prepare a mixture. Among them, the dielectric constant of PDMS is 2.2, the size of the sugar particles is 300 nm, and the volume content percentage of the sugar particles in the mixture is 96%. After stirring evenly, it is cured at 120 °C for 4 h to form a shape, and then ultrasonically soaked in warm water to dissolve the sugar particles, forming a resin layer with multiple pores, and the pores are evenly distributed in the resin layer. Among them, the thickness of the resin layer is 0.15 mm.
[0069] The transmission line layer and the grounding layer with the required width and length are prepared by using a flexible copper clad laminate. Among them, the thickness of the PI film of the flexible copper clad laminate is 2 μm, and the thickness of the copper foil is 9 μm. Then, acrylic adhesive is coated on the PI film surfaces of the transmission line layer and the grounding layer respectively. Among them, the dielectric constant of the acrylic adhesive is 3, and it is pre-cured for 6 h to form the first semi-cured layer and the second semi-cured layer respectively. Then, the opposite two sides of the first semi-cured layer and the second semi-cured layer are respectively bonded to the resin layer, and cured at 25 °C for 24 h to obtain the transmission line. Among them, the thickness of the first bonding layer is 0.025 mm, the thickness of the second bonding layer is 0.025 mm, and the thickness of the dielectric layer is 0.2 mm.
[0070] The performance of the transmission line in this embodiment is shown in Table 1.
[0071] Example 4
[0072] The PTFE solution is coated on the formed substrate. Among them, the dielectric constant of the PTFE is 2, the diameter of the metal rod of the formed substrate is 0.1 mm, the total projected area of the metal rods on the formed substrate accounts for 95% of the area of the formed substrate, and it is cured at 250 °C for 10 h to form, and then demolded to obtain a resin layer with a plurality of air columns, and the air columns penetrate through the resin layer. Among them, the thickness of the resin layer is 0.16 mm.
[0073] The transmission line layer and the grounding layer with the required width and length are prepared by using a flexible copper clad laminate. Among them, the thickness of the PI film of the flexible copper clad laminate is 2 μm, and the thickness of the copper foil is 18 μm. Then, epoxy adhesive is coated on the PI film surfaces of the transmission line layer and the grounding layer respectively. Among them, the dielectric constant of the epoxy adhesive is 4, and it is pre-cured for 6 h to form the first semi-cured layer and the second semi-cured layer respectively. Then, the opposite two sides of the first semi-cured layer and the second semi-cured layer are respectively bonded to the resin layer, and cured at 25 °C for 24 h to obtain the transmission line. Among them, the thickness of the first bonding layer is 0.02 mm, the thickness of the second bonding layer is 0.02 mm, and the thickness of the dielectric layer is 0.2 mm.
[0074] The performance of the transmission line in this embodiment is shown in Table 1.
[0075] Example 5
[0076] The PTFE solution is coated on the formed substrate. Among them, the dielectric constant of the PTFE is 2, the diameter of the metal rod of the formed substrate is 2 mm, the total projected area of the metal rods on the formed substrate accounts for 93% of the area of the formed substrate, and it is cured at 250 °C for 10 h to form, and then demolded to obtain a resin layer with a plurality of air columns, and the air columns penetrate through the resin layer. Among them, the thickness of the resin layer is 0.57 mm.
[0077] The transmission line layer and the grounding layer with the required width and length are prepared using a flexible copper clad laminate. Among them, the thickness of the PI film of the flexible copper clad laminate is 7 μm, and the thickness of the copper foil is 9 μm. Then, a silicone adhesive is coated on the PI film surfaces of the transmission line layer and the grounding layer. Among them, the dielectric constant of the silicone adhesive is 3.5, and it is pre-cured for 6 h to form the first semi-cured layer and the second semi-cured layer respectively. Then, the opposite sides of the first semi-cured layer and the second semi-cured layer are respectively bonded to the resin layer, and cured at 25 °C for 24 h to obtain a transmission line. Among them, the thickness of the first bonding layer is 0.015 mm, the thickness of the second bonding layer is 0.015 mm, and the thickness of the dielectric layer is 0.6 mm.
[0078] The performance of the transmission line in this embodiment is shown in Table 1.
[0079] Example 6
[0080] The PTFE solution is coated on the formed substrate. Among them, the dielectric constant of the PTFE is 2, the diameter of the metal rod of the formed substrate is 1 mm, and the total projected area of the metal rods on the formed substrate accounts for 96% of the area of the formed substrate. It is cured at 250 °C for 10 h to form, and then demolded to obtain a resin layer with a plurality of air columns, and the air columns penetrate through the resin layer. Among them, the thickness of the resin layer is 0.75 mm.
[0081] The transmission line layer and the grounding layer with the required width and length are prepared using a flexible copper clad laminate. Among them, the thickness of the PI film of the flexible copper clad laminate is 5 μm, and the thickness of the copper foil is 9 μm. Then, an acrylic adhesive is coated on the PI film surfaces of the transmission line layer and the grounding layer. Among them, the dielectric constant of the acrylic adhesive is 3, and it is pre-cured for 6 h to form the first semi-cured layer and the second semi-cured layer respectively. Then, the opposite sides of the first semi-cured layer and the second semi-cured layer are respectively bonded to the resin layer, and cured at 25 °C for 24 h to obtain a transmission line. Among them, the thickness of the first bonding layer is 0.025 mm, the thickness of the second bonding layer is 0.025 mm, and the thickness of the dielectric layer is 0.8 mm.
[0082] The performance of the transmission line in this embodiment is shown in Table 1.
