Method and system for calculating differential impedance of mesh shielding structure, device and medium

Abstract

The application discloses a kind of grid shielding structure differential impedance calculation method and system, equipment, medium, the method is based on the conductor width and pitch of grid shielding layer first Calculation obtains escape ratio, then signal escape radiation is equivalent to the increase of dielectric thickness farther, to calculate equivalent dielectric thickness, based on time equivalence principle Calculation obtains the equivalent dielectric constant between electric ground, finally calculates differential impedance.The application first proposes the calculation theory and calculation model of grid shielding structure differential impedance, considers the influence of the escape effect of grid shielding layer on differential impedance calculation, by the signal escape of grid shielding layer is equivalent to the increase of dielectric thickness, and based on time equivalence principle Calculation equivalent dielectric constant, different from the dielectric constant of pure dielectric between transmission line, greatly improve the precision of grid shielding structure differential impedance calculation, can be well applied to the differential line design of grid shielding structure, is conducive to improving the first pass rate of differential impedance design.

Description

Technical Field

[0001] This invention relates to the field of differential impedance calculation technology, and in particular, to a differential impedance calculation method and system for a mesh-shielded structure, an electronic device, and a computer-readable storage medium. Background Technology

[0002] With the rapid development of the communications industry, signal transmission speeds are increasing, and the requirements for operating frequencies and transmission quality are becoming more stringent. Simultaneously, the types and characteristics of high-speed transmission structures are becoming more diverse. On FPC boards, to improve the substrate's bendability and prevent cracking of the large copper shielding layer during bending, the shielding layer is often designed in a mesh pattern, thereby improving the substrate's toughness. In high-frequency signal transmission, the signal layer (i.e., the wiring layer) and the ground layer (i.e., the shielding layer) are transmitted via high-frequency electromagnetic radiation. Based on the classic characteristic impedance line transmission and TDR (time domain reflection) measurement principles, a high-frequency signal is emitted from the signal line. The signal not only propagates forward along the conductor but also radiates to the ground plane. The induced signal received through the ground plane returns to the measurement end (the measurement and transmission ends share a common port). The line impedance value is calculated by the level intensity of the emitted and reflected signals. Generally, reflectivity is expressed as ρ = V. reflected / V incident This indicates that the measured impedance Z = Z ref The value is measured using *(1+ρ) / (1-ρ), where ρ is the signal reflectivity and V is the signal reflectivity. reflected The level strength of the reflected received signal, V incident Z represents the level strength of the transmitted signal. ref The reference resistance, typically 50 ohms, represents the standard. For large metal shielding structures, the reflection path on the large copper surface is the same length as the transmission cable, and the signal strength loss due to reflection mainly comes from dielectric loss and conductor surface loss. During impedance design, the classic differential microstrip line characteristic impedance calculation formula is generally used to calculate the characteristic impedance of differential microstrip lines with large copper shielding structures. The classic differential microstrip line characteristic impedance calculation formula is as follows: Z0 represents the characteristic impedance of a classic single-ended microstrip line. Where, ε r denoted by , h represents the dielectric constant of the dielectric layer, t represents the copper thickness of the single-ended microstrip line, w represents the width of the single-ended microstrip line, and d represents the edge spacing between two single-ended microstrip lines.

[0003] However, for mesh shielding structures, after the reflected signal is received by the mesh shielding layer with holes, the electromagnetic signal lines are distributed uniformly in the local space. That is, dφ tends to be uniformly distributed within a single square region (a+b squares, where a represents the conductor width of the mesh shielding layer and b represents the spacing between conductors in the mesh shielding layer). Therefore, when the signal is transmitted to the shielding layer, part of it is received and returned, while the other part is radiated out and dissipated through the mesh holes, resulting in a change in the strength of the returned signal and thus affecting the calculation of the impedance value. Therefore, the classical formula for calculating the characteristic impedance of differential microstrip lines is not applicable to mesh shielding structures. Summary of the Invention

[0004] This invention provides a method and system for calculating the differential impedance of a mesh-shielded structure, as well as an electronic device and a computer-readable storage medium, to solve the technical problem that the existing classical differential microstrip line characteristic impedance calculation formula is not applicable to mesh-shielded structures.

