Calculation Method and System, Device, Medium for Differential Impedance of Grid Shielding Structure

Abstract

The present invention relates to a method, system, device and medium for calculating differential impedance of grid shielding structure, in which the dissipation factor is calculated based on the conductor width and spacing of the grid shielding layer, the signal dissipation and radiation farther is equivalent to the increase in dielectric thickness, the equivalent dielectric thickness is calculated, the equivalent dielectric constant between the power source and the ground is calculated based on the time equivalence principle, and the differential impedance is calculated. The present invention first proposes a calculation theory and calculation model for differential impedance of grid shielding structure, taking into account the influence of the dissipation effect of the grid shielding layer on the calculation of differential impedance, the signal dissipation of the grid shielding layer is equivalent to the increase in dielectric thickness, and the equivalent dielectric constant is calculated based on the time equivalence principle, which is different from the dielectric constant of the pure dielectric between the transmission lines, greatly improving the calculation accuracy of differential impedance of grid shielding structure, which can be well applied to the differential line design of grid shielding structure, and is helpful to improve the first pass rate of differential impedance design.

Description

Technical Field

[0001] The present invention relates to the technical field of differential impedance calculation, and particularly relates to a method and system for calculating the differential impedance of a grid shielding structure, an electronic device, and a computer-readable storage medium.

Background Art

[0002] With the popularization of personal computers, liquid crystal display technology has developed rapidly in the 21st century. With the rapid development of the communication industry, the signal transmission speed has become faster and faster, the requirements for operating frequency and transmission quality have become higher and higher, and at the same time, the types and characteristics of the light-speed transmission structures have also increased more and more. In the FPC substrate, in order to improve the flexibility of the substrate and avoid cracking of the copper surface of the large copper surface shielding layer during the bending process, usually, the shielding layer is designed in a grid shape to improve the toughness of the substrate. In the transmission of high-frequency signals, the signal layer (i.e., the wiring layer) and the ground layer (i.e., the shielding layer) transmit by the electromagnetic radiation of the high-frequency signal. According to the characteristic impedance of a typical transmission line and the measurement principle of TDR (Time Domain Reflectometry), the high-frequency signal is radiated from the signal line, and the signal is not only transmitted forward in the lead wire but also radiated to the ground. The induced signal received by the ground returns to the measurement end (the measurement end and the transmission end have a common port), and the line impedance value is calculated according to the level intensity of the transmission signal and the reflection signal. Generally, the reflectivity is ρ = V reflected / V incident is represented by, and the measured impedance is Z = Z ref *(1 + ρ) / (1 - ρ) is measured, where ρ is the signal reflectivity, V reflected is the level intensity of the reflected received signal, V incident is the level intensity of the transmission signal, and Z refis the reference resistance, usually 50 ohms. For a large metal shielding layer structure, the reflection path on the large copper surface matches the length of the transmission line, and the intensity loss of the reflected signal is mainly due to dielectric loss and conductor surface loss. In the impedance design stage, generally, the characteristic impedance of the differential microstrip line of the large copper surface shielding layer structure is calculated by the characteristic impedance calculation formula of the typical differential microstrip line. Here, the characteristic impedance calculation formula of the typical differential microstrip line is expressed by the following formula.

Equation

Equation

[0003] However, for the grid shielding structure, after the meshed grid shielding structure receives the reflected signal, it is distributed by the electromagnetic signal line and shows a uniform distribution in the local space, that is, dφ tends to be uniformly distributed in a single square area (the size of the grid of a + b dimensions, a represents the conductor width of the grid shielding layer, and b represents the distance between the conductors of the grid shielding layer). Therefore, when the signal is transmitted to the shielding layer, a part of it is received and returned by the shielding layer, and the other part is radiated and dissipated by the mesh. As a result, the return signal intensity changes, affecting the calculation of the impedance value. Therefore, the characteristic impedance calculation formula of the typical differential microstrip line is not suitable for the grid shielding structure.

Summary of the Invention

[0004] The present invention provides a method and system for calculating the differential impedance of a grid shielding structure, an electronic device, and a computer-readable storage medium, and solves the conventional technical problem that the characteristic impedance calculation formula of a typical differential microstrip line is not suitable for the grid shielding structure.

