Simulation method for importing HFSS model into 3D layout

Abstract

The invention relates to a simulation method for importing an HFSS model in a 3D layout, and the method comprises the steps: independently opening a connector 3D model in HFSS software, and presetting two ports for the connector 3D model to form a connector HFSS engineering model; the HFSS engineering model of the connector is imported into 3D Layout simulation software; performing port alignment on the connector HFSS engineering model and the PCB layout to form a combined structure with a continuous signal transmission path; deleting redundant ports in the combined structure, and respectively arranging a signal input simulation port and a signal output simulation port at the signal input end of the connector HFSS engineering model and the wiring tail end of the PCB layout; and executing simulation. According to the method, coaxial connector and board-level joint simulation which is the same as that of HFSS software can be completed, the simulation precision reaches the precision level of the HFSS software, meanwhile, the simulation speed is superior to that of the HFSS software, and the simulation precision and the simulation efficiency are both considered.

Description

Technical Field

[0001] This invention relates to the field of circuit board design, and more specifically, to a simulation method for importing HFSS models into a 3D layout. Background Technology

[0002] Printed Circuit Boards (PCBs) serve as the core carrier for the physical support and signal transmission of electronic products. Their signal transmission performance directly determines the stability of the equipment in high-speed scenarios. Therefore, high-speed signal 3D simulation has become an indispensable key step in the PCB design process. Currently, the two mainstream 3D simulation software programs in the industry are HFSS and 3D Layout. They differ significantly in their technical positioning and functional characteristics. 3D Layout has distinct PCB-specific adaptation characteristics—it is optimized for PCB and package design scenarios, can directly import PCB files and automatically complete the processing of PCB-specific elements such as stack-up structures and vias, eliminating the need for manual modeling by engineers and significantly lowering the operational threshold for PCB layout simulation. At the same time, 3D Layout supports the import of parametric variables and S-parameter models, which can effectively reduce repetitive modeling work. Furthermore, its integrated interface simplifies the port setting process. For example, for PCB pads, traces, and other structures, there is no need for complex manual configurations like in other software. Therefore, 3D Layout has a significant efficiency advantage in high-frequency circuit board simulation.

[0003] However, the advantages of 3D Layout are limited to the simulation of the PCB layout itself. It has a significant limitation in the co-simulation of complex 3D structures—it cannot directly import and use complex 3D models such as 3D coaxial connectors used for signal interconnection between the PCB and external devices. In actual engineering, signal interaction between the PCB and external devices often relies on coaxial connectors. Co-simulation of the coaxial connector and PCB traces is necessary to accurately reflect the real signal transmission characteristics. However, 3D Layout can only import the PCB layout and cannot integrate the 3D coaxial connector model into the simulation system. This results in the simulation scope only covering the pad locations on the PCB layout. Specifically, engineers can only create simulation ports at the corresponding connector pads on the PCB, plus ports at the ends of the PCB traces, to conduct the simulation.

[0004] HFSS, as a general-purpose 3D electromagnetic field simulation software, can manually import 3D coaxial connector models to achieve high-precision simulation results in co-simulation. However, HFSS requires manual definition of geometry and manual configuration of port parameters, making the modeling process complex. Moreover, for co-simulation scenarios involving PCB boards, the computational load is enormous, and the simulation speed is far lower than that of 3D Layout.

[0005] The misalignment of the aforementioned software functions presents simulation engineers with a dilemma: choosing 3D Layout for simulation efficiency results in an incomplete simulation of the signal transmission path due to the lack of a 3D model of the coaxial connector, leading to significant discrepancies between simulation results and actual conditions. For example, in impedance simulations at the same location, 3D Layout's simulation result with a port built at the pad is 48.5 ohms, while HFSS's simulation result with the coaxial connector is 47 ohms, a significant difference. Choosing HFSS to ensure simulation accuracy, however, extends the development cycle due to its complex modeling and slow simulation speed.

