Radio frequency dummy load multi-physical field simulation method

Abstract

The invention discloses a radio frequency dummy load multi-physical field simulation method, which comprises the following steps of S1, performing electromagnetic characteristic analysis on a radio frequency dummy load wave-absorbing structure, and calculating power loss distribution; s2, importing the power loss distribution into thermal simulation software, performing thermal simulation, and calculating steady-state temperature distribution of the radio frequency dummy load wave-absorbing structure in the oil medium; s3, taking the temperature distribution obtained by thermal simulation as a load, performing structural analysis on the radio frequency dummy load wave-absorbing structure, and obtaining thermal deformation of each part; and S4, introducing the radio frequency dummy load wave-absorbing structure after thermal deformation, updating the material characteristics, performing simulation, and finally obtaining the electromagnetic performance of the radio frequency dummy load wave-absorbing structure influenced by the temperature. By comprehensively considering the interaction of a plurality of physical fields such as an electromagnetic field, a thermal field and a mechanical field, the performance of the radio frequency dummy load in an actual working environment can be simulated more accurately, and potential design problems can be found, so that the design accuracy and reliability are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of radio frequency simulation, and in particular to a radio frequency dummy load multi-physical field simulation method. Background Art

[0002] RF loads are widely used in power electronics, wireless communications, satellite communications, radar, medical equipment and other fields to perform impedance matching on unused spare channels and test ports for RF testing and absorbing port RF energy to ensure the stability and reliability of the equipment.

[0003] As an important testing tool, RF dummy load plays an indispensable role in the design, development and maintenance of electronic equipment. By using a dummy load, the load conditions of electronic equipment can be simulated without a real load, so as to test the output capacity and stability of the power supply or other electronic equipment. By connecting a dummy load, the real load condition can be simulated, so that the switching power supply can work stably under no-load or light-load conditions, avoiding excessive output voltage, thereby protecting the power supply and other circuit components from damage. The use of RF dummy loads can also optimize the design and maintenance process. By testing with a dummy load, potential problems can be discovered and solved in a timely manner, and failures in actual use can be avoided, thereby improving the reliability and service life of the equipment.

[0004] The design of traditional RF dummy loads mainly relies on empirical formulas and experimental tests, which have many limitations. First, empirical formulas are often based on simplified physical models, which are difficult to accurately reflect the actual performance of RF dummy loads in complex multi-physical field environments. Second, although experimental tests can provide relatively accurate data, they are costly, time-consuming, and difficult to cover all possible working conditions and failure modes. Therefore, there is an urgent need for a more efficient and accurate design optimization method to meet the growing performance requirements of RF dummy loads. Summary of the invention

[0005] The present invention overcomes the deficiencies of the prior art and provides a radio frequency dummy load multi-physical field simulation method.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a radio frequency dummy load multi-physical field simulation method, comprising the following steps:

[0007] S1. Analyze the electromagnetic characteristics of the RF dummy load absorbing structure through simulation software, and calculate the power loss distribution of each part in the post-processing stage;

[0008] S2. Import the power loss distribution obtained by electromagnetic characteristic analysis into thermal simulation software, set the corresponding background temperature, and perform thermal simulation to calculate the steady-state temperature distribution of the RF dummy load absorbing structure in the oil medium;

[0009] S3. The temperature distribution obtained by thermal simulation is used as a load and applied to the thermal-mechanical coupling analysis to perform a structural analysis of the RF dummy load absorbing structure to obtain the thermal deformation of each part;

[0010] S4. Re-import the RF dummy load absorbing structure after thermal deformation, update the material properties of the RF dummy load absorbing structure, import the thermal deformation caused by temperature and the nonlinear change of material parameters with temperature for simulation, and finally obtain the electromagnetic performance of the RF dummy load absorbing structure affected by temperature.

[0011] In a preferred embodiment of the present invention, the step S1 includes the following sub-steps:

[0012] S11. Create a three-dimensional geometric model of the RF dummy load in the simulation software, including the metal parts, dielectric materials and air gap involved;

[0013] S12. Assign electromagnetic material properties to different materials in the model, including the dielectric constant and conductivity involved;

[0014] S13, select a high-frequency electromagnetic field solver, set the transmission signal operating frequency and signal power when the external temperature does not change, perform simulation, and calculate the electric field, current and loss distribution of the RF dummy load absorbing structure.