[0005] According to one aspect of the present invention, a method for calculating the differential impedance of a mesh shielding structure is provided, comprising the following:

[0006] Obtain the conductor width and spacing of the mesh shielding layer, and calculate the ratio of signal escaping from the mesh shielding layer to signal transmission from the ground layer.

[0007] Obtain the dielectric thickness parameters of the dielectric layer, and equate the signal dissipation of the mesh shielding layer to an increase in dielectric thickness. Calculate the equivalent dielectric thickness based on the dissipation ratio and dielectric thickness parameters.

[0008] Obtain the angle between the differential line and the horizontal edge of the grid shielding layer, and the dielectric constant of the dielectric layer. Calculate the equivalent dielectric constant based on the principle of equivalent transmission time in the ground loop network.

[0009] The differential impedance is calculated by obtaining the linewidth, copper thickness, and edge spacing between the two differential lines, and then combining the equivalent dielectric thickness, equivalent dielectric constant, and the classical differential microstrip line characteristic impedance calculation formula.

[0010] Furthermore, the differential impedance is calculated based on the following formula:

[0011]

[0012] Where Z2 represents the differential impedance of the mesh shielding structure, ε r ' represents the equivalent dielectric constant, ε r denoted by , h′ represents the equivalent dielectric thickness, w and t represent the linewidth and copper thickness of the differential lines, and d represents the edge spacing between the two differential lines.

[0013] Furthermore, a curved segment is designed on one of the differential lines, with the span and height of the curved segment being smaller than the spacing of the mesh shielding layer.

[0014] Furthermore, the process of calculating the dissipation ratio is as follows:

[0015] Since the electromagnetic signal lines are uniformly distributed within a single grid area, the actual signal dissipation within that single grid area is proportional to the dissipation of the transmitted signal, i.e., η = φ1 / φ 总 =S1 / S 总 Where η represents the dissipation ratio, φ1 and φ 总 S1 and S2 represent signal dissipation and signal transmission, respectively. 总 Let S1 and b represent the area of ​​the holes in a single grid region and the total area, respectively, where S1 = b 2 S 总 = (a+b) 2 Let a and b represent the conductor width and spacing of the mesh shielding layer, respectively.

[0016]

[0017] Furthermore, the equivalent dielectric thickness is calculated based on the following formula:

[0018]

[0019] Where h′ represents the equivalent dielectric thickness, and h represents the dielectric thickness parameter of the dielectric layer.

[0020] Furthermore, the process of calculating the equivalent dielectric constant based on the principle of equivalent transmission time in the electric ground loop network is as follows:

[0021] In a single grid, the actual transmission time of the electrical signal is t = (1 + cosθ + sinθ)l / v. c represents the speed of light, ε r Let θ represent the dielectric constant of the dielectric layer, θ represent the angle between the differential line and the horizontal edge of the grid shielding layer, and l represent the length of the hypotenuse of a single grid. Based on the principle of equivalent transmission time in the ground loop network, assuming a transmission length of 2l, then... ε′ r Represents the equivalent dielectric constant, thus

[0022]

[0023] Furthermore, the overall width of the mesh shielding layer is infinitely wide relative to the differential lines; or, the mesh shielding layer is at least three times thicker and three times wider on each side than the differential lines in the width direction.

[0024] In addition, the present invention also provides a differential impedance calculation system for a mesh shielded structure, comprising:

[0025] The dissipation ratio calculation module is used to obtain the conductor width and spacing of the mesh shielding layer and calculate the dissipation ratio of the signal dissipation of the mesh shielding layer relative to the signal transmission of the ground layer.

[0026] The equivalent dielectric thickness calculation module is used to obtain the dielectric thickness parameters of the dielectric layer, and to equate the signal dissipation of the mesh shielding layer to the increase in dielectric thickness. The equivalent dielectric thickness is calculated based on the dissipation ratio and the dielectric thickness parameters.

[0027] The equivalent dielectric constant calculation module is used to obtain the angle between the differential line and the horizontal edge of the grid shielding layer, the dielectric constant of the dielectric layer, and to calculate the equivalent dielectric constant based on the principle of equivalent transmission time of the ground loop network.

