High-frequency high-speed circuit board for 5G communication

Abstract

This invention discloses a high-frequency, high-speed circuit board for 5G communication, comprising: a circuit board formed by lamination, the circuit board including: multiple dielectric layers and line layers, the dielectric layers and line layers being arranged and laminated from bottom to top according to a certain order, thickness, and combination composition; the circuit board having vias for connecting the various line layers; the circuit board having mounting grooves, within which a shielding component is installed, and within the shielding component an antenna is installed, the high-frequency signal routing areas of the antenna being respectively located on two surface line layers; and the solder pads of the circuit board being surrounded by isolation pads. This achieves the protection of the high-frequency, high-speed characteristics of the circuit, while effectively improving antenna efficiency, reducing impedance abrupt changes in the circuit, and ensuring the overall strength of the circuit board.

Description

Technical Field

[0001] This invention relates to the field of PCB circuit board technology and equipment, and in particular to a high-frequency, high-speed circuit board for 5G communication. Background Technology

[0002] 5G millimeter wave technology is a fundamental technology in 5G applications. Millimeter waves are electromagnetic waves with wavelengths of 1-10 millimeters and frequencies ranging from 30GHz to 300GHz. They have advantages such as high bandwidth and low latency, but also disadvantages such as relatively weak propagation ability in the atmosphere and the need for more base stations. However, as wireless communication demands higher transmission rates, latency, and system capacity, the demand for high-frequency and high-speed PCBs used in 5G communication is also increasing.

[0003] For example, application number CN202011309295.2 discloses a millimeter-wave radar printed circuit board, which uses flat open-fiber glass braid as the dielectric layer material and designs the corresponding number of circuit board layers and layer structure to improve antenna efficiency.

[0004] However, the impedance abrupt changes and discontinuities of traces on both sides of the board in high-frequency and high-speed circuit boards also need to be mitigated. Furthermore, to reduce interference from power lines and logic signal lines to the antenna, some antenna circuit boards no longer integrate main power lines and logic signal lines (reducing the number of chips on the circuit board). Therefore, the number of layers in millimeter-wave high-frequency and high-speed circuit boards will decrease after the reduction in traces, and their layer structure will need to be adjusted accordingly. In particular, if the traces on the antenna circuit board are shortened, the impact of material loss on the traces will also be reduced for the same trace width. Therefore, there will be more material options available, and the layer structure design can be more flexible.

[0005] Therefore, there is an urgent need for a high-frequency, high-speed circuit board that can alleviate impedance abrupt changes, has a relatively smaller number of board layers, and can reduce the glass fiber effect. Summary of the Invention

[0006] To address one or more problems existing in the prior art, the present invention provides a high-frequency, high-speed circuit board for 5G communication. The technical solution adopted by the present invention to solve the above problems is: a high-frequency, high-speed circuit board for 5G communication, comprising: a circuit board, wherein the circuit board is provided with: a first line layer, a first dielectric layer, a second line layer, a second dielectric layer, and a third line layer from top to bottom; the circuit board is provided with vias penetrating the upper and lower end faces of the circuit board; the circuit board is provided with second vias; the circuit board is provided with mounting grooves, the mounting grooves penetrating the first line layer and partially extending into the first dielectric layer, and the depth of the grooves extending into the first dielectric layer is defined as L0;

[0007] The first dielectric layer is a combination layer of flat open-fiber glass woven fabric and modified resin, and a shielding layer is laminated onto the side of the first dielectric layer facing the second wire layer;

[0008] The first and third line layers are laminates made of rolled copper and are connected by fluorinated ethylene propylene copolymer as an adhesive sheet; the second line layer is a copper-plated laminate.

[0009] The second dielectric layer is a combination of flat open-fiber glass woven fabric and low-temperature co-fired ceramic particles, and a shielding layer is pressed onto the side of the second dielectric layer facing the second wire layer;

[0010] A shielding component is fixedly installed in the mounting groove. The shielding component is provided with a mounting groove, the edge of the mounting groove is provided with a cable inlet, and the top surface of the mounting groove is provided with a shielding layer.

[0011] The antenna is fixedly installed in the mounting slot. The antenna is electrically connected to the traces on the first line layer through the inlet. The high-frequency signal trace areas of the antenna are respectively located on the first line layer and the third line layer.

[0012] The first line layer, the second line layer, and the third line layer are electrically connected through the vias. The thickness of the second dielectric layer is L, and the thickness of the first dielectric layer is L+L0.

[0013] The end faces of the first line layer and the second line layer are each provided with a plurality of first pads, and the first pads are surrounded by isolation pads, the size of which is 40-50 mil;

[0014] The first line layer and the second line layer are electrically connected through the second via, and the third line layer is electrically connected to the second line layer through the second via. The pads of the second via on the first line layer and the third line layer surround the isolation pads.

