Simulation method compatible with via hole differential mode and common mode return loss
By constructing a differential signal via model in high-speed circuit board design, and using electromagnetic field simulation to optimize the rotation angle and aperture of the ground via hole, the problem of difficulty in achieving coordinated balance between differential mode and common mode return loss is solved, and signal transmission efficiency and electromagnetic compatibility are improved.
Patent Information
- Application Number
- CN202510483069.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-17
- Publication Date
- 2025-08-08
AI Technical Summary
In the existing high-speed circuit board design, the adjustment of ground via position lacks scientific quantification methods, making it difficult to achieve a coordinated balance between differential mode return loss and common mode return loss, resulting in low signal transmission efficiency and serious interference with common mode noise.
By constructing a model containing differential signal vias and ground vias on both sides, rotating around the center of adjacent differential signal vias is defined as a variable, using electromagnetic field simulation to obtain differential mode and common mode return loss at different rotation angles, setting multi-objective constraints to filter the optimal rotation angle and aperture, and determining the optimal position of ground vias.
The coordinated optimization of differential mode return loss and common mode return loss is achieved, signal transmission efficiency is improved, common mode noise interference is reduced, and electromagnetic compatibility and design accuracy are improved.
Smart Images
Figure CN120449775A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of high-speed circuit design, and in particular to a simulation method compatible with via differential mode and common mode return losses. Background Art
[0002] In the field of high-speed signal transmission, differential-mode return loss and common-mode return loss are key indicators of signal transmission quality. Differential-mode return loss reflects the extent to which some of the differential signal energy is reflected back during transmission due to factors such as line impedance mismatch. Excessive differential-mode return loss can severely reduce differential signal transmission efficiency and affect signal integrity. Common-mode return loss reflects the energy loss of the common-mode signal along the transmission path. If common-mode return loss is not ideal, common-mode noise can easily be generated and interfere with other circuits through various coupling pathways, thereby affecting the electromagnetic compatibility of the entire system.
[0003] In existing high-speed PCB designs, traditional design methods for addressing the differential-mode return loss and common-mode return loss associated with via structures have numerous shortcomings. For one thing, adjusting the position of ground vias lacks scientific quantitative methods, often relying on experience and blind trial and error. This not only consumes a significant amount of time and effort, but also fails to accurately identify the optimal ground via position that ensures both differential-mode return loss and common-mode return loss meet design requirements. This impacts differential-mode signal transmission efficiency during signal transmission, and common-mode noise interference cannot be effectively suppressed, severely restricting the stable transmission of high-speed signals in complex electromagnetic environments. Furthermore, when determining via layout, there is often a lack of comprehensive consideration of differential-mode return loss and common-mode return loss. Most optimizations are performed for either differential-mode return loss or common-mode return loss, making it difficult to achieve a coordinated balance between the two.
[0004] The above problems are worth solving. Summary of the Invention
[0005] In order to overcome the problem in the prior art that it is difficult to comprehensively consider differential mode return loss and common mode return loss when adjusting the via position and determining the via layout, and that a coordinated balance of differential mode return loss and common mode return loss cannot be achieved, the present invention provides a simulation method that is compatible with differential mode and common mode return loss of vias.
[0006] The technical solution of the present invention is as follows: A simulation method for compatible via differential mode and common mode return loss, comprising the following steps: Step 1: Construct a via structure model including a pair of differential signal vias and ground vias on both sides; Step 2: Rotate the ground vias on both sides around the center of the adjacent differential signal via, define the rotation angle as a variable, and keep the center distance between the ground via on one side and the adjacent differential signal via constant; Step 3: Obtain the differential mode return loss and common mode return loss corresponding to different rotation angle variable values through electromagnetic field simulation; Step 4: Set multi-objective constraints: differential mode return loss is less than or equal to the first target value and common mode return loss is less than or equal to the second target value; Step 5: Select the rotation angle variable value that meets the multi-objective constraint conditions as the optimal solution; Step 6: Determine the positions of the ground vias on both sides of the pair of differential signal vias based on the optimal solution.
[0007] As a preferred technical solution of the present invention, the distance between the two differential signal vias is a fixed value, and the distances between the differential signal vias and the ground vias on both sides are equal.