[0006] Therefore, how to solve the problems of insufficient simulation accuracy of 3D Layout software, low simulation efficiency of HFSS software, and the difficulty in balancing efficiency and accuracy in existing simulation methods has become a technical bottleneck that the industry urgently needs to overcome. Summary of the Invention

[0007] To overcome the problems of existing technologies where 3D layouts cannot be co-simulated using connector 3D models, and individual simulations lack accuracy, while existing HFSS simulations are slow, making it difficult to balance efficiency and accuracy, this invention provides a simulation method for importing HFSS models into 3D layouts.

[0008] The technical solution of this invention is as follows: A simulation method for importing HFSS models into a 3D layout, characterized by the following steps: Open the connector 3D model separately in HFSS software, and pre-set two ports for co-simulation with the PCB layout to form a connector HFSS engineering model with port attributes. Import the connector HFSS engineering model into the 3D Layout simulation software with the PCB layout already loaded; In the 3D Layout simulation software, the connector HFSS engineering model and the PCB layout are aligned at the ports, so that the connector HFSS engineering model and the PCB layout form a combined structure with a continuous signal transmission path; Remove redundant ports within the composite structure; In terms of the combined structure, signal input and output simulation ports are set at the signal input end of the connector HFSS engineering model and the trace end of the PCB layout, respectively; Based on the simulation port, perform high-speed signal 3D simulation of the PCB in 3D layout simulation software.

[0009] Optionally, the connector 3D model is a coaxial connector 3D model used for signal interconnection between the PCB board and external devices.

[0010] As a preferred embodiment of the present invention, the specific steps for setting two ports in the 3D model of the connector include: A first port is provided at the signal input end of the connector 3D model, and a second port is provided at the signal output end of the connector 3D model. The first port and the second port are distributed along the signal transmission direction of the connector 3D model.

[0011] As a preferred embodiment of the present invention, the specific steps for importing the connector HFSS engineering model into 3D layout simulation software with a loaded PCB layout include: In 3D layout simulation software, a first project file containing a PCB layout is created. The PCB layout has pad structures for signal transmission, and the pad structures are provided with pad ports. Export a second project file containing the connector HFSS engineering model from the HFSS software. Import the second project file into the 3D Layout simulation software and combine it with the first project file, so that the connector HFSS engineering model and PCB layout are displayed simultaneously in the operating space.

[0012] Furthermore, the specific steps for aligning the connector's HFSS engineering model with the PCB layout include: Align the second port of the connector's HFSS engineering model with the pad port of the PCB layout to form a continuous signal transmission path.

[0013] Furthermore, the specific steps for removing redundant ports within the composite structure include: After aligning the second port of the connector HFSS engineering model with the pad port of the PCB layout, delete the second port of the connector HFSS engineering model so that the second port no longer participates in the simulation as a simulation port, and only retain the first port of the connector HFSS engineering model as the input port to be configured for the combined structure.

[0014] As a preferred embodiment of the present invention, the specific steps of setting signal input and output simulation ports at the signal input end of the connector HFSS engineering model and the trace end of the PCB layout include: In the 3D Layout simulation software, select the edge of the first port of the connector HFSS engineering model to construct the input simulation port for signal input; In 3D layout simulation software, select the edge of the PCB layout away from the end of the trace structure to construct the output simulation port for signal output.

[0015] Furthermore, the specific steps for selecting the first port or the edge of the trace end include: In 3D Layout simulation software, the edge selection function is triggered to select the edge of the target, and then the port creation function is triggered to create a port, thus completing the input simulation port and the output simulation port; when creating the simulation port, the port parameters are configured, and the port parameters include at least one of port impedance, port type, and port direction.

[0016] As a preferred embodiment of the present invention, a verification step is further included, the verification step comprising: The HFSS software was used to simulate the combined model, which included the 3D model of the connector and the 3D model of the PCB board. The simulation results from the 3D Layout simulation software were compared with those from the HFSS software to verify consistency.

[0017] Furthermore, the simulation results include at least one of TDR impedance, insertion loss, and return loss, and the verification results that meet the requirements are: The difference in TDR impedance results should not exceed 0.5Ω; The difference in insertion loss results should not exceed 0.05 dB; The difference in return loss results should not exceed 2.5 dB.