[0015] In some embodiments, the second dielectric layer further includes a polymeric resin.

[0016] In some embodiments, the circuit board is provided with a recessed hole, which is provided on the first line layer and / or the third line layer. Impedance change components are installed in the recessed hole, including capacitors and inductors. A first via may be provided on the bottom surface of the recessed hole, which is connected to the second line layer. The impedance change components are electrically connected to the lines on the second line layer through the first via.

[0017] In some embodiments, the thicknesses of the first line layer, the second line layer, the third line layer, and the second dielectric layer are equal.

[0018] The beneficial value of this invention is as follows: By pressing the first, second, and third line layers and the first and second dielectric layers into a circuit board, and using the provided isolation pads and recessed vias (ground vias), this invention achieves a reduction in dielectric constant by using flat open-fiber woven fabric as the dielectric layer material, thereby improving antenna performance. Simultaneously, it reduces the impedance abrupt change in the two continuous line regions exposed to air on the circuit board (the line regions on the first and second line layers), thus improving high-frequency and high-speed signal performance. By optimizing the via design to control impedance, the amplitude of impedance abrupt changes is further reduced. Isolation references (recessed vias) are provided for components such as capacitors and inductors, which are prone to impedance abrupt changes, so that impedance abrupt changes are minimized when lines pass through these components. To improve the performance of high-frequency and high-speed antenna signals, some circuit boards no longer have main power lines and main logic signal lines on the circuit board (reducing the number of chips), meaning that what was originally one board is used as two boards. Such circuit boards, through the structure of this invention, can maintain a smaller size and achieve a smoother impedance abrupt change curve. All of the above greatly enhances the practical value of this invention. Attached Figure Description

[0019] Figure 1 This is a top view of the present invention;

[0020] Figure 2 This is a cross-sectional view of the present invention.

[0021] [Attached image labels]

[0022] 1. Circuit Board

[0023] 11··· Installation groove

[0024] 2··· Shielding components

[0025] 3. Upper layer cabling area

[0026] 4··· Vias

[0027] 41···First isolation pad

[0028] 5··· First pad

[0029] 6··· Concave hole

[0030] 7. Impedance Sudden Change Components

[0031] 8··· First Through Hole

[0032] 9··· Second via

[0033] 91···Second Isolation Pad

[0034] 10···First Line Layer

[0035] 20···First Dielectric Layer

[0036] 30···Second line layer

[0037] 40···Second Dielectric Layer

[0038] 50···Third line layer. Detailed Implementation

[0039] To make the above-mentioned objects, features, and advantages of the present invention more readily understood, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0040] In particular, it should be noted that the scale of the attached diagram has been exaggerated in order to better illustrate the hierarchical structure of the circuit board, and the positions of vias and components have also been appropriately adjusted for ease of demonstration.

[0041] like Figure 1 , Figure 2 As shown, this invention discloses a high-frequency, high-speed circuit board for 5G communication, comprising: a circuit board 1, wherein the circuit board 1 is provided with, from top to bottom: a first line layer 10, a first dielectric layer 20, a second line layer 30, a second dielectric layer 40, and a third line layer 50; the circuit board 1 is provided with a via 4, the via 4 penetrating the upper and lower end faces of the circuit board 1; the circuit board 1 is provided with a second via 9; the circuit board 1 is provided with a mounting groove 11, the mounting groove 11 penetrating the first line layer 10 and partially excavating into the first dielectric layer 20, and the depth of excavation into the first dielectric layer 20 is denoted as L0;

[0042] The first dielectric layer 20 is a combination layer of flat open-fiber glass woven fabric and modified resin, and a shielding layer is pressed onto the side of the first dielectric layer 20 facing the second wire layer 30.

[0043] The second dielectric layer 40 is a combination layer of flat open-fiber glass woven cloth and low-temperature co-fired ceramic particles. A shielding layer is pressed onto the side of the second dielectric layer 40 facing the second line layer 30. Together with the shielding layer pressed onto the side of the first dielectric layer 20 facing the second line layer 30, the second line layer 30 in the middle can achieve a better shielding effect. Furthermore, the two mesh shielding layers in the middle can make the overall strength of the circuit board 1 higher.

[0044] The first line layer 10 and the third line layer 50 are laminates made of rolled copper and are connected by fluorinated ethylene propylene copolymer as an adhesive sheet; the second line layer 30 is a copper-plated laminate.

[0045] The shielding component 2 is fixedly installed in the mounting groove 11. The shielding component 2 is provided with a mounting groove, the edge of the mounting groove is provided with a cable inlet, and the top surface of the mounting groove is provided with a shielding layer.

[0046] The antenna is fixedly installed in the mounting slot. The antenna is electrically connected to the traces on the first line layer 10 through the inlet. The high-frequency signal trace areas of the antenna are respectively located on the first line layer 10 and the third line layer 50.