[0015] In a preferred embodiment of the present invention, in step S11, the simulation software is the commercial simulation software CST, and is CST Microwave Studio.

[0016] In a preferred embodiment of the present invention, in the step S13, the relationship between the electric field and the electric potential is calculated: E=-▽V; wherein E is the electric field and V is the electric potential;

[0017] Calculate the relationship between current density and electric field: J = -σE + J e ; where J is the current density, σ is the conductivity, J e is the current density generated outside the material;

[0018] Calculate the electromagnetic volume loss density: Among them, Q e is the electromagnetic volume loss density.

[0019] In a preferred embodiment of the present invention, in step S2, the thermal simulation software is an electromagnetic-thermal collaborative simulation studio.

[0020] In a preferred embodiment of the present invention, in step S2, the background temperature is 50° C.-200° C.; and the boundary condition adopted by the thermal simulation is an open boundary.

[0021] In a preferred embodiment of the present invention, in step S2, the calculation of the steady-state temperature distribution is: ρC p u·▽T+▽·q=Q e +Q ted ; where ρ is the resistivity, C p is the specific heat capacity, u is the displacement, ▽T is the temperature gradient, q is the heat flux, Q ted is the thermoelastic damping;

[0022] Resistivity Where R is the resistance, S is the cross-sectional area, and d is the length;

[0023] Heat flux q = -k▽T, where k is thermal conductivity;

[0024] Thermoelastic Damping Where α is the coefficient of thermal expansion, T is the temperature, is the rate of change of the strain tensor with time.

[0025] In a preferred embodiment of the present invention, in step S3, the strain tensor of the thermal deformation is calculated as: Where u is the displacement and T is the temperature;

[0026] The calculation of solid heat transfer is: ▽·S+F v = 0, where S is the thermal strain, F v It is the volume force;

[0027] The elastic stress is calculated as: S el =C:ε el , where S el is the elastic stress, C is the elastic modulus, ε el is the elastic strain;

[0028] Elastic modulus C = C(E,υ), where E is the electric field and υ is the strain.

[0029] In a preferred embodiment of the present invention, the step S4 includes the following sub-steps:

[0030] S41, re-importing the radio frequency dummy load absorbing structure after thermal deformation obtained in step S3 into the simulation software in step S1, and updating the material properties of the radio frequency dummy load absorbing structure, including the dielectric constant and conductivity involved;

[0031] S42. According to the simulation process of electromagnetic-thermal-mechanical multi-physics fields in the simulation software, the thermal deformation caused by temperature and the nonlinear changes of material parameters with temperature are imported for simulation, and the electromagnetic properties affected by temperature are analyzed and visualized.

[0032] In a preferred embodiment of the present invention, in the step S41, the dielectric constant ε th The calculation of ε is: th =β(TT ref ), where β is the temperature coefficient, T ref is the reference temperature;

[0033] The conductivity σ is calculated as: where ρo is the reference resistivity.

[0034] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0035] (1) The present invention provides a multi-physical field simulation method for a radio frequency dummy load. By comprehensively considering the interaction of multiple physical fields such as electromagnetic fields, thermal fields and mechanical fields, the performance of the radio frequency dummy load in an actual working environment can be more accurately simulated, which helps to discover potential design problems such as overheating, deformation or stress concentration, thereby improving the accuracy and reliability of the design. Through simulation analysis, the heat sink structure of the radio frequency dummy load can be optimized to dissipate heat more effectively, reduce the internal temperature, and improve the stability and service life of the radio frequency dummy load.

[0036] (2) In the present invention, the multi-physics field simulation method can be used to quickly iterate the design on the computer, and the performance of different design solutions can be evaluated without making physical prototypes. This greatly shortens the product development cycle and accelerates the time to market. Through simulation analysis, potential problems can be discovered and solved at an early stage, reducing the cost of later experiments and tests. At the same time, simulation can also provide guidance for experiments, reducing the number of experiments and the waste of experimental resources.

[0037] (3) In this invention, the cross-integration theory and method of electronic science, electromagnetic science, information technology, reliability physics, functional safety and mathematical statistics are used to propose the "triangle" robustness concept of reliability and functional safety of RF electronic systems. The evolution law of electromagnetic characteristics in a multi-physical field environment, the mechanism of action of environmental factors and the defense control of behavioral risks, as well as the mutual influence and correlation among the three are studied, and a typical electromagnetic-thermal coupling mechanism of RF electronic systems is given, which can be applied to similar systems.