[0005] According to one aspect of the present invention, a method for calculating the differential impedance of a grid shielding structure is provided, and the method includes: obtaining the conductor width and spacing of the grid shielding layer, and calculating the dissipation rate of the signal dissipation amount of the grid shielding layer with respect to the signal transmission amount of the power ground layer; obtaining the dielectric thickness parameter of the dielectric layer, making the signal dissipation of the grid shielding layer equivalent to the increase in the dielectric thickness, and calculating the equivalent dielectric thickness based on the dissipation rate and the dielectric thickness parameter; obtaining the included angle between the differential line and the horizontal side of the grid shielding layer, and the dielectric constant of the dielectric layer, and calculating the equivalent dielectric constant based on the time equivalence principle of the network transmission of the power ground layer circuit; obtaining the width, copper thickness of the differential line, and the spacing between the edges of the two differential lines, and calculating the differential impedance based on the equivalent dielectric thickness, the equivalent dielectric constant, and the characteristic impedance calculation formula of a typical differential microstrip line.

[0006] Furthermore, the differential impedance is calculated based on the following formula.

[0007]

Equation

[0008] In the formula, Z 2 represents the differential impedance of the grid shielding structure, ε’ r represents the equivalent dielectric constant, ε r represents the dielectric constant of the dielectric layer, h’ represents the equivalent dielectric thickness, w and t represent the width and copper thickness of the differential line, and d represents the spacing between the edges of the two differential lines.

[0009] Furthermore, a curved portion is provided in one differential line, and both the span and height of the curved portion are smaller than the interval of the grid shielding layer.

[0010] Furthermore, the calculation process of the dissipation rate is specifically as follows.

[0011] Since the electromagnetic signal lines are uniformly distributed in a single grid region, the dissipation rate of the actual signal dissipation amount with respect to the signal transmission amount in a single grid region is proportional to the reception region, that is, η = φ 1 / φ 総 =S 1 / S 総 That is. In the formula, η represents the dissipation rate, φ 1 and φ 総 represent the signal dissipation amount and the signal transmission amount respectively, S 1 and S 総 represent the mesh area and the total area in a single grid region respectively, S 1 =b 2 、S 総 =(a + b) 2 That is, a and b represent the conductor width and the interval of the grid shielding layer respectively, and η = b 2 / (a + b) 2 That is.

[0012] Furthermore, the equivalent dielectric thickness is calculated based on the following formula.

[0013]

Equation

[0014] In the formula, h’ represents the equivalent dielectric thickness, and h represents the dielectric thickness parameter of the dielectric layer.

[0015] Furthermore, the process of calculating the equivalent dielectric constant based on the time equivalence principle of the network transmission of the power ground layer circuit is specifically as follows,

[0016] In a single grid, the actual transmission time of the electrical signal is represented by the following formula (Equation 5).

Number

Number

Number

Number

[0017] Furthermore, the total width of the grid shielding layer is infinite with respect to the differential line, or the grid shielding layer has a dielectric thickness that is at least three times larger and a line width that is three times larger than the differential line on at least one side in the width direction.

[0018] In addition, the present invention further provides a calculation system for the differential impedance of the grid shielding structure. The system includes a dissipation rate calculation module that acquires the conductor width and spacing of the grid shielding layer and calculates the dissipation rate of the signal dissipation amount of the grid shielding layer with respect to the signal transmission amount of the power ground layer; an equivalent dielectric thickness calculation module that acquires the dielectric thickness parameter of the dielectric layer, equates the signal dissipation of the grid shielding layer to an increase in the dielectric thickness, and calculates the equivalent dielectric thickness based on the dissipation rate and the dielectric thickness parameter; an equivalent dielectric constant calculation module that acquires the included angle between the differential line and the horizontal side of the grid shielding layer and the dielectric constant of the dielectric layer, and calculates the equivalent dielectric constant based on the time equivalence principle of the network transmission of the power ground layer circuit; A differential impedance calculation module that obtains the width of a differential line, the copper thickness, and the edge spacing between two differential lines, and calculates the differential impedance based on the equivalent dielectric thickness, the equivalent dielectric constant, and the characteristic impedance calculation formula of a typical differential microstrip line.