[0028] The differential impedance calculation module is used to obtain the linewidth, copper thickness, and edge spacing between two differential lines, and calculate the differential impedance by combining the equivalent dielectric thickness, equivalent dielectric constant, and the classical differential microstrip line characteristic impedance calculation formula.

[0029] In addition, the present invention also provides an electronic device, including a processor and a memory, wherein the memory stores a computer program, and the processor executes the steps of the method described above by calling the computer program stored in the memory.

[0030] In addition, the present invention provides a computer-readable storage medium for storing a computer program for calculating the differential impedance of a mesh shielding structure, wherein the computer program executes the steps of the method described above when run on a computer.

[0031] The present invention has the following effects:

[0032] The differential impedance calculation method for the mesh shielding structure of this invention considers that after a signal is transmitted to the mesh shielding layer, part of the signal is received and returned by the mesh shielding layer, while another part is radiated out and dissipated through the mesh holes of the mesh shielding layer, which causes changes in the strength of the returned signal and thus affects the accuracy of the impedance calculation. Therefore, this invention first calculates the dissipation ratio of the signal dissipation of the mesh shielding layer relative to the signal transmission of the ground layer based on the conductor width and spacing of the mesh shielding layer. Then, it equates the signal dissipation of the mesh shielding layer to the increase in the dielectric thickness of the dielectric layer, thereby calculating the equivalent dielectric thickness based on the dissipation ratio and dielectric thickness parameters. Next, it calculates the equivalent dielectric constant of the mesh shielding structure compared to the large copper shielding layer based on the principle of equivalent transmission time of the ground layer loop network, which is different from the dielectric constant of the pure dielectric between transmission lines. Finally, it calculates the differential impedance of the mesh shielding structure by combining the linewidth of the differential line, the copper thickness, the edge spacing between the two differential lines, the equivalent dielectric thickness, the equivalent dielectric constant, and the classical differential microstrip line characteristic impedance calculation formula of the large copper shielding layer. This invention proposes for the first time a calculation theory and model for the differential impedance of a mesh shielded structure. It takes into account the influence of the dissipation effect of the mesh shielding layer on the differential impedance calculation. By equating the signal dissipation of the mesh shielding layer to an increase in dielectric thickness, and by calculating the equivalent dielectric constant of the mesh shielding structure compared to the large copper surface shielding layer based on the principle of equivalent transmission time of the ground loop network, the accuracy of the differential impedance calculation of the mesh shielding structure is greatly improved. It can be well applied to the differential line design of the mesh shielding structure and is conducive to improving the first-pass yield of differential impedance design.

[0033] In addition, the differential impedance calculation system, electronic device, and computer-readable storage medium of the mesh shielding structure of the present invention also have the above-mentioned advantages.

[0034] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0035] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0036] Figure 1 This is a cross-sectional schematic diagram of the mesh shielding structure according to a preferred embodiment of the present invention.

[0037] Figure 2 This is a schematic diagram of a preferred embodiment of the present invention, showing that the differential lines are set at an angle to the horizontal edge of the mesh shielding layer.

[0038] Figure 3This is a flowchart illustrating the differential impedance calculation method for a mesh shielding structure according to a preferred embodiment of the present invention.

[0039] Figure 4 This is a schematic diagram of a curve segment designed on one of the differential lines in a preferred embodiment of the present invention.

[0040] Figure 5 This is a schematic diagram of the module structure of a differential impedance calculation system with a mesh shielding structure according to another embodiment of the present invention. Detailed Implementation

[0041] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0042] It is understood that a preferred embodiment of the present invention provides a method for calculating the differential impedance of a mesh shielding structure, wherein, as... Figure 1 and Figure 2 As shown, the impedance line structure with a mesh shielding structure specifically includes a wiring layer, a dielectric layer, and a mesh shielding layer. The wiring layer and the mesh shielding layer are respectively disposed on both sides of the dielectric layer. The wiring layer is designed with two differential lines, typically two single-ended microstrip lines. The mesh shielding layer is an orthogonal square grid conductor. Optionally, the mesh shielding layer is infinitely wide relative to the differential lines in the width direction; or, the mesh shielding layer is at least three times the dielectric thickness and three times the line width on one side of the differential lines in the width direction. Figure 3 As shown, the differential impedance calculation method for the mesh shielding structure specifically includes the following:

[0043] Step S1: Obtain the conductor width and spacing of the mesh shielding layer, and calculate the ratio of signal escaping from the mesh shielding layer to signal transmission from the ground layer;

[0044] Step S2: Obtain the dielectric thickness parameters of the dielectric layer, and convert the signal dissipation of the mesh shielding layer into an increase in dielectric thickness. Calculate the equivalent dielectric thickness based on the dissipation ratio and dielectric thickness parameters.

