A method of causality modeling of a radio frequency transmission line

Abstract

The application discloses a causality modeling method of a radio frequency transmission line, which comprises the following steps: obtaining a frequency-dependent complex dielectric constant according to a measurement frequency, a real dielectric constant of a dielectric material and a dielectric loss tangent of a substrate at the measurement frequency, a pre-set low roll-off frequency and a high roll-off frequency; obtaining an electric conductance and an electric capacity of the transmission line by using the frequency-dependent complex dielectric constant ε r ; calculating a direct current resistance and an alternating current resistance of a conductor; adding a virtual part of an existing frequency-dependent resistance term to an inductance in the form of an inductance to obtain a frequency-dependent inductance; and calculating a frequency-dependent resistance by using a smoothing function to obtain a complete causality model of the radio frequency transmission line. In the causality model of the radio frequency transmission line obtained by the method, the frequency-dependent complex dielectric constant and the inductance meet the causality relationship more, the alternating current resistance R ac has higher precision, and the direct current resistance and the alternating current resistance are smoothing and continuous, so that the transition from the direct current to the skin effect part is smoother.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of radio frequency transmission line modeling, and in particular to a causality modeling method of radio frequency transmission line. BACKGROUND

[0002] In order to know the performance of the designed circuit before the chip is manufactured, the design engineer must convert all the devices on the circuit into physical models by means of electronic design software, and then perform simulation of other performances such as transient, alternating small signal, noise, etc. by means of a circuit simulation software (Simulation Program with Integrated Circuit Emphasis, HSPICE). The most common device on the circuit board is a transmission line, and the external physical representation of the transmission line is resistor-inductor-conductor-capacitor (RLGC) and length. The transmission line system is often represented by S parameters.

[0003] The transfer function of the transmission line can be represented as:

[0004] H(ω) = e -γx

[0005]

[0006] The inductance l, the capacitance c, the resistance r, and the length x, if the causality of the transmission line is to be guaranteed, H needs to satisfy:

[0007] H(-ω) = H(ω)

[0008] h(t) = 0, for t < 0

[0009] Based on the transmission line theory, when the radio frequency transmission line is modeled, the RLGC(f) is calculated through a closed-form expression, and then the characteristic impedance Z and the propagation constant γ of the transmission line are obtained from the RLGC(f), and finally the S parameters are calculated. Under the existing model, constant LC values are generally used for calculation. Although the model S parameter results and the measured S parameter results can be very well matched in the frequency domain, non-causal phenomena will occur in the time domain, which may lead to non-convergence in circuit simulation. In high-frequency circuit simulation, conductor loss and dielectric loss are particularly important. Such losses not only cause signal attenuation, but also cause signal distortion. Such distortion will in turn introduce inter-symbol interference. Therefore, it is very important to accurately characterize the time-domain characteristics of the transmission line. The existing model cannot correctly characterize the time-domain effect, and the general problem is that the model has non-causal behavior. SUMMARY

[0010] In order to solve the defects of the prior art, the present application aims to provide a causality modeling method of a radio frequency transmission line, so that the complex permittivity and the inductance of the causality RLGC(f) change with the frequency, the causality is better met, and the problem that the causality cannot be ensured in time domain simulation of the non-causality RLGC(f) transmission line model is solved.

[0011] In order to achieve the above-mentioned purpose, the present application provides a causality modeling method of a radio frequency transmission line, comprising the following steps:

[0012] According to the measured frequency, the real permittivity of the dielectric material and the dielectric loss tangent of the substrate at the measured frequency, the pre-set low roll-off frequency and the high roll-off frequency, the frequency-dependent complex permittivity is obtained;

[0013] The frequency-dependent complex permittivity is used to obtain the conductance and the capacitance of the transmission line;

[0014] The direct current resistance and the alternating current resistance of the transmission line are calculated;

[0015] The frequency-dependent inductance is calculated;

[0016] The frequency-dependent resistance is calculated using a smoothing function to obtain a complete causality model of the radio frequency transmission line.