[0019] The present invention further provides an electronic device including a processor and a storage device. A computer program is stored in the storage device, and the processor is used to execute the steps of the foregoing method by calling the computer program stored in the storage device.

[0020] The present invention further provides a computer-readable storage medium for storing a computer program for executing the calculation of the differential impedance of a grid shielding structure. When the computer program is executed by a computer, it executes the steps of the foregoing method.

[0021] The present invention has the following effects.

[0022] In the method for calculating the differential impedance of the grid shielding structure of the present invention, when a signal is transmitted to the grid shielding layer, a part of it is received and returned by the grid shielding layer, and the other part is radiated and dissipated by the mesh of the grid shielding layer. As a result, the strength of the returned signal changes, which is considered to affect the calculation of the impedance value. Therefore, in the present invention, first, the dissipation rate of the signal dissipation amount of the grid shielding layer with respect to the signal transmission amount of the power ground layer is calculated based on the conductor width and spacing of the grid shielding layer. Next, the signal dissipation of the grid shielding layer is made equivalent to the increase in the dielectric thickness of the dielectric layer. As a result, the equivalent dielectric thickness is calculated based on the dissipation rate and the dielectric thickness parameter. Subsequently, the equivalent dielectric constant of the grid shielding structure with respect to the large copper surface shielding layer is calculated based on the time equivalent principle of the network transmission of the power ground layer circuit. This is different from the dielectric constant of the pure dielectric between the transmission lines. Finally, the differential impedance of the grid shielding structure is calculated by combining the width 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 characteristic impedance calculation formula of the typical differential microstrip line of the large copper surface shielding layer. The present invention first proposes the calculation theory and calculation model of the differential impedance of the grid shielding structure, considers the influence of the dissipation effect of the grid shielding layer on the calculation of the differential impedance, makes the signal dissipation of the grid shielding layer equivalent to the increase in the dielectric thickness, and at the same time calculates the equivalent dielectric constant of the grid shielding structure with respect to the large copper surface shielding layer based on the time equivalent principle of the network transmission of the power ground layer circuit, greatly improving the calculation accuracy of the differential impedance of the grid shielding structure, being well applicable to the differential line design of the grid shielding structure, and helping to improve the first pass rate of the differential impedance design.

[0023] Also, the differential impedance calculation system, electronic device, and computer-readable storage medium of the grid shielding structure of the present invention have the same advantages as above.

[0024] In addition to the foregoing objects, features, and advantages, the present invention has other objects, features, and advantages. Hereinafter, the present invention will be described in more detail with reference to the drawings.

Brief Description of the Drawings

[0025] The drawings forming a part of this application are used to provide a further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to interpret the present invention and are not intended to limit the present invention.

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention can be implemented in several different ways as limited and covered below.

[0028] In addition, an embodiment of the present invention provides a method for calculating the differential impedance of a grid shielding structure. As shown in FIGS. 1 and 2, an impedance line structure having a grid shielding structure specifically includes a wiring layer, a dielectric layer, and a grid shielding layer. The wiring layer and the grid shielding layer are respectively provided on both sides of the dielectric layer. Two differential lines are designed in the wiring layer, generally two single-ended microstrip lines. The grid shielding layer is an orthogonal square grid-shaped conductor. Preferably, the grid shielding layer is infinite in the width direction with respect to the differential line, or the grid shielding layer has a dielectric thickness that is at least three times greater and a line width that is three times greater than that of the differential line on at least one side in the width direction. As shown in FIG. 3, the method for calculating the differential impedance of the grid shielding structure specifically includes Step S1 of obtaining the conductor width and spacing of the grid shielding layer and calculating the dissipation rate of the signal dissipation amount of the grid shielding layer with respect to the signal transmission amount of the power supply ground layer; Step S2 of obtaining the dielectric thickness parameter of the dielectric layer, making the signal dissipation of the grid shielding layer equivalent to the increase in the dielectric thickness, and calculating the equivalent dielectric thickness based on the dissipation rate and the dielectric thickness parameter; Step S3 of obtaining the included angle between the differential line and the horizontal side of the grid shielding layer and the dielectric constant of the dielectric layer, and calculating the equivalent dielectric constant based on the time equivalent principle of the network transmission of the power supply ground layer circuit; Step S4 of obtaining the width, copper thickness of the differential line, and the spacing between the edges of the two differential lines, and calculating the differential impedance based on the equivalent dielectric thickness, the equivalent dielectric constant, and the characteristic impedance calculation formula of a typical differential microstrip line.