[0045] Step S3: Obtain the angle between the differential line and the horizontal edge of the grid shielding layer, and the dielectric constant of the dielectric layer. Calculate the equivalent dielectric constant based on the principle of equivalent transmission time in the ground loop network.

[0046] Step S4: Obtain the linewidth, copper thickness, and edge spacing between the two differential lines, and calculate the differential impedance by combining the equivalent dielectric thickness, equivalent dielectric constant, and the classical differential microstrip line characteristic impedance calculation formula.

[0047] It is understood that the differential impedance calculation method for the mesh shielding structure in this embodiment takes into account that after the signal is transmitted to the mesh shielding layer, part of the signal is received and returned by the mesh shielding layer, while another part is radiated out and dissipated through the mesh holes of the mesh shielding layer, which will cause the return signal strength to change, thus affecting the accuracy of the impedance value calculation. Therefore, this invention first calculates the dissipation ratio of the signal dissipation of the mesh shielding layer relative to the signal transmission of the ground layer based on the conductor width and spacing of the mesh shielding layer. Then, it equates the signal dissipation of the mesh shielding layer to the increase in dielectric thickness of the dielectric layer, and calculates the equivalent dielectric thickness based on the dissipation ratio and dielectric thickness parameters. Then, it calculates the equivalent dielectric constant between the mesh shielding structure and the ground layer compared to the large copper shielding layer based on the principle of equivalent transmission time of the ground layer loop network. Finally, it calculates the differential impedance of the mesh shielding structure by combining the linewidth of the differential line, copper thickness, edge spacing between the two differential lines, equivalent dielectric thickness, equivalent dielectric constant, and the classical differential microstrip line characteristic impedance calculation formula of the large copper shielding layer. This invention proposes for the first time a calculation theory and model for differential impedance of a mesh shielded structure. It takes into account the influence of the dissipation effect of the mesh shielding layer on the differential impedance calculation. By equating the signal dissipation of the mesh shielding layer to an increase in dielectric thickness, and based on the principle of equivalent transmission time of the ground loop network, it calculates the equivalent dielectric constant of the mesh shielding structure compared to the large copper shielding layer, which is different from the dielectric constant of the pure dielectric between transmission lines. This greatly improves the accuracy of differential impedance calculation for the mesh shielding structure and can be well applied to the design of differential lines with mesh shielding structures, which is conducive to improving the first-pass yield of differential impedance design.

[0048] It can be understood that in step S1, since the electromagnetic signal lines are uniformly distributed within a single grid area (i.e., a+b squares) in the grid shielding layer, the actual signal dissipation within a single grid area relative to the signal transmission amount is proportional to the receiving area after the signal is transmitted to the grid shielding layer. Wherein, φ1 and φ 总 S1 and S2 represent signal dissipation and signal transmission, respectively. 总 ...

[0049]

[0050] Where η represents the dissipation ratio.

[0051] It is understood that in step S2, the characteristic impedance of a single-ended microstrip line with a large copper shielding layer is calculated using the classic formula: It can be seen that the characteristic impedance Z0 of a single-ended microstrip line is related to the linewidth w, copper thickness t, and dielectric constant ε of the dielectric layer. r The signal reception is inversely proportional to the dielectric thickness h; the larger the dielectric thickness h, the less signal is received. Signal reception is directly related to the distance between the dielectric and ground planes (i.e., the distance from the dielectric layer to the grid shielding layer). Increasing the grid thickness is equivalent to increasing the dielectric thickness distance. Therefore, replacing the large copper shielding layer with a grid shielding layer can be equivalent to increasing the dielectric thickness. Thus, the equivalent dielectric thickness can be calculated based on the following formula:

[0052]

[0053] Where h′ represents the equivalent dielectric thickness, h represents the dielectric thickness parameter of the dielectric layer, and η represents the dissipation ratio.