[0018] According to the above-described solution, the beneficial effects of this invention are as follows: This invention solves the problem that 3D layout simulation software cannot directly use connector 3D models for co-simulation by pre-setting co-simulation ports in the connector 3D model in HFSS software to form an engineering model. After importing the connector HFSS engineering model into the 3D layout simulation software, port alignment, deletion of redundant ports, and setting of simulation ports are performed to achieve a complete match between the 3D layout simulation scene and the actual path of signal input from the connector and transmission through PCB traces in the actual device. This allows the simulation to accurately reflect the signal transmission characteristics at the connector-PCB interface, effectively making up for the lack of accuracy when traditional 3D layout simulates PCB layouts alone. It also retains the convenience of simplified port settings in the integrated interface of 3D layout and fully leverages the inherent advantage of high-speed 3D layout simulation, ultimately achieving synergistic optimization of efficiency and accuracy in high-speed signal simulation. Attached Figure Description

[0019] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a comparison chart of the TDR impedance results of the method of this invention and the traditional HFSS simulation method; Figure 3 This is a comparison chart of the insertion loss results between the method of this invention and the traditional HFSS simulation method; Figure 4 This is a comparison chart of the return loss results between the method of this invention and the traditional HFSS simulation method.

[0020] In the diagram, a- The method of this invention; b- Traditional HFSS simulation method. Detailed Implementation

[0021] To better understand the purpose, technical solution, and technical effects of this invention, the invention will be further explained and described below in conjunction with the accompanying drawings and embodiments. It should be noted that similar reference numerals and letters in the following drawings indicate similar items; therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. It is also stated that the embodiments described below are only for explaining this invention and are not intended to limit this invention.

[0022] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features.

[0023] like Figure 1 As shown, a simulation method for importing an HFSS model into a 3D layout includes the following steps: Step 1: Open the connector 3D model separately in HFSS software, and pre-set two ports for co-simulation with the PCB layout to form a connector HFSS engineering model with port attributes. Step 2: Import the connector HFSS engineering model into the 3D Layout simulation software with the PCB layout already loaded; Step 3: In the 3D Layout simulation software, align the connector HFSS engineering model with the PCB layout to form a combined structure with a continuous signal transmission path. Step 4: Delete redundant ports within the combined structure; Step 5: On the combined structure, set signal input and output simulation ports at the signal input end of the connector HFSS engineering model and the end of the trace on the PCB layout, respectively; Step 6: Based on the simulation port, perform 3D simulation of high-speed signals on the PCB in the 3D Layout simulation software.

[0024] In this embodiment, the connector 3D model is a coaxial connector 3D model used for signal interconnection between the PCB board and external devices. Step 1 is executed, setting a first port at the signal input end (i.e., the top surface of the coaxial connector) of the coaxial connector 3D model as the basis for subsequent simulation signal input, and setting a second port at the signal output end (i.e., the bottom surface of the coaxial connector) of the coaxial connector 3D model for docking with the PCB board pads. The two ports are distributed along the signal transmission direction from top to bottom of the coaxial connector 3D model; this is saved as an HFSS project file containing port attributes and electromagnetic parameters. This step solves the pain point of existing 3D Layout simulation methods that cannot directly import coaxial connector models (such as STEP format) and cannot participate in simulation. By first using HFSS to assign port definitions and electromagnetic attributes to the connector 3D model, the model is transformed from a pure geometric structure into a simulable engineering model, successfully imported into 3D Layout to achieve co-simulation with the PCB layout.

[0025] Step 2, importing the connector HFSS engineering model into the 3D layout simulation software with the loaded PCB layout, includes the following steps: Create a new first project file in the 3D Layout simulation software, import or create a PCB layout. The PCB layout represents PCB board information, including pad structures with pin adapters designed to match coaxial connectors, and the pad structures have pad ports. Export a second project file from the HFSS software. This second project file contains the connector HFSS project model from the previous steps. Import this second project file into the 3D Layout simulation software and drag it into the first project file, so that the connector HFSS project model and the PCB layout are displayed simultaneously in the workspace. At this point, the PCB layout model is displayed in the upper right corner of the workspace, and the dragged-in connector HFSS project model is displayed in the lower left corner. This step 2 achieves cross-software model fusion while retaining the advantage of the original 3D Layout automatically recognizing PCB stack-ups and vias, without requiring additional PCB parameter configuration.