[0029] In addition, in the differential impedance calculation method of the grid shielding structure of this embodiment, when a signal is transmitted to the grid shielding layer, part of it is received and returned by the grid shielding layer, and the other part is radiated and dissipated by the mesh of the grid shielding layer. As a result, the intensity of the returned signal changes, which is considered to affect the calculation of the impedance value. Therefore, in the present invention, first, based on the conductor width and spacing of the grid shielding layer, the dissipation rate of the signal dissipation amount of the grid shielding layer with respect to the signal transmission amount of the power-ground layer is calculated. Next, the signal dissipation of the grid shielding layer is made equivalent to an increase in the dielectric thickness of the dielectric layer. As a result, an equivalent dielectric thickness is calculated based on the dissipation rate and the dielectric thickness parameter. Subsequently, based on the time-equivalent principle of the network transmission of the power-ground layer circuit, the equivalent dielectric constant of the grid shielding structure with respect to the power-ground layer of the large copper surface shielding layer is calculated. Finally, the differential impedance of the grid shielding structure is calculated by combining the width 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 characteristic impedance calculation formula of the typical differential microstrip line of the large copper surface shielding layer. The present invention first proposes a calculation theory and a calculation model for the differential impedance of the grid shielding structure, considers the influence of the dissipation effect of the grid shielding layer on the calculation of the differential impedance, makes the signal dissipation of the grid shielding layer equivalent to an increase in the dielectric thickness, and at the same time, based on the time-equivalent principle of the network transmission of the power-ground layer circuit, calculates the equivalent dielectric constant of the grid shielding structure with respect to the large copper surface shielding layer. This is different from the dielectric constant of the pure dielectric between the transmission lines, greatly improving the calculation accuracy of the differential impedance of the grid shielding structure, being successfully applicable to the differential line design of the grid shielding structure, and helping to improve the first-pass rate of the differential impedance design.

[0030] Note that in step S1, in the grid shielding layer, since the electromagnetic signal lines are uniformly distributed in a single grid area (i.e., the size of the square with the dimension of a + b), after the signal is transmitted to the grid shielding layer, the dissipation rate of the actual signal dissipation amount with respect to the signal transmission amount in a single grid area is proportional to the receiving area, that is, it is expressed by the following formula.

Equation

[0031]

Equation

[0032] In the above formula, η represents the dissipation rate.

[0033]

Equation

[0034]

Equation

[0035] In the formula, h’ represents the equivalent dielectric thickness, h represents the dielectric thickness parameter of the dielectric layer, and η represents the dissipation factor.

[0036] Note that in step S3, when viewed from the power ground layer circuit, the characteristic impedance transmission line is still 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 side of the right triangle of the single grid. As can be seen from the relationship between the hypotenuse and the short side of the right triangle, the signal transmission length of the grid shielding layer is l(cosθ + sinθ), where θ represents the included 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 with the transmission speed of the electrical signal in the medium, the following formula (Equation 13) is obtained.

Equation

Equation

Equation

Equation

[0037] Note that the differential impedance is also called the differential mode impedance, which includes the superposition of the characteristic impedances of two single-ended microstrip lines and the coupling attenuation due to differential mode induction between the two single-ended microstrip lines. That is, the former is the impedance to the ground, and the latter can be understood as the attenuation of the impedance of one differential line to another differential line. This can be seen from the characteristic impedance calculation formula of a typical differential microstrip line with a large copper surface shielding layer.

[0038]

Number

[0039] In the formula, Z 1 represents the differential impedance of the large copper surface shielding layer structure, ε r represents the equivalent dielectric constant of the dielectric layer, h represents the thickness of the dielectric layer (abbreviated as dielectric thickness), w and t represent the width and copper thickness of the differential line, and d represents the edge spacing between the two differential lines.