[0008] As a preferred technical solution of the present invention, step 2 includes the following steps: Step 201: define the center of the differential signal via on the right side as a first center point; Step 202: Set the distance between the right ground via and the right differential signal via to a constant value, rotate the right ground via counterclockwise around the first center point, and define the rotation angle as a first angle variable. Step 203: define the center of the differential signal via on the left as the second center point; Step 204: Set the distance between the left ground via and the left differential signal via to a constant value, rotate the left ground via counterclockwise around the second center point, and define the rotation angle as a second angle variable. Step 205: Set the first angle variable to be equal to the second angle variable.
[0009] As a preferred technical solution of the present invention, the first target value is -24dB.
[0010] As a preferred technical solution of the present invention, the second target value is -15dB.
[0011] As a preferred technical solution of the present invention, the range of the rotation angle variable value is 0° to 135°.
[0012] As a preferred technical solution of the present invention, the rotation angle of the optimal solution is equal to 132°, and at this time the differential mode return loss is equal to -24.75 dB, and the common mode return loss is equal to -19.13 dB.
[0013] As a preferred technical solution of the present invention, step A is also performed. If step 5 fails to screen out a rotation angle variable value that meets the conditions, the center distance between the ground vias on both sides and the differential signal vias on the corresponding sides is adjusted, and steps 2 to 5 are returned.
[0014] Furthermore, the step of adjusting the center distance between the ground vias on both sides and the differential signal vias on the corresponding sides includes: Step A1: setting the adjustment step length of the center distance between two differential signal vias; Step A2: Increase the center distance between the ground vias on both sides and the corresponding differential signal vias by one step. After the adjustment is completed, return to steps 2 to 5 to continue simulation screening. Step A3: After increasing the center distance in step A2, if no rotation angle variable value that meets the conditions can be screened out, the center distance is reduced by two steps based on the current value, and steps 2 to 5 are returned to perform simulation screening again; Step A4: Increase and decrease the step size at intervals and simulate. Each time the next step is executed, the step size is increased by one on the basis of the previous step until a rotation angle variable value that meets the conditions is screened out; if a value that meets the conditions is still not screened out, reset the multi-objective constraint conditions.
[0015] As a preferred technical solution of the present invention, the further step includes step 7. After determining the positions of the ground vias on both sides in step 6, the apertures of the ground vias on both sides are set as variable parameters. The differential-mode return loss and common-mode return loss under different ground via apertures are obtained through electromagnetic field simulation. The differential-mode return loss and common-mode return loss are compared with the differential-mode return loss and common-mode return loss obtained in step 6. The corresponding aperture value with both return losses smaller than the return loss result in step 6 is selected as the optimal ground via aperture.
[0016] The present invention according to the above scheme has the following beneficial effects: The present invention changes the angle between the ground via and the differential signal via, performs electromagnetic field simulation with the rotation angle as a variable, obtains differential-mode return loss and common-mode return loss data at different angles, and then selects the optimal rotation angle based on the multi-objective constraint condition that both the differential-mode return loss and the common-mode return loss meet the set target values, thereby determining the optimal position of the ground via next to the differential signal via. The present invention effectively solves the problem of the coupling influence of the ground via position on the two return losses through angle variable control and multi-objective optimization of the ground via and the differential signal via, avoids the design loss caused by blind adjustment, and can suppress common-mode noise interference while ensuring the differential-mode signal transmission efficiency, thereby achieving coordinated optimization of differential-mode return loss and common-mode return loss, providing an accurate quantitative design basis for the via layout of high-speed circuit boards. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 is a flow chart of the method of the present invention; Figure 2 It is a structural schematic diagram of the present invention; Figure 3 The differential mode return loss and common mode return loss curves of the optimal solution of a preferred embodiment of the present invention are shown.
[0018] In the figure, 1. Differential signal via; 2. Ground via. DETAILED DESCRIPTION
[0019] To better understand the objectives, technical solutions, and technical effects of the present invention, the present invention is further explained below with reference to the accompanying drawings and embodiments. It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. It should also be noted that the embodiments described below are intended only to illustrate the present invention and are not intended to limit the present invention.