[0026] Step 3 aligns the connector HFSS engineering model with the PCB layout, creating a combined structure with a continuous signal transmission path. Specifically, the connector HFSS engineering model is selected and positioned to align its second port with the pad port on the PCB layout. This essentially aligns the pins of the coaxial connector with the pads on the PCB, forming a continuous signal transmission path: "connector top → bottom pin → PCB pad → PCB trace". Existing 3D layout simulations can only simulate the partial path from the PCB pad to the trace, not the path from the connector to the pad. Step 3 ensures the simulated path perfectly matches the actual path, improving subsequent simulation accuracy.

[0027] Perform step 4 to remove redundant ports within the composite structure. The specific steps include: After alignment, select the second port of the connector HFSS engineering model and delete it. This prevents the second port from participating in the simulation, leaving only the first port of the connector HFSS engineering model as the input port to be configured for the combined structure. This step 4 eliminates invalid internal ports, preventing them from interfering with the simulation calculations and causing distortion in the electromagnetic field distribution at the coaxial connector and pad interface, thus introducing accuracy errors.

[0028] Step 5 establishes the input and output simulation ports of the combined structure. Specifically, in the 3D Layout simulation software, select the edge of the first port of the connector HFSS engineering model, trigger the port creation command, and construct the input simulation port for signal input on the top surface of the connector HFSS engineering model. In the 3D Layout simulation software, select the edge of the trace end away from the pad structure on the PCB layout, trigger the port creation command, and construct the output simulation port for signal output at the end of the trace away from the connector. This step 5 utilizes the integrated advantage of the 3D Layout simulation software's "select edge → one-click port creation" to quickly complete the setting of the two ports, ensuring that the port attributes are consistent with the real scene.

[0029] The specific steps for selecting the first port or the edge of the trace end include: In 3D Layout simulation software, select the object in the parameter tree on the left side of the operation interface, right-click the object to trigger the edge selection function to select the edge of the target, and then trigger the port creation function to create the port, thus completing the input simulation port and output simulation port; and configure the port parameters when creating the simulation port, including at least one of the following: port impedance, port type, and port direction.

[0030] Finally, execute step 6 to start the high-speed signal 3D simulation in 3D Layout. The simulation results include at least one of TDR impedance, insertion loss, and return loss.

[0031] In summary, this invention solves the problem that 3D layout simulation software cannot directly use connector 3D models for co-simulation by pre-setting co-simulation ports in the connector 3D model in HFSS software to form an engineering model. After importing the connector HFSS engineering model into the 3D layout simulation software, port alignment, deletion of redundant ports, and setting simulation ports are performed to achieve a complete match between the 3D layout simulation scene and the actual path of signal input from the connector and transmission through PCB traces in the actual device. This allows the simulation to accurately reflect the signal transmission characteristics at the connector-PCB interface, effectively compensating for the insufficient accuracy of traditional 3D layout when simulating PCB layout alone. It also retains the convenience of simplified port settings using the integrated interface of 3D layout and fully leverages the inherent advantage of high-speed 3D layout simulation, ultimately achieving synergistic optimization of efficiency and accuracy in high-speed signal simulation.

[0032] Additionally, this invention includes a verification step, which comprises: A joint 3D model of a coaxial connector and a PCB board of the same specifications was created using HFSS software. Simulations were performed in the same frequency band to obtain the TDR impedance, insertion loss, and return loss. The preset verification results are as follows: The difference in TDR impedance results should not exceed 0.5Ω; The difference in insertion loss results should not exceed 0.05 dB; The difference in return loss results should not exceed 2.5 dB.

[0033] like Figures 2 to 4 As shown, in the verification step of a specific embodiment, compared with the traditional HFSS simulation method, the TDR impedance result of the present invention differs by 0.4Ω at 68ps, the maximum difference in insertion loss result is less than 0.04dB, and the difference in return loss result at 9.8GHz is 2.5dB. This indicates that the simulation accuracy of the present invention is comparable to that of the traditional HFSS simulation, and it retains the calculation speed of 3D Layout software, thus balancing simulation accuracy and simulation efficiency.