[0038] (4) In the present invention, by adopting a design method of bidirectional coupling and interaction of multiple physical fields, the coupling relationship between the electromagnetic field, thermal field, and stress field is comprehensively analyzed, the electrical performance is solved by high-frequency electromagnetic simulation software, and the thermodynamic simulation is performed on it using finite element analysis software. The deformation results after analysis and calculation are returned to the high-frequency electromagnetic simulation software, and finally the design of the absorbing structure of the RF dummy load is completed, which can achieve an absorbing frequency band of 6 GHz and a power of 2 kW, thereby completing the intelligent design of the RF dummy load. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0040] Figure 1 It is a flow chart of a multi-physics field simulation method of a radio frequency dummy load according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0043] like Figure 1 As shown, a multi-physics field simulation method for a radio frequency dummy load comprises the following steps:

[0044] S1. Analyze the electromagnetic characteristics of the RF dummy load absorbing structure through simulation software, and calculate the power loss distribution of each part in the post-processing stage;

[0045] S2. Import the power loss distribution obtained by electromagnetic characteristic analysis into thermal simulation software, set the corresponding background temperature, and perform thermal simulation to calculate the steady-state temperature distribution of the RF dummy load absorbing structure in the oil medium;

[0046] S3. The temperature distribution obtained by thermal simulation is used as a load and applied to the thermal-mechanical coupling analysis to perform a structural analysis of the RF dummy load absorbing structure to obtain the thermal deformation of each part;

[0047] S4. Re-import the RF dummy load absorbing structure after thermal deformation, update the material properties of the RF dummy load absorbing structure, import the thermal deformation caused by temperature and the nonlinear change of material parameters with temperature for simulation, and finally obtain the electromagnetic performance of the RF dummy load absorbing structure affected by temperature.

[0048] It should be noted that by comprehensively considering the interaction of multiple physical fields such as electromagnetic fields, thermal fields and mechanical fields, the performance of the RF dummy load in the actual working environment can be simulated more accurately, which helps to discover potential design problems such as overheating, deformation or stress concentration, thereby improving the accuracy and reliability of the design. Through simulation analysis, the heat sink structure of the RF dummy load can be optimized to dissipate heat more effectively, reduce the internal temperature, and improve the stability and service life of the RF dummy load.

[0049] In some specific implementations, the step S1 includes the following sub-steps:

[0050] S11. Create a three-dimensional geometric model of the RF dummy load in the simulation software, including the metal parts, dielectric materials and air gap involved;

[0051] S12. Assign electromagnetic material properties to different materials in the model, including the dielectric constant and conductivity involved;

[0052] S13, select a high-frequency electromagnetic field solver, set the transmission signal operating frequency and signal power when the external temperature does not change, perform simulation, and calculate the electric field, current and loss distribution of the RF dummy load absorbing structure.

[0053] In step S11, the simulation software is preferably a commercial simulation software CST, and is CST Microwave Studio; CST specifically refers to CST Studio Suite, a professional-grade software tool widely used in electromagnetic field simulation. CSTStudio Suite can simulate various electromagnetic phenomena, including microwave transmission, radio frequency and millimeter wave technology, optical systems and electronic devices, and supports a simple and easy-to-use operation mode through its user-friendly graphical interface, so that simulation analysis can be quickly performed.

[0054] In step S13, the relationship between the electric field and the electric potential is calculated: E=-▽V; where E is the electric field and V is the electric potential; it means that the electric field is the negative gradient of the electric potential, which is used to describe how the electric field points from a high-value area of ​​the electric potential to a low-value area;

[0055] Calculate the relationship between current density and electric field: J = -σE + J e ; where J is the current density, σ is the conductivity, J e It is the current density generated outside the material; it means that the current density is composed of the product of conductivity and electric field and the current density generated externally, and is used to consider the current flow inside the material and the influence of external current sources;

[0056] Calculate the electromagnetic volume loss density: Among them, Q eIt is the electromagnetic volume loss density; it represents the volume loss density in the electromagnetic field. The loss density is due to the Joule heat generated inside the material when the current flows under the action of the electric field.