[0020] It should be noted that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the application is typically placed when in use, or the orientation or positional relationship commonly understood by those skilled in the art, or the orientation or positional relationship in which the product of the application is typically placed when in use. This is merely for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it should not be understood as a limitation on this application. The terms "first" and "second" are used only for the convenience of description and should not be understood to indicate or imply relative importance or implicitly indicate the number of technical features. Example
[0021] like Figure 1 As shown, a simulation method for compatible via differential mode and common mode return loss includes the following steps: Step 1: Construct a via structure model including a pair of differential signal vias 1 and ground vias 2 on both sides; Step 2: Rotate the ground vias 2 on both sides around the center of the adjacent differential signal via 1, define the rotation angle as a variable, and keep the center distance between the single-side ground via 2 and the adjacent differential signal via 1 constant; Through step 2, the effect of the rotation angle on differential-mode return loss and common-mode return loss can be studied separately. By precisely controlling the variables and changing the relative positions of the ground vias, the electromagnetic properties of the via structure can be adjusted to find the ground via positions that optimize both differential-mode return loss and common-mode return loss. Step 3: Obtain the differential mode return loss and common mode return loss corresponding to different rotation angle variable values through electromagnetic field simulation; Step 4: Set multi-objective constraints: differential mode return loss is less than or equal to the first target value and common mode return loss is less than or equal to the second target value; The multi-objective optimization method in step 4 comprehensively considers the transmission characteristics of both differential and common-mode signals, avoiding the limitation of optimizing only a single indicator and achieving a coordinated balance between differential-mode return loss and common-mode return loss. Step 5: Select the rotation angle variable value that meets the multi-objective constraint conditions as the optimal solution; Step 6: Determine the positions of the ground vias 2 on both sides of the pair of differential signal vias according to the optimal solution.
[0022] The present invention accurately determines the position of the ground vias, effectively reduces differential-mode return loss, and reduces energy reflection during differential signal transmission, enabling more efficient transmission of differential signals and improving signal integrity. At the same time, by optimizing the position of the ground vias, the common-mode return loss is improved, the generation of common-mode noise is reduced, and the interference of common-mode noise on other circuits is suppressed, thereby improving the electromagnetic compatibility of the entire system.
[0023] In a preferred embodiment, the spacing between the two differential signal vias 1 is a fixed value, and the spacing between the differential signal vias 1 and the ground vias 2 on both sides is equal. This via structure model maintains a fixed spacing between the two differential signal vias and an equal spacing between the differential signal vias and the ground vias on both sides, which can make the electric field and magnetic field distribution between the vias more regular and orderly, helping to reduce mutual interference during signal transmission and reduce the differential mode return loss and common mode return loss of the initial model; and the centrally symmetrical structure can effectively suppress the generation and propagation of common mode current, reduce the radiation of common mode noise, reduce common mode return loss, and facilitate subsequent optimization work. In addition, the clear fixed and equal spacing settings provide a unified standard for circuit board via design. Designers can quickly determine the via position based on this standard when designing different projects or different parts of the same project, thereby improving design efficiency.
[0024] In a preferred embodiment, step 2 includes the following steps: Step 201: define the center of the differential signal via 1 on the right side as a first center point; Step 202: Set the distance between the right ground via 2 and the right differential signal via 1 to a constant value, rotate the right ground via 2 counterclockwise around the first center point, and define the rotation angle as a first angle variable. Step 203: define the center of the differential signal via 1 on the left as the second center point; Step 204: Set the distance between the left ground via 2 and the left differential signal via 1 to a constant value, rotate the left ground via 2 counterclockwise around the second center point, and define the rotation angle as a second angle variable. Step 205 , setting the first angle variable equal to the second angle variable; by changing the value of one variable, synchronous adjustment of the two ground vias 2 is achieved, and the electromagnetic coupling between the differential signal vias 1 on both sides is stable and balanced during the simulation process.
[0025] When the left and right ground vias rotate counterclockwise around the center of their respective adjacent differential signal vias, and the rotation angles are equal, the electromagnetic coupling on the left and right sides remains consistent, making the impedance matching of the left and right lines more stable during differential signal transmission, reducing the differential mode return loss caused by impedance mismatch.