[0083] Comparative Example 1
[0084] The difference between Comparative Example 1 and Example 1 is that: a silicone / ceramic particle composite adhesive is coated on the PI film surfaces of the transmission line layer and the grounding layer. Among them, the dielectric constant of the silicone / ceramic particle composite adhesive is 6, and it is pre-cured for 3 h to form the first semi-cured layer and the second semi-cured layer respectively. Then, the opposite sides of the first semi-cured layer and the second semi-cured layer are respectively bonded to the resin layer, and cured at 25 °C for 24 h to obtain a transmission line. Among them, the thickness of the first bonding layer is 0.01 mm, the thickness of the second bonding layer is 0.01 mm, and the thickness of the dielectric layer is 0.05 mm.
[0085] The performance of the transmission line in this comparative example is shown in Table 1.
[0086] Comparative Example 2
[0087] The difference between Comparative Example 2 and Example 1 is that NaCl particles are added to the PDMS solution to prepare a mixture. Among them, the dielectric constant of PDMS is 2.2, the size of the NaCl particles is 20 nm, and the volume content percentage of the NaCl particles in the mixture is 80%. In the fabricated transmission line, the thickness of the resin layer is 0.95 mm, and the thickness of the dielectric layer is 0.97 mm.
[0088] The performance of the transmission line in this comparative example is shown in Table 1.
[0089] Comparative Example 3
[0090] The difference between Comparative Example 3 and Example 1 is that NaCl particles are added to the PDMS / ceramic composite solution. In the fabricated transmission line, the dielectric constant of the PDMS / ceramic composite is 8, the thickness of the resin layer is 0.03 mm, and the thickness of the dielectric layer is 0.05 mm.
[0091] The performance of the transmission line in this comparative example is shown in Table 1.
[0092] Table 1
[0093]
[0094] As can be seen from Table 1, in Examples 1-6, the dielectric constant of the dielectric layer is less than or equal to 2. It can not only maintain the line width of the transmission line, improve the power bearing capacity of the transmission line, facilitate manufacturing, but also reduce the self-weight of the transmission line and increase the flexibility. From Comparative Examples 1-3, it can be seen that when the dielectric constant of the dielectric layer is greater than 2 and the thickness of the dielectric layer is not increased, the line width of the transmission line decreases, the power bearing capacity of the transmission line decreases, it is not convenient for manufacturing, and the self-weight of the transmission line increases and the flexibility decreases.
[0095] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.
[0096] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.
Claims
1. A transmission line, characterized in that, It includes a transmission line layer, a grounding layer, and a dielectric layer sandwiched between the transmission line layer and the grounding layer. Among them, the dielectric layer includes a resin layer with a plurality of pore structures, a first bonding layer, and a second bonding layer. The first bonding layer is sandwiched between the resin layer and the transmission line layer, and the second bonding layer is sandwiched between the resin layer and the grounding layer; and the dielectric layer also simultaneously satisfies the following conditions: (1) The dielectric constants of the first bonding layer and the second bonding layer are both less than or equal to 4; (2) The dielectric constant of the resin used in the resin layer is less than or equal to 3; (3) The volume ratio of the pore structures in the resin layer ≥ 90%; 2. The transmission line according to claim 1, wherein The pore structure is an air hole, and the air holes are distributed in the resin layer; Or, the pore structure is an air column, the air column penetrates through the resin layer, and both ends of the air column are respectively sealed by the first bonding layer and the second bonding layer.
3. The transmission line according to claim 1, wherein The resin is selected from at least one of polydimethylsiloxane, polytetrafluoroethylene, polyetheretherketone, liquid crystal polymer, or polyimide.
4. The transmission line according to claim 1, characterized in that, The first bonding layer and the second bonding layer are respectively independently selected from at least one of a silicone adhesive layer, an epoxy adhesive layer, or an acrylic adhesive layer.
5. The transmission line according to any one of claims 1-4, characterized in that, The thickness of the dielectric layer is 0.04 mm - 1.1 mm.
6. The transmission line according to claim 5, characterized in that, The thickness of the resin layer is 0.025 mm - 0.99 mm; And / or, the thicknesses of the first bonding layer and the second bonding layer are respectively independently selected from 0.01 mm - 0.025 mm.
7. The transmission line according to any one of claims 1-4, characterized in that, The line width of the transmission line is 0.1 mm - 5 mm.
8. A method for preparing a transmission line according to any one of claims 1-7, characterized in that, It includes the following steps: Preparing a resin layer with a plurality of pore structures; Using a flexible copper clad laminate to prepare a transmission line layer and a grounding layer, and preparing a first semi-cured layer on the flexible film surface of the transmission line layer and a second semi-cured layer on the flexible film surface of the grounding layer; Bonding the two surfaces of the resin layer to the first semi-cured layer and the second semi-cured layer respectively, and obtaining a transmission line after curing.
9. The manufacturing method of the transmission line according to claim 8, characterized in that, The step of preparing a resin layer with a plurality of pore structures includes: Formulating a mixture of resin and pore-forming particles and curing and molding, and then dissolving the pore-forming particles to form air holes, obtaining a resin layer with a plurality of air holes, wherein the volume ratio of the pore-forming particles in the mixture ≥ 90%; Or, placing the resin on a molding substrate and curing and molding, and demolding to obtain a resin layer with a plurality of air columns, wherein the molding substrate has a plurality of vertically distributed rods, and the total projected area of the rods on the molding substrate accounts for ≥ 90% of the area of the molding substrate.
10. The method for preparing a transmission line according to claim 9, wherein, The temperature for curing and molding is 60°C - 250°C, and the time is 4 h - 24 h.