[0040] When the above formula is decomposed, it becomes as follows.

[0041]

Number

[0042] In the above formula (Equation 18), the first half (shown in Equation 19) represents the superposition of the characteristic impedances of two single-ended microstrip lines.

Number

Number

[0043] Regarding the grid shielding structure, there is signal dissipation in the mesh of the grid shielding layer. Therefore, the signal dissipation is made equivalent to an increase in the equivalent dielectric thickness. Also, when calculating the characteristic impedance of each single-ended microstrip line, it is necessary to consider the transmission of the power ground layer circuit. Thus, when calculating the superposition of the characteristic impedances of two single-ended microstrip lines, it is necessary to calculate through the equivalent dielectric thickness and the equivalent dielectric constant. The differential mode induction between two single-ended microstrip lines exists only in the power layer (wiring layer) and is not affected by the shielding layer structure. Therefore, when calculating the attenuation value of the equivalent characteristic impedance between two single-ended microstrip lines, only the influence of the equivalent dielectric thickness is considered without considering the influence of the equivalent dielectric constant. Therefore, in step S4, specifically, the differential impedance of the grid shielding structure is calculated based on the following formula (Equation 21).

[0044]

Equation

[0045] In the formula, Z 2 represents the differential impedance of the grid shielding structure, ε’ r represents the equivalent dielectric constant, and h’ represents the equivalent dielectric thickness.

[0046] Next, substituting the equivalent dielectric thickness h’ and the equivalent dielectric constant ε’ r into the above formula, it becomes as follows.

[0047]

Equation

[0048] In the formula, Z 2 represents the differential impedance of the grid shielding structure.

[0049] In addition, in order to ensure the consistency of the transmission delay between the differential mode and differential grounding and reduce the influence of the grid shielding layer, a curved portion is designed in one differential line, which is shown in FIG. 4. Moreover, both the span and height of the curved portion are smaller than the interval b of the grid shielding layer.

[0050] In addition, in order to verify the accuracy of the calculation of the differential impedance calculation model of the grid shielding structure of the present invention, actual verification is carried out, and specific verification examples are as follows.

[0051] In Example 1, a double panel is provided. According to the overlapping structure of the outer layer microstrip line, the line width of the wiring layer is set to 100 μm, the interval between the edges of the two differential lines is 100 μm, the copper thickness of the transmission line is 50 μm, the dielectric constant Dk of the dielectric layer material (FR4, epoxy resin) is 4.4, the dielectric thickness is 89 μm, the conductor width a of the grid shielding layer is 1000 μm, the interval b is 1000 μm, and the included angles between the differential line and the horizontal direction of the grid are 0°, 15°, 30°, 45°, 60°, and 90° respectively. The measured impedance values simulated by the calculation model are shown in Table 1 below.

Table 1

[0052] In Example 2, a double panel is provided. According to the overlapping structure of the outer layer microstrip line, the line width of the wiring layer is set to 250 μm, the interval between the edges of the two differential lines is 150 μm, the copper thickness of the transmission line is 50 μm, the dielectric constant Dk of the dielectric layer material (FR4, epoxy resin) is 4.4, the dielectric thickness is 89 μm, the conductor width a of the grid shielding layer is 1000 μm, the intervals b are 1000 μm, 2000 μm, 3000 μm, and 4000 μm respectively, and the included angle between the differential line and the horizontal direction of the grid is 0°. The measured impedance values simulated by the calculation model are shown in Table 2 below.

Table 2

[0053] As can be seen from the above actual verification results, the accuracy of the calculation of the differential impedance calculation model of the grid shielding structure of the present invention is very high.