[0017] Further, the causality model of the radio frequency transmission line is:

[0018]

[0019] Wherein, R is the frequency-dependent resistance, R dc is the direct current resistance, R ac is the alternating current resistance, f smooth (R dc , R ac ) is a smoothing function, L is the frequency-dependent inductance, L dc is the direct current inductance, f is the simulation frequency, ε0 is the vacuum permittivity, are the real part and the imaginary part of the frequency-dependent complex permittivity respectively, G is the conductance, C is the capacitance, K g is the dielectric filling coefficient.

[0020] Further, the expression of the smoothing function is:

[0021] Wherein, coth is the hyperbolic cotangent function.

[0022] Further, the complex permittivity is a function changing with the frequency, and there is a certain constraint condition between the real part and the imaginary part to meet the causality, and the equivalent expression is as follows:

[0023]

[0024] wherein ε r is the complex permittivity, f L is the low roll-off frequency of tan δ(f), f H is the high roll-off frequency of tan δ(f); when the simulation frequency is f E , the coefficient is calculated as ε r (f E ) = ε r , tan δ(f E ) = tan δ, ε r , tan δ are the real permittivity and the dielectric loss tangent of the dielectric material at the simulation frequency, respectively.

[0025] Further, the step of calculating the frequency-dependent complex permittivity is calculated by the following expression:

[0026]

[0027] wherein the coefficient f E is the measurement frequency, ε r , tan δ are the real permittivity and the dielectric loss tangent of the dielectric material at the measurement frequency, respectively, f L , f H are the low roll-off frequency and the high roll-off frequency set by the user, respectively, ε r is the complex permittivity, j is the imaginary unit, arg is the principal value of the argument, is the modulus.

[0028] Further, the direct current resistance and the alternating current resistance are calculated by the following formula:

[0029]

[0030] wherein R dc is the direct current resistance, R ac is the alternating current resistance, R s is the skin resistance, w is the length of the transmission line, t is the thickness of the transmission line, and σ is the conductivity of the transmission line.

[0031] Further, the step of calculating the frequency-dependent inductance further comprises:

[0032] The imaginary part of the original frequency-dependent resistance term is added to the direct current inductance in the form of inductance to obtain the frequency-dependent inductance; the expression of the original frequency-dependent resistance term is: R = R dc + (1 + j)R ac According to the imaginary part R ac , an item in the form of inductance is added to the inductance The expression of the frequency-dependent inductance is obtained: L dc is the DC inductance, f is the simulation frequency, R ac is the AC resistance.

[0033] Further, the method further comprises: calculating the characteristic impedance and the propagation constant through the radio frequency transmission line causality model, and then calculating the two-port S parameters, and the calculation formula is as follows:

[0034]

[0035]

[0036] Wherein, Z0 is the initial characteristic impedance, l is the length of the transmission line, R(f), L(f), G(f), C(f) are the frequency-dependent resistance, inductance, conductance and capacitance per unit length of the transmission line respectively, Z(f), γ(f) are the calculated frequency-dependent characteristic impedance and propagation constant respectively, j is the imaginary unit, ω is the angular frequency, cosh is the hyperbolic cosine function, sinh is the hyperbolic sine function, S 22 , S 11 , S 21 , S 12 are the characteristic elements of the two-port S parameters.

[0037] To achieve the above object, the present application further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor is used for executing the computer program stored in the memory to realize the causality modeling method of the radio frequency transmission line.

[0038] To achieve the above object, the present application further provides a computer readable storage medium, wherein the storage medium stores a computer program, and the computer program is loaded and executed by a processor to realize the causality modeling method of the radio frequency transmission line.