[0034] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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.

[0035] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A simulation method for importing HFSS models into a 3D layout, characterized in that, Includes the following steps: Open the connector 3D model separately in HFSS software, and pre-set two ports for co-simulation with the PCB layout to form a connector HFSS engineering model with port attributes. Import the connector HFSS engineering model into the 3D Layout simulation software with the PCB layout already loaded; The connector HFSS engineering model and the PCB layout are aligned at the ports to form a combined structure with a continuous signal transmission path. Remove redundant ports inside the combined structure, and set signal input and output simulation ports at the signal input end of the connector HFSS engineering model and the trace end of the PCB layout, respectively; Perform high-speed 3D simulation of PCB signals based on the simulation port.

2. The simulation method for importing an HFSS model into a 3D layout according to claim 1, characterized in that, The connector 3D model is a coaxial connector 3D model used for signal interconnection between the PCB board and external devices.

3. The simulation method for importing an HFSS model into a 3D layout according to claim 1 or 2, characterized in that, The specific steps for setting up two ports on a connector 3D model include: A first port is provided at the signal input end of the connector 3D model, and a second port is provided at the signal output end of the connector 3D model. The first port and the second port are distributed along the signal transmission direction of the connector 3D model.

4. The simulation method for importing an HFSS model into a 3D layout according to claim 3, characterized in that, The specific steps for importing the connector HFSS engineering model into 3D layout simulation software with an already loaded PCB layout include: In 3D layout simulation software, a first project file containing a PCB layout is created. The PCB layout has pad structures for signal transmission, and the pad structures are provided with pad ports. Export a second project file containing the connector HFSS engineering model from the HFSS software. Import the second project file into the 3D Layout simulation software and combine it with the first project file, so that the connector HFSS engineering model and PCB layout are displayed simultaneously in the operating space.

5. The simulation method for importing an HFSS model into a 3D layout according to claim 4, characterized in that, The specific steps for aligning the connector's HFSS engineering model with the PCB layout include: Align the second port of the connector's HFSS engineering model with the pad port of the PCB layout to form a continuous signal transmission path.

6. The simulation method for importing an HFSS model into a 3D layout according to claim 5, characterized in that, The specific steps for removing redundant ports within the composite structure include: After aligning the second port of the connector HFSS engineering model with the pad port of the PCB layout, delete the second port of the connector HFSS engineering model so that the second port no longer participates in the simulation as a simulation port, and only retain the first port of the connector HFSS engineering model as the input port to be configured for the combined structure.

7. The simulation method for importing an HFSS model into a 3D layout according to claim 3, characterized in that, The specific steps for setting signal input and output simulation ports at the signal input end of the connector HFSS engineering model and at the end of the traces on the PCB layout include: In the 3D Layout simulation software, select the edge of the first port of the connector HFSS engineering model to construct the input simulation port for signal input; In 3D layout simulation software, select the edge of the PCB layout away from the end of the trace structure to construct the output simulation port for signal output.

8. The simulation method for importing an HFSS model into a 3D layout according to claim 7, characterized in that, The specific steps for selecting the first port or the edge of the trace end include: In 3D Layout simulation software, the edge selection function is triggered to select the edge of the target, and then the port creation function is triggered to create a port, thus completing the input simulation port and the output simulation port; when creating the simulation port, the port parameters are configured, and the port parameters include at least one of port impedance, port type, and port direction.

9. The simulation method for importing an HFSS model into a 3D layout according to claim 1, characterized in that, It also includes a verification step, which includes: The HFSS software was used to simulate the combined model, which included the 3D model of the connector and the 3D model of the PCB board. The simulation results from the 3D Layout simulation software were compared with those from the HFSS software to verify consistency.

10. The simulation method for importing an HFSS model into a 3D layout according to claim 9, characterized in that, The simulation results include at least one of TDR impedance, insertion loss, and return loss, and the verification results that meet the requirements are: The difference in TDR impedance results should not exceed 0.5Ω; The difference in insertion loss results should not exceed 0.05 dB; The difference in return loss results should not exceed 2.5 dB.

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