[0054] In addition, as shown in FIG. 5, another embodiment of the present invention further provides a differential impedance calculation system for the grid shielding structure. Preferably, the above-described differential impedance calculation method is used. The system includes a dissipation rate calculation module for obtaining the conductor width and spacing of the grid shielding layer and calculating the dissipation rate of the signal dissipation amount of the grid shielding layer with respect to the signal transmission amount of the power ground layer; an equivalent dielectric thickness calculation module for obtaining the dielectric thickness parameter of the dielectric layer, making the signal dissipation of the grid shielding layer equivalent to the increase in the dielectric thickness, and calculating the equivalent dielectric thickness based on the dissipation rate and the dielectric thickness parameter; an equivalent dielectric constant calculation module for obtaining the included angle between the differential line and the horizontal side of the grid shielding layer and the dielectric constant of the dielectric layer, and calculating the equivalent dielectric constant based on the time equivalence principle of the network transmission of the power ground layer circuit; a differential impedance calculation module for obtaining the width, copper thickness of the differential line and the spacing between the edges of the two differential lines, and calculating the differential impedance based on the equivalent dielectric thickness, the equivalent dielectric constant and the characteristic impedance calculation formula of the typical differential microstrip line.

[0055] In the differential impedance calculation system of the grid shielding structure of this embodiment, when a signal is transmitted to the grid shielding layer, part of it is received and returned by the grid shielding layer, and the other part is radiated and dissipated by the mesh of the grid shielding layer. As a result, the strength of the return signal changes, which is considered to affect the calculation of the impedance value. Therefore, in the present invention, first, based on the conductor width and spacing of the grid shielding layer, the dissipation rate of the signal dissipation amount of the grid shielding layer with respect to the signal transmission amount of the power ground layer is calculated. Next, the signal dissipation of the grid shielding layer is made equivalent to an increase in the dielectric thickness of the dielectric layer. As a result, an equivalent dielectric thickness is calculated based on the dissipation rate and the dielectric thickness parameter. Subsequently, based on the time equivalence principle of the network transmission of the power ground layer circuit, the equivalent dielectric constant of the grid shielding structure with respect to the power ground layer of the large copper surface shielding layer is calculated. Finally, the differential impedance of the grid shielding structure is calculated by combining the width 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 characteristic impedance calculation formula of the typical differential microstrip line of the large copper surface shielding layer. The present invention proposes for the first time the calculation theory and calculation model of the differential impedance of the grid shielding structure, considers the influence of the dissipation effect of the grid shielding layer on the calculation of the differential impedance, makes the signal dissipation of the grid shielding layer equivalent to an increase in the dielectric thickness, and at the same time calculates the equivalent dielectric constant of the grid shielding structure with respect to the large copper surface shielding layer based on the time equivalence principle of the network transmission of the power ground layer circuit. This is different from the dielectric constant of the pure dielectric between the transmission lines, greatly improves the calculation accuracy of the differential impedance of the grid shielding structure, can be successfully applied to the differential line design of the grid shielding structure, and helps to improve the first-pass qualification rate of the differential impedance design.

[0056] Note that the dissipation rate calculation module specifically calculates the dissipation rate based on the following formula.

[0057]

Equation

[0058] In the formula, η represents the dissipation rate, and a and b represent the conductor width and the interval of the grid shielding layer, respectively.

[0059] Note that the equivalent dielectric thickness calculation module calculates the equivalent dielectric thickness based on the following formula.

[0060]

Equation

[0061] In the formula, h’ represents the equivalent dielectric thickness, h represents the dielectric thickness parameter of the dielectric layer, and η represents the dissipation rate.

[0062] Note that the equivalent dielectric constant calculation module calculates the equivalent dielectric constant based on the following formula.

[0063]

Equation

[0064] In the formula, ε’ r represents the equivalent dielectric constant, ε r represents the dielectric constant of the dielectric layer, and θ represents the included angle between the impedance line and the horizontal side of the grid shielding layer.

[0065] Note that the differential impedance calculation module calculates the differential impedance of the grid shielding structure based on the following formula.

[0066]

Equation

[0067] In the formula, Z 2 represents the differential impedance of the grid shielding structure, ε’ r represents the equivalent dielectric constant, and h’ represents the equivalent dielectric thickness.

[0068] Note that since each module in the system of this embodiment corresponds to each step of the above method embodiment, the specific calculation principle of each module will not be described in detail, and reference may be made to the above method embodiment.

[0069] In addition, another embodiment of the present invention further provides an electronic device including a processor and a storage device. A computer program is stored in the storage device, and the processor is used to execute the steps of the foregoing method by calling the computer program stored in the storage device.