[0039] The causality modeling method of the radio frequency transmission line provided by the present application has the following beneficial effects compared with the prior art:

[0040] In the causality model RLGC(f) obtained by the present application, the complex permittivity and the inductance changing with the frequency more meet the causality relationship, and the AC resistance R ac has higher precision, and the smooth and continuous DC resistance and the AC resistance are used, so that the transition from the DC to the skin part is smoother.

[0041] Other features and advantages of the present application will be described in the following description, and some of them will become apparent from the description, or will be understood by those skilled in the art through implementation of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0042] The accompanying drawings, which are included to provide a further understanding of the application and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

[0043] Figure 1 A schematic diagram of a microstrip transmission line structure according to an embodiment of the application;

[0044] Figure 2 A comparison chart of results of the unit length AC resistance R ac in the prior art and the application;

[0045] Figure 3 A comparison chart of results of R in the prior art without smoothing and in the application with smoothing;

[0046] Figure 4 A comparison chart of the real part of the complex permittivity in the prior art and the application;

[0047] Figure 5 A comparison chart of the imaginary part of the complex permittivity in the prior art and the application;

[0048] Figure 6 A flow chart of a causality modeling method of a radio frequency transmission line according to an embodiment of the application;

[0049] Figure 7 A comparison chart of the attenuation of the S parameter characterization element S 21 in the prior art and the application according to an embodiment of the application;

[0050] Figure 8 A comparison chart of the phase of the S parameter characterization element S 21 in the prior art and the application according to an embodiment of the application;

[0051] Figure 9 A comparison chart of the time domain response in the prior art and the application according to an embodiment of the application;

[0052] Figure 10 A schematic diagram of an electronic device structure according to an embodiment of the application. DETAILED DESCRIPTION

[0053] The preferred embodiments of the application will be described hereinafter with reference to the drawings, in which the preferred embodiments of the application will be described. It should be understood that the preferred embodiments described hereinafter are only used to explain and illustrate the application, and are not used to limit the application.

[0054] Embodiments of the present application will be described in more detail with reference to the drawings. While several embodiments of the application are shown in the drawings, it is not intended that the application be limited to the embodiments shown, and it is understood that the application can be carried out by various forms. It is also noted that terminology from the field of the art can be used in describing the embodiments, and that equivalents of such terminology are implied where appropriate. It is to be understood that the drawings and descriptions are exemplary and explanatory only and are not intended to be limiting on the application, which is defined by the claims.

[0055] The term "comprising" and variations thereof as used herein are used inclusively, i.e., "comprising, but not limited to." The term "based on" is "based at least in part on." The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments." Related terms are to be interpreted in a like fashion.

[0056] It should be noted that the terms "first", "second", and the like, as can be used in the specification, are employed for purposes of clarity only and not as terms of limitation. It is to be understood that where these terms are used, they are not to be construed as singling out one device or component for a singular use, but in actual use there can be several of each of these devices, and in or more of these devices can be of any type.

[0057] It should be noted that the terms "one", "multiple", as can be used in the specification, are illustrative and not limiting, and those skilled in the art will understand that "one" or "a" should be interpreted as "one or more" unless the context clearly indicates otherwise. "Multiple" should be interpreted as two or more.

[0058] The causality modeling method of the radio frequency transmission line comprises:

[0059] According to the measured frequency, the real dielectric constant of the dielectric material and the dielectric loss tangent of the substrate at the measured frequency, the pre-set low roll-off frequency and the high roll-off frequency, the frequency-dependent complex dielectric constant is calculated;

[0060] The conductance and the capacitance of the transmission line are calculated using the frequency-dependent complex dielectric constant;

[0061] The DC resistance and the AC resistance of the conductor are calculated;

[0062] The frequency-dependent inductance is calculated;

[0063] The frequency-dependent resistance is calculated using a smoothing function to obtain a complete radio frequency transmission line causality RLGC(f) model.