[0057] In some specific implementation schemes, in step S2, the thermal simulation software is an electromagnetic-thermal collaborative simulation studio; the background temperature is 50°C-200°C, specifically, the RF dummy load absorbing structure absorbs the energy of electromagnetic waves and converts it into heat, thereby causing its own temperature to rise, while taking into account changes in the external temperature. By simulating and analyzing the temperature distribution of the RF dummy load absorbing structure in the range of 50°C-200°C, the simulated temperature is a steady-state temperature, that is, the absorption and release of heat reach a balance condition; the boundary condition used in the thermal simulation is an open boundary.

[0058] In some specific implementations, in step S2, the steady-state temperature distribution is calculated as:

[0059] ρC p u·▽T+▽·q=Q e +Q ted ; where ρ is the resistivity, C p is the specific heat capacity, u is the displacement, ▽T is the temperature gradient, q is the heat flux, Q ted It is thermoelastic damping; it represents the process of heat conduction in the material, including the influence of internal and external heat sources;

[0060] Furthermore, the resistivity Where R is the resistance, S is the cross-sectional area, and d is the length; it represents the relationship between the resistivity of a material and its geometric dimensions;

[0061] Heat flux q = -k▽T, where k is thermal conductivity; it means that the heat flux is proportional to the negative value of the temperature gradient, that is, heat flows from the high temperature area to the low temperature area;

[0062] Thermoelastic Damping Where α is the coefficient of thermal expansion, T is the temperature, is the rate of change of the strain tensor with time, that is, the strain rate tensor; it represents the heat loss caused by the internal stress of the material due to temperature changes.

[0063] In some specific implementations, in step S3, the strain tensor of thermal deformation is calculated as:

[0064] Among them, u is displacement, T is temperature; it indicates the degree of deformation of the material after being subjected to force;

[0065] The calculation of solid heat transfer is: ▽·S+F v = 0, where S is the thermal strain, F vis the volume force; it represents the distribution of thermal strain in the material and the balance of volume force;

[0066] The elastic stress is calculated as: S el =C:ε el , where S el is the elastic stress, C is the elastic modulus, ε el It is elastic strain; it represents the relationship between the deformation and stress of a material after being subjected to force;

[0067] Furthermore, the elastic modulus C=C(E,υ), where E is the electric field and υ is the strain; indicates that the elastic modulus of the material will change with changes in the electric field and strain.

[0068] Specifically, thermal deformation occurs under the combined effect of external temperature and its own temperature rise, and stress analysis is performed using thermal field distribution as the mechanical field source. Considering the actual simulation model, the outer surface of the RF dummy load is used as the displacement surface to calculate the thermal deformation distribution of the structure under different ambient temperatures. The increase in temperature causes thermal deformation, and different grid densities represent different degrees of deformation. The more network density, the greater the degree of deformation.

[0069] In some specific implementations, the step S4 includes the following sub-steps:

[0070] S41, re-importing the radio frequency dummy load absorbing structure after thermal deformation obtained in step S3 into the simulation software in step S1, and updating the material properties of the radio frequency dummy load absorbing structure, including the dielectric constant and conductivity involved;

[0071] S42. According to the simulation process of electromagnetic-thermal-mechanical multi-physics fields in the simulation software, the thermal deformation caused by temperature and the nonlinear changes of material parameters with temperature are imported for simulation, and the electromagnetic properties affected by temperature are analyzed and visualized.

[0072] In step S41, the dielectric constant ε th The calculation of ε is: th =β(TT ref ), where β is the temperature coefficient, T ref is the reference temperature; it means that the dielectric constant will change with the change of temperature;

[0073] The conductivity σ is calculated as: Where ρo is the reference resistivity; it indicates that the conductivity will change with the temperature.

[0074] Specifically, this stage considers the effect of thermal deformation caused by electromagnetic-thermal multi-physics field coupling on the absorption performance of the RF dummy load absorbing structure, and considers the change of boundary material properties with temperature. Although some parameters such as thermal expansion coefficient and Young's modulus are less affected by temperature, the relative dielectric constant is more affected by temperature. Therefore, the thermal deformation caused by temperature and the nonlinear change of material parameters with temperature are imported into the electromagnetic studio for simulation, and finally the electromagnetic performance of the RF dummy load absorbing structure under the influence of temperature is obtained.