[0026] In a specific embodiment, the differential mode return loss is less than or equal to -24dB, and the common mode return loss is less than or equal to -15dB. In this embodiment, when the differential mode return loss meets the first target, it can effectively reduce the signal attenuation and distortion caused by signal reflection, ensuring that the differential signal can be transmitted between the vias of the circuit board with high quality and low loss; when the common mode return loss reaches the second target, the energy loss of the common mode signal on the transmission path is at a low level, reducing the interference of common mode noise on other circuits through various coupling paths. The multi-objective constraint conditions prompt the design to comprehensively optimize the via structure from the two dimensions of differential mode and common mode, providing clear and quantified goals for via design, avoiding blind attempts by designers. The simultaneous satisfaction of the two target constraints can comprehensively improve the quality and stability of signal transmission, ensuring the accurate and efficient transmission of high-speed signals.
[0027] In one specific embodiment, in step 3, the rotation angle variable value ranges from 0° to 135°. This range provides a relatively comprehensive and reasonable exploration interval for studying the impact of ground via rotation on differential and common-mode return loss. At 0°, the ground via is in its initial position. Based on this, by gradually increasing the rotation angle to 135°, the ground via rotates around the differential signal via on the same side. The electromagnetic coupling between the vias changes with the rotation angle, allowing for full observation of changes in the electromagnetic performance of the via structure at different angles. This allows the angle at which both differential and common-mode return losses meet the requirements to be found, thereby optimizing both differential and common-mode return losses.
[0028] In a specific embodiment, the optimal solution has a rotation angle of 132°, and the differential mode return loss is -24.75 dB, and the common mode return loss is -19.13 dB. Figure 3 The differential mode return loss reaches -24.75 dB, meeting the design requirement of less than or equal to -24 dB. Therefore, during differential signal transmission, energy reflections caused by factors such as impedance mismatch are effectively controlled, ensuring efficient and stable differential signal transmission, reducing signal distortion and bit error rate, and improving signal transmission reliability. The common mode return loss is -19.13 dB, less than or equal to the -15 dB standard, effectively suppressing the generation and propagation of common mode noise, reducing its interference with other circuits, enhancing the electromagnetic compatibility of the entire system, and ensuring the normal coordinated operation of various circuit modules on the circuit board. Example
[0029] A simulation method for compatible via differential mode and common mode return loss, comprising the following steps: Step 1: Construct a via structure model including a pair of differential signal vias 1 and ground vias 2 on both sides; Step 2: Rotate the ground vias 2 on both sides around the center of the adjacent differential signal via 1, define the rotation angle as a variable, and keep the center distance between the single-side ground via 2 and the adjacent differential signal via 1 constant; Step 3: Obtain the differential mode return loss and common mode return loss corresponding to different rotation angle variable values through electromagnetic field simulation; Step 4: Set multi-objective constraints: differential mode return loss is less than or equal to the first target value and common mode return loss is less than or equal to the second target value; Step 5: Filter the rotation angle variable value that meets the multi-objective constraint conditions as the optimal solution, and execute step 6; If step 5 fails to filter out a rotation angle variable value that meets the conditions, adjust the center distance between the ground vias 2 on both sides and the differential signal vias 1 on the corresponding side, and return to steps 2 to 5; Step 6: Determine the positions of the ground vias 2 on both sides of the pair of differential signal vias 1 according to the optimal solution.
[0030] The step of adjusting the center distance between the ground vias 2 on both sides and the differential signal vias 1 on the corresponding side includes: Step A1: setting the adjustment step length of the center distance between the two differential signal vias 1; for example, 0.1 mm. The step length can be determined according to actual needs and accuracy requirements; Step A2: Increase the center distances between the ground vias 2 on both sides and the corresponding differential signal vias 1 by one step at a time. After the adjustment is complete, return to steps 2 to 5 to continue simulation screening. If the initial center distances between the ground vias 2 on both sides and the corresponding differential signal vias 1 are both 3 mm, increase the center distances between the ground vias 2 on both sides and the corresponding differential signal vias 1 by one step at a time, that is, from 3 mm to 3.1 mm. Then, return to steps 2 to 5, rotate the ground vias around the centers of the adjacent differential signal vias again, and obtain the differential-mode return loss and common-mode return loss corresponding to different rotation angle values through electromagnetic field simulation. Step A3: After increasing the center distance in step A2, if step 5 still fails to filter out a rotation angle variable value that meets the conditions, then reduce the center distance by two steps based on the current value, that is, restore it to a position one step smaller than the initial value, and return to step 2 for simulation screening; for example, reduce the center distance by two steps based on the current 3.1 mm, that is, reduce it to 2.9 mm, and return to steps 2 to 5 for simulation screening.