[0064] In the prior art transmission line model, RLGC(f) is generally expressed as:

[0065]

[0066] where R dc and Ldc is the DC resistance of the rectangular conductor, f is the simulation frequency, R ac ∝R s (R ac ∝R s ), R ac is the AC resistance, R s is the skin resistance, K g is the dielectric filling factor, ε0is the vacuum permittivity, ε r = ε r -j·(ε r · tan δ), (Real part of ε r ) and (Imaginary part of ε r ) are not frequency dependent, which is one of the sources of non-causal time-domain response. The complex permittivity ε r characterizes the propagation and reflection behavior of electromagnetic waves in a dielectric material, ε r is the real permittivity obtained from the dielectric material test at a specific frequency.

[0067] The transmission line model in the present invention is represented as:

[0068]

[0069] where the imaginary part of the frequency-dependent resistance term R is added to the inductance term L in the form of inductance, R dc and R ac are calculated as follows, f smooth (R dc , R ac ) are to smooth the continuous functions of R dc and R ac :

[0070]

[0071] where w is the length of the transmission line, t is the thickness of the transmission line, σ is the conductivity of the transmission line, coth is the hyperbolic cotangent function.

[0072] The complex permittivity ε r is a function of frequency, and there is a certain constraint condition between the real part and the imaginary part to meet the causal relationship:

[0073]

[0074] Substituting f = f E into the equation gives:

[0075]

[0076] where fL For the low roll-off frequency of tanδ(f), f H For the high roll-off frequency of tanδ(f), when the simulation frequency is f E When, the calculated ε r (f E )=ε r ,tanδ(f E ) = tanδ, where arg is the principal argument value. To obtain the model.

[0077] Another factor influencing causality is in the inductor L. Item. At this point, the complete causal RLGC(f) model has been completed.

[0078] The following section uses a microstrip line as an example to compare the causal RLGC(f) model of the transmission line in the prior art with that of the present invention, and compares the AC resistance R of the two. ac The difference, f smooth (R dc R ac The effect of the smoothing function, and the difference in complex permittivity.

[0079] Figure 1 This is a schematic diagram of a microstrip transmission line structure according to an embodiment of the present invention, such as... Figure 1 As shown, in the microstrip transmission line structure, w and l are the length and width of the transmission line, t is the thickness of the transmission line, h is the substrate thickness, σ is the transmission line conductivity, and tanδ is the dielectric loss tangent of the substrate.

[0080] Figure 2 The AC resistance R per unit length in the prior art and in this invention ac The results are shown in the comparison chart, where old-Rac is the AC resistance R of the existing technology. ac new-Rac is the AC resistance R of this invention. ac The corresponding microstrip transmission line structural parameters are w = 25u, h = 100u, t = 4u, and σ = 41.7e6.

[0081] As you can see, Figure 3 The image shows a comparison of the R results of the prior art without smoothing and the smoothed result of this invention, with parameters w = 25u, h = 100u, t = 4u, and σ = 41.7e6.

[0082] A comparison of the real and imaginary parts of the complex permittivity in the prior art and the present invention is performed, with parameter values ​​ε. r =9.8, tanδ=0.01, f H =1e12,f L =1e3,f E=1e9, which shows that the ε generated in this invention varies with frequency. r The characteristic curves of (f) and tanδ(f) are as follows: Figure 4 and Figure 5 As shown, where Figure 4 A comparison graph of the real part of the complex permittivity of existing technology and the present invention (the vertical axis title is denoted by er for ε). r The horizontal axis represents frequency (Hz). Figure 5 This is a comparison graph of the imaginary part of the complex permittivity of the prior art and the present invention (the vertical axis is denoted by tanδ, and the horizontal axis is frequency (Hz)).

[0083] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0084] Figure 6 This is a flowchart of a causal modeling method for radio frequency transmission lines according to an embodiment of this application, such as... Figure 6 As shown, firstly, in step 101, the complex permittivity is calculated: f E It measures frequency, ε r tanδ and tanδ are the measured values ​​of the dielectric material at this measurement frequency. The user sets the low roll-off frequency f. L and high roll-off frequency f H The frequency-dependent complex permittivity ε is obtained from the above expression (4). r .