[0054] It is understandable that in step S3, from the perspective of the ground loop, the characteristic impedance transmission cable still appears as a straight line in the dielectric layer, but the transmission path of the grid shielding layer is affected by the angle between the transmission line and the grid. Specifically, in a single grid, the signal is transmitted along the right-angled side of the single grid. According to the relationship between the hypotenuse and the shorter side of a right triangle, the signal transmission length of the grid shielding layer is: l(cosθ+sinθ), where θ represents the angle between the differential line and the horizontal side of the grid shielding layer, and l represents the length of the hypotenuse of the right triangle. Combining this with the transmission speed of the electrical signal in the medium: c represents the speed of light, ε r Let represent the dielectric constant of the dielectric layer. Therefore, the actual transmission time of the electrical signal is t = (1 + cosθ + sinθ)l / v. According to the principle of equivalent transmission time in the electric ground loop network, assuming a transmission length of 2l, then... ε′ r Representing the equivalent dielectric constant, we can calculate:

[0055] Differential impedance, also known as differential-mode impedance, comprises the superposition of the characteristic impedances of two single-ended microstrip lines, as well as the common-coupling attenuation caused by differential-mode induction between the two lines. Essentially, the first part represents the impedance to ground, and the second part represents the attenuation of the impedance from one differential line to the other. From the classic formula for calculating the differential impedance of a large copper shielded layer differential microstrip line:

[0056]

[0057] Where Z1 represents the differential impedance of the large copper shielding layer structure, ε r denoted by , h represents the dielectric constant of the dielectric layer, h represents the thickness of the dielectric layer (abbreviated as dielectric thickness), w and t represent the linewidth and copper thickness of the differential lines, and d represents the edge spacing between the two differential lines.

[0058] The above formula can be broken down as follows:

[0059]

[0060] in, This indicates that the characteristic impedances of the two single-ended microstrip lines are superimposed, and This represents the equivalent characteristic impedance attenuation value between two single-ended microstrip lines.

[0061] For a mesh shielding structure, signal leakage occurs due to voids in the mesh shielding layer. This leakage needs to be equivalent to an increase in dielectric thickness. Furthermore, the characteristic impedance of each single-ended microstrip line is calculated using the ground plane loop transmission. Therefore, when calculating the superposition of the characteristic impedances of two single-ended microstrip lines, equivalent dielectric thickness and equivalent dielectric constant are required. However, the differential-mode induction between two single-ended microstrip lines exists only in the electrical layer (i.e., the wiring layer) and is unaffected by the shielding structure. Therefore, when calculating the attenuation of the equivalent characteristic impedance between two single-ended microstrip lines, the effect of the equivalent dielectric constant is not considered; only the effect of the equivalent dielectric thickness is taken into account. Therefore, in step S4, the differential impedance of the mesh shielding structure is specifically calculated using the following formula:

[0062]

[0063] Where Z2 represents the differential impedance of the mesh shielding structure, ε r ′ represents the equivalent dielectric constant, and h′ represents the equivalent dielectric thickness.

[0064] Then, the equivalent dielectric thickness h′ and the equivalent dielectric constant ε′ are... r Substituting into the above formula, we get:

[0065]

[0066] Where Z2 represents the differential impedance of the mesh shielding structure.

[0067] It is understandable that, in order to ensure consistent transmission delay between differential mode and differential ground, and to reduce the impact of the mesh shielding layer, a curved segment is designed on one of the differential lines, such as... Figure 4 As shown, the span and height of the curve segment are both less than the spacing b of the mesh shielding layer.

[0068] It is understood that, in order to verify the calculation accuracy of the differential impedance calculation model of the mesh shielding structure of the present invention, actual verification was carried out, and the specific verification cases are as follows.

[0069] Case 1: A double-sided board is set up with an outer microstrip line stack-up structure. The wiring layer is designed with a line width of 100μm, the edge spacing of the two differential lines is 100μm, the copper thickness of the transmission cable is 50μm, the dielectric constant Dk of the dielectric layer material (FR4, epoxy resin) is 4.4, the dielectric thickness is 89μm, the conductor width a of the grid shielding layer is 1000μm, the spacing b is 1000μm, and the angles between the differential lines and the horizontal direction of the grid are 0°, 15°, 30°, 45°, 60°, and 90°, respectively. The actual measured impedance values ​​simulated by the calculation model are shown in Table 1 below.