[0070] In addition, another embodiment of the present invention further provides a computer-readable storage medium for storing a computer program for executing the calculation of the differential impedance of the grid shielding structure. When the computer program is executed by a computer, the steps of the foregoing method are executed.

[0071] Generally, the form of a computer-readable storage medium includes a floppy disk, a flexible disk, a hard disk, a magnetic tape, any other magnetic medium, a CD-ROM, any other optical medium, a punch card, a paper tape, any other physical medium with a pattern of holes, a random access memory (RAM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), a flash memory (FLASH (registered trademark)-EPROM), any other memory chip or cassette, or any other computer-readable storage medium. Instructions can be further 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, including digital or analog communication signals or intangible media that facilitate the communication of the above instructions. The transmission medium includes coaxial cables, copper wires, and optical fibers, which include the leads of a bus for transmitting computer data signals.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and changes can be made to the present invention. Modifications, equivalent replacements, improvements, etc. made within the spirit and principle scope of the present invention should be included in the protection scope of the present invention.

[0073] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Further, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to storage devices, CD-ROMs, and optical storage devices, etc.) containing computer-usable program code. The solution means in the embodiments of the present application can be realized by using various computer languages, such as the object-oriented programming language Java (registered trademark) and the interpreter-type scripting language JavaScript (registered trademark).

[0074] The present application will be described with reference to the flowcharts and / or block diagrams of the method, apparatus (system), and computer program product according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be realized by computer program instructions. These computer program instructions are provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices, so that a device is generated, and the instructions executed by the processor of the computer or other programmable data processing devices generate an apparatus for realizing the functions specified in one or more flows of the flowchart and / or one or more blocks of the block diagram.

[0075] These computer program instructions can also be stored in a computer-readable storage device that induces a computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-readable storage device produce an article of manufacture including instruction means that implement the functions specified in one or more flows of the flowchart and / or one or more blocks of the block diagram.

[0076] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus, so that a series of operational steps are performed on the computer or other programmable apparatus to produce computer-implemented processing, and thus the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in one or more flows of the flowchart and / or one or more blocks of the block diagram.

[0077] While the preferred embodiments of the present application are described, those skilled in the art can make additional changes and modifications to these embodiments if the basic inventive concept is known. Accordingly, the appended claims are intended to be construed to cover the preferred embodiments, as well as all changes and modifications within the scope of the present application.

[0078] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, these modifications and changes to the present application are intended to be included in the present application if they are within the scope of the claims of the present application and their equivalent technologies.