[0031] Step A4: Increase and decrease the step size at intervals and simulate. Each time the next step is executed, the step size is increased by one on the basis of the previous step until a rotation angle variable value that meets the conditions is screened out; if a value that meets the conditions is still not screened out, reset the multi-objective constraint conditions.
[0032] For example, after step A3, if the step size is reduced to 2.9mm and still no satisfying rotation angle value is found, the step size is increased by three steps from the current 2.9mm to 3.2mm, and then simulation screening is performed. If the step size is increased to 3.2mm and still no satisfying rotation angle value is found, the step size is reduced by four steps from the current 3.2mm to 2.8mm. Therefore, before a satisfying rotation angle value is found, the center distance between ground via 2 and the corresponding differential signal via 1 varies as follows: 3.0mm, 3.1mm, 2.9mm, 3.2mm, 2.8mm, 3.3mm, 2.7mm, and so on.
[0033] In Example 1, if the requirements cannot be met by relying solely on rotation angle optimization, the entire via structure may need to be redesigned, resulting in a large number of design iterations and increased costs. However, the newly added steps in this embodiment expand the optimization range of the via structure parameters by targetedly changing the center distance between the ground via 2 and the differential signal via 1; the rotation angle and center distance of the ground via 2 are used as two interrelated optimization parameters, and the multi-parameter collaborative optimization mechanism can more comprehensively explore the performance space of the via structure and find the optimal parameter combination that simultaneously meets the differential mode and common mode return loss requirements, so that designers have more opportunities to find a via layout solution that meets the design requirements, thereby increasing the probability of design success and avoiding design failure due to the limitations of a single optimization method. Example
[0034] A simulation method for compatible via differential mode and common mode return loss, characterized by comprising the following steps: Step 1: Construct a via structure model including a pair of differential signal vias 1 and ground vias 2 on both sides; Step 2: Rotate the ground vias 2 on both sides around the center of the adjacent differential signal via 1, define the rotation angle as a variable, and keep the center distance between the single-side ground via 2 and the adjacent differential signal via 1 constant; Step 3: Obtain the differential mode return loss and common mode return loss corresponding to different rotation angle variable values through electromagnetic field simulation; Step 4: Set multi-objective constraints: differential mode return loss is less than or equal to the first target value and common mode return loss is less than or equal to the second target value; Step 5: Select the rotation angle variable value that meets the multi-objective constraint conditions as the optimal solution; Step 6: Determine the positions of the ground vias 2 on both sides of the pair of differential signal vias 1 according to the optimal solution; Step 7: Set the aperture of the ground via 2 on both sides as a variable parameter, and obtain the differential mode return loss and common mode return loss of the ground via 2 at different apertures through electromagnetic field simulation. Compare them with the differential mode return loss and common mode return loss obtained in step 6, and select the corresponding aperture value with two return losses that are both smaller than the return loss result in step 6 as the optimal aperture of the ground via 2.
[0035] Based on Example 1, the optimal solution was obtained: at a rotation angle of 132°, the differential mode return loss was -24.75dB and the common mode return loss was -19.13dB. The initial aperture diameter of ground via 2 was 0.6mm, which was used as a variable parameter. Electromagnetic field simulations showed that when the aperture diameter was 0.5mm, the differential mode return loss was -25.5dB and the common mode return loss was -20.2dB; when the aperture diameter was 0.7mm, the differential mode return loss was -24.2dB and the common mode return loss was -18.8dB. Comparison revealed that the differential and common mode return losses at the 0.5mm aperture were both lower than those obtained with the basic solution in Example 1; therefore, 0.5mm was determined to be the optimal aperture diameter for ground via 2.
[0036] Based on Example 1, Example 3 introduces a new variable parameter of the aperture of ground via 2. By systematically simulating and screening different apertures of ground via 2, it is possible to accurately find the aperture value that further reduces both differential mode return loss and common mode return loss. This helps to reduce reflection and energy loss of the signal during transmission, improve signal transmission efficiency and quality, and enhance signal stability and reliability.