[0070] Table 1. Comparison of differential impedance values ​​at different angles

[0071] w / um d / um t / um h / um Dk θ / ° a b Z-estimation Z measured Remark 100 100 50 89 4.4 0 1000 0 85.14 86.03 Conventional large copper surface impedance 100 100 50 89 4.4 0 1000 1000 108.56 109.98 100 100 50 89 4.4 15 1000 1000 98.84 100.81 100 100 50 89 4.4 30 1000 1000 93.39 94.05 100 100 50 89 4.4 45 1000 1000 91.64 92.15 100 100 50 89 4.4 60 1000 1000 93.38 94.19 100 100 50 89 4.4 90 1000 1000 108.52 109.56

[0072] Case 2: A double-sided board is set up with an outer microstrip line stack-up structure. The wiring layer is designed with a line width of 250μm, the edge spacing of the two differential lines is 150μm, the copper thickness of the transmission cable is 50μm, the dielectric constant Dk of the dielectric layer material (FR4, epoxy resin) is 4.4, the dielectric thickness is 89μm, the conductor width a of the mesh shielding layer is 1000μm, and the spacing b is 1000μm, 2000μm, 3000μm, and 4000μm respectively. The angle between the differential lines and the horizontal direction of the mesh is 0°. The actual measured impedance values ​​simulated by the calculation model are shown in Table 2 below.

[0073] Table 2. Influence of different mesh shielding layer spacings on differential impedance values

[0074] w / um d / um t / um h / um Dk θ / ° a b Z-estimation Z measured 250 150 50 89 4.4 0 1000 1000 71.13 73.25 250 150 50 89 4.4 0 1000 2000 94.46 96.31 250 150 50 89 4.4 0 1000 3000 113.36 112.87 250 150 50 89 4.4 0 1000 4000 127.61 125.13

[0075] The above actual verification results show that the differential impedance calculation model of the mesh shielding structure of the present invention has high calculation accuracy.

[0076] In addition, such as Figure 5 Furthermore, another embodiment of the present invention provides a differential impedance calculation system for a mesh shielding structure, preferably employing the differential impedance calculation method described above. The system includes:

[0077] The dissipation ratio calculation module is used to obtain the conductor width and spacing of the mesh shielding layer and calculate the dissipation ratio of the signal dissipation of the mesh shielding layer relative to the signal transmission of the ground layer.

[0078] The equivalent dielectric thickness calculation module is used to obtain the dielectric thickness parameters of the dielectric layer, and to equate the signal dissipation of the mesh shielding layer to the increase in dielectric thickness. The equivalent dielectric thickness is calculated based on the dissipation ratio and the dielectric thickness parameters.

[0079] The equivalent dielectric constant calculation module is used to obtain the angle between the differential line and the horizontal edge of the grid shielding layer, the dielectric constant of the dielectric layer, and to calculate the equivalent dielectric constant based on the principle of equivalent transmission time of the ground loop network.

[0080] The differential impedance calculation module is used to obtain the linewidth, copper thickness, and edge spacing between two differential lines, and calculate the differential impedance by combining the equivalent dielectric thickness, equivalent dielectric constant, and the classical differential microstrip line characteristic impedance calculation formula.