Claims

1. A method for calculating the differential impedance of a grid shielding structure, wherein the grid shielding structure includes a wiring layer, a dielectric layer, and a grid shielding layer. The wiring layer and the grid shielding layer are provided on both sides of the dielectric layer respectively. Two differential lines are designed in the wiring layer. In the method for calculating the differential impedance of the grid shielding structure which is an orthogonal square grid-shaped conductor, a step of obtaining the conductor width and spacing of the grid shielding layer and calculating the dissipation rate of the signal dissipation amount of the grid shielding layer with respect to the signal transmission amount of the power ground layer. The signal transmission amount of the power ground layer refers to the signal transmission amount between the power layer and the ground layer. The power layer includes the wiring layer and the dielectric layer, and the ground layer is the grid shielding layer, and the step, a step of obtaining the dielectric thickness parameter of the dielectric layer, making the signal dissipation of the grid shielding layer equivalent to the increase in the dielectric thickness, and calculating the equivalent dielectric thickness based on the dissipation rate and the dielectric thickness parameter, a step of obtaining the included angle between the differential line and the horizontal side in the width direction of the grid shielding layer and the dielectric constant of the dielectric layer, and calculating the equivalent dielectric constant based on the time equivalence principle of the network transmission of the power ground layer circuit. The power ground layer circuit is a signal transmission circuit between the power layer and the ground layer. The process of calculating the equivalent dielectric constant based on the time equivalence principle of the network transmission of the power ground layer circuit is specifically as follows, In a single grid, the actual transmission time of the electrical signal is, [Number 5] where, 【Number 6】 where, c represents the speed of light, εr represents the dielectric constant of the dielectric layer, θ represents the included angle between the differential line and the horizontal side in the width direction of the grid shielding layer, l represents the length of the hypotenuse of a single grid. Based on the time equivalence principle of the network transmission of the power ground layer circuit, assuming that the transmission length is still 2l, 【Number 7】 where, ε’r represents the equivalent dielectric constant, and as a result, 【Number 8】 where, and the step, a step of obtaining the width, copper thickness of the differential line and the spacing between the edges of the two differential lines, and calculating the differential impedance of the grid shielding structure based on the equivalent dielectric thickness, the equivalent dielectric constant and the characteristic impedance calculation formula of a typical differential microstrip line. Calculate the differential impedance of the grid shielding structure based on the following formula, 【Number 27】 In the formula, Z2 represents the differential impedance of the grid shielding structure. The differential impedance includes the superposition of the characteristic impedances of two differential lines and the coupling attenuation due to differential-mode induction between the two differential lines. ε’r represents the equivalent dielectric constant, εr represents the dielectric constant of the dielectric layer, h’ represents the equivalent dielectric thickness, w and t represent the width and copper thickness of the differential line, and d represents the edge spacing between the two differential lines. A step, A method for calculating the differential impedance of a grid shielding structure, characterized by including the above. **Claim 2** The method for calculating the differential impedance of the grid shielding structure according to claim 1, wherein a curved portion is provided on one differential line, and both the span and height of the curved portion are smaller than the spacing of the grid shielding layer. **Claim 3** The calculation process of the dissipation rate is specifically as follows. Since the electromagnetic signal lines are uniformly distributed in a single grid region, the dissipation rate of the actual signal dissipation amount with respect to the signal transmission amount in a single grid region is proportional to the reception region. That is, η = φ １ / φ 総 = S １ / S 総 where where η represents the dissipation rate, and φ １ and φ 総 represent the signal dissipation amount and the signal transmission amount respectively, S １ and S 総 represent the mesh area and the total area within a single grid region respectively, S １ = b ２ , S 総 = (a + b) ２ where a and b represent the conductor width and the interval of the grid shielding layer respectively, η = b ２ / (a + b) ２ The method for calculating the differential impedance of the grid shielding structure according to claim 1, characterized in that the above is the case. **Claim 4** Calculate the equivalent dielectric thickness based on the following formula. 【Number 28】 The method for calculating the differential impedance of the grid shielding structure according to claim 3, wherein in the formula, h’ represents the equivalent dielectric thickness, and h represents the dielectric thickness parameter of the dielectric layer. **Claim 5** The method for calculating the differential impedance of the grid shielding structure according to claim 1, wherein the grid shielding layer has a dielectric thickness at least three times larger and a line width three times larger than the differential line on at least one side in the width direction. **Claim 6** A calculation system for the differential impedance of a grid shielding structure using the method according to claim 1, a dissipation rate calculation module for obtaining the conductor width and spacing of the grid shielding layer and calculating the dissipation rate of the signal dissipation amount of the grid shielding layer with respect to the signal transmission amount of the power ground layer; an equivalent dielectric thickness calculation module for obtaining the dielectric thickness parameter of the dielectric layer, making the signal dissipation of the grid shielding layer equivalent to the increase in dielectric thickness, and calculating the equivalent dielectric thickness based on the dissipation rate and the dielectric thickness parameter; an equivalent dielectric constant calculation module for obtaining the included angle between the differential line and the horizontal side in the width direction of the grid shielding layer and the dielectric constant of the dielectric layer, and calculating the equivalent dielectric constant based on the time equivalence principle of the network transmission of the power ground layer circuit. A differential impedance calculation module for obtaining the width of a differential line, the copper thickness, and the interval between the edges of two differential lines, and calculating the differential impedance based on the equivalent dielectric thickness, the equivalent dielectric constant, and the characteristic impedance calculation formula of a typical differential microstrip line; A differential impedance calculation system for a grid shielding structure, characterized by including the above.

7. An electronic device, comprising a processor and a storage device; The storage device stores a computer program, and the processor is used to execute the steps of the method according to claim 1 by calling the computer program stored in the storage device. An electronic device characterized by this.

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