[0047] The first line layer 10, the second line layer 30, and the third line layer 50 are electrically connected through the via 4. The thickness of the second dielectric layer 40 is L, and the thickness of the first dielectric layer 20 is L+L0.

[0048] The end faces of the first line layer 10 and the second line layer 30 are each provided with a plurality of first pads 5, and the first pads 5 are surrounded by isolation pads, the size of which is 40-50 mil;

[0049] The first line layer 10 and the second line layer 30 are electrically connected through the second via 9, and the third line layer 50 and the second line layer 30 are electrically connected through the second via 9. Figure 2 (Not specified, but its principle is the same as the above-mentioned first line layer setting method), the second via 9 is provided on the pads of the first line layer 10 and the third line layer 50, which surround the isolation pads, that is Figure 2 The second isolation pad 91 in the second via 9 is provided on the pad of the second line layer 30, and the isolation pad may also be surrounded by the second via 9.

[0050] Similarly, the via 4, located on the first line layer 10 and the third line layer 50, also surrounds the isolation pad, i.e. Figure 2 The first isolation pad 41 in the middle.

[0051] It should be noted that the antenna's performance is primarily affected by the dielectric constant of the materials on the circuit board 1. Generally, the smaller the dielectric constant of the conductor, the further away from the glass fiber, the better the antenna's performance. For example, using TU_872LK low dielectric constant (3.8) material from TaiYao can achieve an even lower dielectric constant, but the cost is relatively higher. Furthermore, some PCBs incorporate high-frequency ceramics to achieve good high-frequency and high-speed characteristics, and the dielectric constant of high-frequency ceramic PCBs is generally above 5.0. Due to their inherent characteristics, millimeter waves experience severe attenuation during atmospheric propagation, meaning the operating range of millimeter-wave antennas is relatively small. Given the large number of antennas deployed, achieving good performance and excellent high-frequency and high-speed characteristics within a limited operating range is sufficient. Therefore, such antennas do not require extremely low dielectric constants, but the circuit board has high requirements for high frequency and high speed.

[0052] Flat open-fiber woven glass fabric mainly refers to glass fabric using this weaving method, such as PTFE polytetrafluoroethylene in type 1078 glass fabric, PTFE polytetrafluoroethylene in type 1080 glass fabric, and ceramic-filled non-PTFE laminate in type 1080 glass fabric. Compared to standard weaving methods, flat open-fiber woven fabric has a lower dielectric constant, which can improve antenna efficiency, and its cost is lower than that of TU_872LK material. The dielectric constant of flat open-fiber woven glass fabric is around 4.4, which is lower than that of traditional standard weaving but higher than that of TU_872LK material, and is close to that of high-frequency ceramics and low-temperature co-fired ceramic particles (dielectric constant around 5.0, some can be lower than 5.0).

[0053] Therefore, using flat open-fiber glass woven fabric offers a higher cost-performance ratio compared to TU_872LK material.

[0054] It should be noted that the function of the isolation pad is to optimize the impedance at the solder joint, making the impedance change amplitude smaller. The first line layer 10 and the third line layer 50 are rolled copper. The first line layer 10 and the third line layer 50 are high-frequency, high-speed line layers in contact with air. The smooth rolled copper can enable the circuit to achieve lower impedance change characteristics and reduce loss under the skin effect. The second line layer 30, as an intermediate line layer, can be copper plated to achieve relatively low impedance change and control costs.

[0055] The mounting groove 11 penetrates the first line layer 10 and partially extends into the first dielectric layer 20, which is a combination layer of flat open-fiber woven glass cloth and modified resin. The purpose is to achieve a lower dielectric constant near the antenna and to allow the shielding member 2 to be more securely mounted on the relatively thin circuit board 1. The modified resin on the surface aids in adhesion.

[0056] Specifically, the first line layer 10, the second line layer 30, the third line layer 50, and the second dielectric layer 40 have equal thicknesses. The thickness of the second dielectric layer 40 is L, and the thickness of the first dielectric layer 20 is L+L0. This is to make the mechanical properties of each layer of the board more consistent, thereby improving antenna efficiency. The extra L0 in the first dielectric layer 20 is to facilitate the placement of the mounting groove 11. In particular, the second dielectric layer 40 also includes polymer resin to improve its own strength and the connection strength of the shielding layer pressed against the side facing the second line layer 30.

[0057] like Figure 1 , Figure 2 As shown, the circuit board 1 has a recessed via 6 / ground via. The recessed via 6 is located on the first line layer 10 and / or the third line layer 50. Impedance change components 7 are installed within the recessed via 6, including capacitors and inductors. The purpose is to provide isolation references for individual components (such as coupling capacitors) to minimize impedance changes, i.e., to bring the components closer to the reference plane of the transmission line, resulting in smaller impedance variations. Furthermore, a first via 8 can be provided on the bottom surface of the recessed via 6. The first via 8 is connected to the second line layer 30, and the impedance change components 7 are electrically connected to the lines on the second line layer 30 through the first via 8.