[0081] It is understood that the differential impedance calculation system of the mesh shielding structure in this embodiment takes into account that after the signal is transmitted to the mesh shielding layer, part of the signal is received and returned by the mesh shielding layer, while another part is radiated out and dissipated through the mesh holes of the mesh shielding layer, which will cause the return signal strength to change, thus affecting the accuracy of the impedance value calculation. Therefore, this invention first calculates the dissipation ratio of the signal dissipation of the mesh shielding layer relative to the signal transmission of the ground layer based on the conductor width and spacing of the mesh shielding layer. Then, it equates the signal dissipation of the mesh shielding layer to the increase in dielectric thickness of the dielectric layer, and calculates the equivalent dielectric thickness based on the dissipation ratio and dielectric thickness parameters. Then, it calculates the equivalent dielectric constant between the mesh shielding structure and the ground layer compared to the large copper shielding layer based on the principle of equivalent transmission time of the ground layer loop network. Finally, it calculates the differential impedance of the mesh shielding structure by combining the linewidth of the differential line, copper thickness, edge spacing between the two differential lines, equivalent dielectric thickness, equivalent dielectric constant, and the classical differential microstrip line characteristic impedance calculation formula of the large copper shielding layer. This invention proposes for the first time a calculation theory and model for differential impedance of a mesh shielded structure. It takes into account the influence of the dissipation effect of the mesh shielding layer on the differential impedance calculation. By equating the signal dissipation of the mesh shielding layer to an increase in dielectric thickness, and based on the principle of equivalent transmission time of the ground loop network, it calculates the equivalent dielectric constant of the mesh shielding structure compared to the large copper shielding layer, which is different from the dielectric constant of the pure dielectric between transmission lines. This greatly improves the accuracy of differential impedance calculation for the mesh shielding structure and can be well applied to the design of differential lines with mesh shielding structures, which is conducive to improving the first-pass yield of differential impedance design.

[0082] It is understood that the dissipation ratio calculation module specifically calculates the dissipation ratio based on the following formula:

[0083]

[0084] Where η represents the dissipation ratio, and a and b represent the conductor width and spacing of the mesh shielding layer, respectively.

[0085] It is understood that the equivalent dielectric thickness calculation module calculates the equivalent dielectric thickness based on the following formula:

[0086]

[0087] Where h′ represents the equivalent dielectric thickness, h represents the dielectric thickness parameter of the dielectric layer, and η represents the dissipation ratio.

[0088] It is understood that the equivalent dielectric constant calculation module calculates the equivalent dielectric constant based on the following formula:

[0089]

[0090] Where, ε′ r ε represents the equivalent dielectric constant. r θ represents the dielectric constant of the dielectric layer, and θ represents the angle between the impedance line and the horizontal edge of the grid shielding layer.

[0091] It is understood that the differential impedance calculation module calculates the differential impedance of the mesh shielding structure based on the following formula:

[0092]

[0093] Where Z2 represents the differential impedance of the mesh shielding structure, ε r ′ represents the equivalent dielectric constant, and h′ represents the equivalent dielectric thickness.

[0094] It is understood that each module in the system of this embodiment corresponds to each step in the above method embodiment. Therefore, the specific calculation principle of each module will not be repeated here, and can be referred to the above method embodiment.

[0095] In addition, another embodiment of the present invention provides an electronic device including a processor and a memory, wherein the memory stores a computer program, and the processor executes the steps of the method described above by calling the computer program stored in the memory.

[0096] In addition, another embodiment of the present invention provides a computer-readable storage medium for storing a computer program for calculating the differential impedance of a mesh shielding structure, wherein the computer program executes the steps of the method described above when run on a computer.

[0097] Common computer-readable storage media include: floppy disks, flexible disks, hard disks, magnetic tapes, any other magnetic media, CD-ROMs, any other optical media, punch cards, paper tape, any other physical media with perforated patterns, random access memory (RAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), flash erasable programmable read-only memory (FLASH-EPROM), any other memory chips or cartridges, or any other media readable by a computer. Instructions may further be transmitted or received by a transmission medium. The term transmission medium can include any tangible or intangible medium used to store, encode, or carry instructions for machine execution, and includes digital or analog communication signals or intangible media that facilitate communication of such instructions. Transmission media include coaxial cables, copper wires, and optical fibers, which contain conductors for transmitting a bus of computer data signals.