[0075] The above is based on the ideal embodiment of the present invention. Through the above description, it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description, and it is intended to include all changes within the meaning and scope of the equivalent elements of the claims. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0076] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A radio frequency dummy load multi-physics field simulation method, characterized in that: The following steps are involved: S1. Analyze the electromagnetic characteristics of the RF dummy load absorbing structure through simulation software, and calculate the power loss distribution of each part in the post-processing stage; S2. Import the power loss distribution obtained by electromagnetic characteristic analysis into thermal simulation software, set the corresponding background temperature, and perform thermal simulation to calculate the steady-state temperature distribution of the RF dummy load absorbing structure in the oil medium; S3. The temperature distribution obtained by thermal simulation is used as a load and applied to the thermal-mechanical coupling analysis to perform a structural analysis of the RF dummy load absorbing structure to obtain the thermal deformation of each part; S4. Re-import the RF dummy load absorbing structure after thermal deformation, update the material properties of the RF dummy load absorbing structure, import the thermal deformation caused by temperature and the nonlinear change of material parameters with temperature for simulation, and finally obtain the electromagnetic performance of the RF dummy load absorbing structure affected by temperature.

2. A radio frequency dummy load multi-physical field simulation method according to claim 1, characterized in that: The step S1 includes the following sub-steps: S11. Create a three-dimensional geometric model of the RF dummy load in the simulation software, including the metal parts, dielectric materials and air gap involved; S12. Assign electromagnetic material properties to different materials in the model, including the dielectric constant and conductivity involved; S13, select a high-frequency electromagnetic field solver, set the transmission signal operating frequency and signal power when the external temperature does not change, perform simulation, and calculate the electric field, current and loss distribution of the RF dummy load absorbing structure.

3. A radio frequency dummy load multi-physical field simulation method according to claim 2, characterized in that: In the step S11, the simulation software is the commercial simulation software CST, and is CST Microwave Studio.

4. The multi-physics field simulation method of a radio frequency dummy load according to claim 2, characterized in that: In the step S13, the relationship between the electric field and the electric potential is calculated: E=-▽V; wherein E is the electric field and V is the electric potential; Calculate the relationship between current density and electric field: J = -σE + J e ; Where J is the current density, σ is the conductivity, and Je is the current density generated outside the material; Calculate the electromagnetic volume loss density: Among them, Q e is the electromagnetic volume loss density.

5. The multi-physics field simulation method of radio frequency dummy load according to claim 1, characterized in that: In step S2, the thermal simulation software is an electromagnetic-thermal collaborative simulation studio.

6. The method for multi-physical field simulation of a radio frequency dummy load according to claim 1, characterized in that: In the step S2, the background temperature is 50°C-200°C; and the boundary condition adopted by the thermal simulation is an open boundary.

7. The multi-physics field simulation method of radio frequency dummy load according to claim 1, characterized in that: In step S2, the steady-state temperature distribution is calculated as: Where ρ is the resistivity, C p is the specific heat, u is the displacement, is the temperature gradient, q is the heat flux, Q ted is the thermoelastic damping; Resistivity Where R is the resistance, S is the cross-sectional area, and d is the length; Heat flux Where k is the thermal conductivity; Thermoelastic Damping Where α is the coefficient of thermal expansion, T is the temperature, is the rate of change of the strain tensor with time.

8. The multi-physics field simulation method of radio frequency dummy load according to claim 1, characterized in that: In the step S3, the strain tensor of the thermal deformation is calculated as: Where u is the displacement and T is the temperature; The calculation of solid heat transfer is: Where S is the thermal strain, F v It is the volume force; The elastic stress is calculated as: S el =C:ε el , where S el is the elastic stress, C is the elastic modulus, ε el is the elastic strain; Elastic modulus C = C(E,υ), where E is the electric field and υ is the strain.

9. The method for multi-physical field simulation of a radio frequency dummy load according to claim 1, characterized in that: The step S4 includes the following sub-steps: S41, re-importing the radio frequency dummy load absorbing structure after thermal deformation obtained in step S3 into the simulation software in step S1, and updating the material properties of the radio frequency dummy load absorbing structure, including the dielectric constant and conductivity involved; S42. According to the simulation process of electromagnetic-thermal-mechanical multi-physics fields in the simulation software, the thermal deformation caused by temperature and the nonlinear changes of material parameters with temperature are imported for simulation, and the electromagnetic properties affected by temperature are analyzed and visualized.

10. A radio frequency dummy load multi-physical field simulation method according to claim 9, characterized in that: In the step S41, the dielectric constant εth is calculated as: ε th =β(TT ref ), where β is the temperature coefficient, T ref is the reference temperature; The conductivity σ is calculated as: where ρo is the reference resistivity.

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