[0058] It should be noted that the chips, circuits, and other traces on the circuit board 1, as well as the components, are based on existing commonly used technologies (see reference for placement). Figure 1 The upper-layer cabling area 3) can be flexibly changed according to requirements, and the result of such change can be directly predicted. Therefore, it will not be elaborated on here.

[0059] Specifically, the second dielectric layer 40 is a combination layer of flat open-fiber glass woven fabric and low-temperature co-fired ceramic particles. The purpose is to enable the third line layer 50, which serves as the main high-frequency and high-speed signal line, to achieve excellent high-frequency and high-speed characteristics in order to meet transmission requirements and antenna performance requirements.

[0060] In summary, this invention, by pressing the first, second, and third line layers and the first and second dielectric layers into a circuit board, and using the provided isolation pads and recessed vias (ground vias), achieves a reduction in dielectric constant by using flat open-fiber woven fabric as the dielectric layer material, thereby improving antenna performance. Simultaneously, it reduces the impedance abrupt change in the two continuous line regions exposed to air on the circuit board (the line regions on the first and second line layers), thus improving high-frequency and high-speed signal performance. By optimizing the via design to control impedance, the amplitude of impedance abrupt changes is further reduced. Isolation references (recessed vias) are provided for components such as capacitors and inductors, which are prone to impedance abrupt changes, so that impedance abrupt changes are minimized when lines pass through these components. To improve the performance of high-frequency and high-speed antenna signals, some circuit boards no longer have main power lines and main logic signal lines (reducing the number of chips), effectively using two boards instead of one. Such circuit boards, through the structure of this invention, can maintain a smaller size and achieve a smoother impedance abrupt change curve. All of these significantly enhance the practical value of this invention.

[0061] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions.

[0062] The embodiments described above are merely illustrative of one or more implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A high-frequency, high-speed circuit board for 5G communication, characterized in that, include: A circuit board, comprising, from top to bottom: a first line layer, a first dielectric layer, a second line layer, a second dielectric layer, and a third line layer; the circuit board has vias that penetrate the upper and lower end faces of the circuit board; the circuit board has second vias; and the circuit board has mounting grooves that penetrate the first line layer and partially extend into the first dielectric layer, with the depth of the grooves extending into the first dielectric layer being defined as L0. The first dielectric layer is a combination layer of flat open-fiber glass woven fabric and modified resin, and a shielding layer is laminated onto the side of the first dielectric layer facing the second wire layer; The first and third line layers are laminates made of rolled copper and are connected by fluorinated ethylene propylene copolymer as an adhesive sheet; the second line layer is a copper-plated laminate. The second dielectric layer is a combination of flat open-fiber glass woven fabric and low-temperature co-fired ceramic particles, and a shielding layer is pressed onto the side of the second dielectric layer facing the second wire layer; A shielding component is fixedly installed in the mounting groove. The shielding component is provided with a mounting groove, the edge of the mounting groove is provided with a cable inlet, and the top surface of the mounting groove is provided with a shielding layer. The antenna is fixedly installed in the mounting slot. The antenna is electrically connected to the traces on the first line layer through the inlet. The high-frequency signal trace areas of the antenna are respectively located on the first line layer and the third line layer. The first line layer, the second line layer, and the third line layer are electrically connected through the vias. The thickness of the second dielectric layer is L, and the thickness of the first dielectric layer is L+L0. The end faces of the first line layer and the second line layer are each provided with a plurality of first pads, and the first pads are surrounded by isolation pads, the size of which is 40-50 mil; The first line layer and the second line layer are electrically connected through the second via, and the third line layer is electrically connected to the second line layer through the second via. The pads of the second via on the first line layer and the third line layer surround the isolation pads.

2. The high-frequency, high-speed circuit board for 5G communication according to claim 1, characterized in that, The second dielectric layer also includes a polymeric resin.

3. The high-frequency, high-speed circuit board for 5G communication according to claim 1, characterized in that, The circuit board has recessed holes located on the first line layer and / or the third line layer. Impedance change components are installed in the recessed holes, including capacitors and inductors.

4. The high-frequency, high-speed circuit board for 5G communication according to claim 3, characterized in that, The bottom surface of the recessed hole may be provided with a first via, which is connected to the second line layer. The impedance change component is electrically connected to the line on the second line layer through the first via.

5. A high-frequency, high-speed circuit board for 5G communication according to claim 1, characterized in that, The thicknesses of the first line layer, the second line layer, the third line layer, and the second dielectric layer are equal.

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