[0098] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0099] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0100] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0101] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0102] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0103] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0104] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for calculating the differential impedance of a mesh-shielded structure, wherein the impedance line structure with the mesh shielding structure includes a wiring layer, a dielectric layer, and a mesh shielding layer, wherein the wiring layer and the mesh shielding layer are respectively disposed on both sides of the dielectric layer, characterized in that, Includes the following: Obtain the conductor width and spacing of the mesh shielding layer, and calculate the ratio of signal escaping from the mesh shielding layer to signal transmission from the ground layer. The signal transmission from the ground layer refers to the signal transmission between the dielectric layer and the mesh shielding layer. Obtain the dielectric thickness parameters of the dielectric layer, and equate the signal dissipation of the mesh shielding layer to an increase in dielectric thickness. Calculate the equivalent dielectric thickness based on the dissipation ratio and dielectric thickness parameters. Obtain the angle between the differential line and the horizontal edge of the grid shielding layer, and the dielectric constant of the dielectric layer. Calculate the equivalent dielectric constant based on the principle of equivalent transmission time in the ground loop network. The differential impedance is calculated by obtaining the linewidth, copper thickness, and edge spacing between the two differential lines, and then combining the equivalent dielectric thickness, equivalent dielectric constant, and classical differential microstrip line characteristic impedance calculation formula. The differential impedance is calculated based on the following formula: ； in, The differential impedance represents the mesh shielding structure. Represents the equivalent dielectric constant. This represents the dielectric constant of the dielectric layer. The equivalent dielectric thickness is represented by w and t, which represent the linewidth and copper thickness of the differential lines, respectively, and d represents the edge spacing between the two differential lines. The process of calculating the equivalent dielectric constant based on the principle of equivalent transmission time in electric ground loop networks is as follows: In a single grid, the actual transmission time of the electrical signal is , c represents the speed of light. This represents the dielectric constant of the dielectric layer. The angle between the differential line and the horizontal edge of the grid shielding layer is represented by , and 'l' represents the length of the hypotenuse of a single grid. Based on the principle of equivalent transmission time in the electric ground loop network, assuming a transmission length of 2l, then... , Represents the equivalent dielectric constant, thus .

2. The differential impedance calculation method for the mesh shielding structure as described in claim 1, characterized in that, A curved segment is designed on one of the differential lines, and the span and height of the curved segment are smaller than the spacing of the mesh shielding layer.

3. The differential impedance calculation method for the mesh shielding structure as described in claim 1, characterized in that, The specific process for calculating the dissipation ratio is as follows: Since the electromagnetic signal lines are uniformly distributed within a single grid area, the actual signal dissipation within that single grid area is proportional to the proportion of the transmitted signal to the received signal area. ,in, Indicates the proportion of emissions. and These represent signal evaporation and signal transmission, respectively. and These represent the area of ​​the holes within a single grid region and the total area, respectively. , Let a and b represent the conductor width and spacing of the mesh shielding layer, respectively. .

4. The differential impedance calculation method for the mesh shielding structure as described in claim 3, characterized in that, The equivalent dielectric thickness is calculated based on the following formula: ； in, denoted by , where h represents the equivalent dielectric thickness and h represents the dielectric thickness parameter of the dielectric layer.

5. The differential impedance calculation method for the mesh shielding structure as described in claim 1, characterized in that, The overall width of the mesh shielding layer is infinitely wide relative to the differential lines; or, the mesh shielding layer is at least three times thicker and three times wider on each side than the differential lines in the width direction.

6. A differential impedance calculation system for a mesh shielded structure, employing the differential impedance calculation method for a mesh shielded structure as described in any one of claims 1 to 5, characterized in that, include: The dissipation ratio calculation module is used to obtain the conductor width and spacing of the mesh shielding layer and calculate the dissipation ratio of the signal dissipation of the mesh shielding layer relative to the signal transmission of the ground layer. The equivalent dielectric thickness calculation module is used to obtain the dielectric thickness parameters of the dielectric layer, and to equate the signal dissipation of the mesh shielding layer to the increase in dielectric thickness. The equivalent dielectric thickness is calculated based on the dissipation ratio and the dielectric thickness parameters. The equivalent dielectric constant calculation module is used to obtain the angle between the differential line and the horizontal edge of the grid shielding layer, the dielectric constant of the dielectric layer, and to calculate the equivalent dielectric constant based on the principle of equivalent transmission time of the ground loop network. The differential impedance calculation module is used to obtain the linewidth, copper thickness, and edge spacing between two differential lines, and calculate the differential impedance by combining the equivalent dielectric thickness, equivalent dielectric constant, and the classical differential microstrip line characteristic impedance calculation formula.

7. An electronic device, characterized in that, It includes a processor and a memory, the memory storing a computer program, the processor executing the steps of the method as described in claim 1 by calling the computer program stored in the memory.

8. A computer-readable storage medium for storing a computer program for calculating the differential impedance of a mesh-shielded structure, characterized in that, The computer program performs the steps of the method as described in claim 1 when it is run on a computer.

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