[0037] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0038] The above embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.
Claims
1. A simulation method compatible with differential mode and common mode return loss of vias, characterized in that: The following steps are involved: Step 1: Construct a via structure model including a pair of differential signal vias and ground vias on both sides; Step 2: Rotate the ground vias on both sides around the center of the adjacent differential signal via, define the rotation angle as a variable, and keep the center distance between the ground via on one side and the adjacent differential signal via constant; Step 3: Obtain the differential mode return loss and common mode return loss corresponding to different rotation angle variable values through electromagnetic field simulation; Step 4: Set multi-objective constraints: differential mode return loss is less than or equal to the first target value and common mode return loss is less than or equal to the second target value; Step 5: Select the rotation angle variable value that meets the multi-objective constraint conditions as the optimal solution; Step 6: Determine the positions of the ground vias on both sides of the pair of differential signal vias based on the optimal solution.
2. The simulation method for compatible via differential mode and common mode return loss according to claim 1, characterized in that: The distance between the two differential signal vias is a fixed value, and the distance between the differential signal vias and the ground vias on both sides is equal.
3. The simulation method for compatible via differential mode and common mode return loss according to claim 1, characterized in that: Step 2 includes the following steps: Step 201: define the center of the differential signal via on the right side as a first center point; Step 202: Set the distance between the right ground via and the right differential signal via to a constant value, rotate the right ground via counterclockwise around the first center point, and define the rotation angle as a first angle variable. Step 203: define the center of the differential signal via on the left as the second center point; Step 204: Set the distance between the left ground via and the left differential signal via to a constant value, rotate the left ground via counterclockwise around the second center point, and define the rotation angle as a second angle variable. Step 205: Set the first angle variable to be equal to the second angle variable.
4. The simulation method for compatible via differential mode and common mode return loss according to claim 1, characterized in that: The first target value is -24dB.
5. The simulation method for compatible via differential mode and common mode return loss according to claim 1 or 4, characterized in that: The second target value is -15dB.
6. The simulation method for compatible via differential mode and common mode return loss according to claim 1, characterized in that: The rotation angle variable value ranges from 0° to 135°.
7. The simulation method for compatible via differential mode and common mode return loss according to claim 1, characterized in that: The rotation angle of the optimal solution is equal to 132°, and at this time the differential mode return loss is equal to -24.75 dB, and the common mode return loss is equal to -19.13 dB.
8. The simulation method for compatible via differential mode and common mode return loss according to claim 1, characterized in that: Return to step A. If step 5 fails to screen out a rotation angle variable value that meets the conditions, adjust the center distance between the ground vias on both sides and the differential signal vias on the corresponding sides, and return to steps 2 to 5.
9. The simulation method for compatible via differential mode and common mode return loss according to claim 8, characterized in that: The step of adjusting the center distance between the ground vias on both sides and the differential signal vias on the corresponding sides includes: Step A1: setting the adjustment step length of the center distance between two differential signal vias; Step A2: Increase the center distance between the ground vias on both sides and the corresponding differential signal vias by one step. After the adjustment is completed, return to steps 2 to 5 to continue simulation screening. Step A3: After increasing the center distance in step A2, if no rotation angle variable value that meets the conditions can be screened out, the center distance is reduced by two steps based on the current value, and steps 2 to 5 are returned to perform simulation screening again; Step A4: Increase and decrease the step size at intervals and simulate. Each time the next step is executed, the step size is increased by one on the basis of the previous step until a rotation angle variable value that meets the conditions is screened out; if a value that meets the conditions is still not screened out, reset the multi-objective constraint conditions.
10. The simulation method for compatible via differential mode and common mode return loss according to claim 1, characterized in that: The method further includes step 7, after determining the positions of the ground vias on both sides in step 6, setting the apertures of the ground vias on both sides as variable parameters, obtaining differential-mode return loss and common-mode return loss at different ground via apertures through electromagnetic field simulation, and comparing the differential-mode return loss and common-mode return loss obtained in step 6. The aperture values corresponding to the two return losses that are both smaller than the return loss results in step 6 are selected as the optimal ground via aperture.