[0085] In step 102, the frequency-dependent complex permittivity ε is used. r Calculate the conductance and capacitance of the transmission line.

[0086] In this embodiment, the frequency-dependent complex permittivity ε is used. r Substituting into the above expression (1), calculate the LGC(f) of the microstrip transmission line (including the frequency-dependent inductance L(f), conductance G(f), and capacitance C(f)). At this time, the frequency-dependent inductance L(f) is still missing. Item section.

[0087] In step 103, calculate the DC resistance and AC resistance. R is calculated using expression (2). dc R ac .

[0088] In step 104, the frequency-dependent inductance is calculated.

[0089] In this embodiment, the imaginary part (Ri) of the frequency-dependent resistance term R is... ac This is added to the inductance term L in the form of an inductor to supplement the missing part of the frequency-dependent inductance L(f).

[0090] In step 105, the frequency-dependent resistance is calculated using the smoothing function. The frequency-dependent resistance R(f) is calculated using the smoothing function of expression (3) above, obtaining the complete RLGC(f) model.

[0091] In step 106, the characteristic impedance Z(f) and the propagation constant γ(f) are calculated by RLGC(f), and then the two-port S parameters are calculated. The S parameters are mathematically a matrix form, and the two-port S parameters have four characteristic elements S 11 , S 21 , S 12 , S 22 . The calculation formula is as follows, where Z0 is the initial characteristic impedance (50 Ω in this embodiment), l is the length of the transmission line, R(f), L(f), G(f), and C(f) are the transmission line unit length frequency-dependent resistance, inductance, conductance, and capacitance calculated above, respectively, j is the imaginary unit, ω (= 2πf) is the angular frequency, cosh is the hyperbolic cosine function, and sinh is the hyperbolic sine function:

[0092]

[0093] In this embodiment, the S parameter results of the prior art and the present application are compared. Figure 7 is a comparison chart of the attenuation of the S parameter characteristic element S 21 of the prior art according to the embodiment of the present application and the present application. The horizontal coordinate is frequency (frequency (Hz)), and the vertical coordinate is the DB value of the |S21| attenuation curve; Figure 8 is a comparison chart of the phase of the S parameter characteristic S21 of the prior art according to the embodiment of the present application and the present application. The horizontal coordinate is frequency (frequency (Hz)), and the vertical coordinate is phase, with radian (rad) as the unit. As shown in Figure 7 and Figure 8 , it can be seen that the conductor loss of the new model of the present application is larger than that of the prior art (libre), so the attenuation of the characteristic S21 is more obvious. The complex permittivity of the new model of the present application varies with frequency, and there is a difference in phase compared with the frequency-independent complex permittivity of the prior art model.

[0094] In this embodiment, a time-domain pulse signal of is input at one end of the transmission line, and the time-domain response (Normalized Waveform) is observed at the other end, where t is time, τ0= 1e-9, and n = 4. Figure 9 is a comparison chart of the time-domain response of the prior art according to the embodiment of the present application and the present application. Under the same input signal, libre is the time-domain response of the prior art, and new is the time-domain response of the present application, as shown inFigure 9 As shown by the comparison of the time domain response results, it can be seen that the transmission line model of the application has a shorter rising time in the time domain response (new line) of the pulse, and the transmission line model of the prior art has a longer rising time in the time domain response (libre line) of the pulse, so that the transmission line model of the application has causality and meets the causality relationship; the transmission line model of the prior art has poor causality and does not meet the causality relationship.

[0095] Compared with the prior art, the application has the following advantages:

[0096] 1) The complex permittivity changing with frequency better meets the causality relationship;

[0097] 2) The imaginary part of the frequency-dependent resistance term R is added to L, so that L better meets the causality relationship;

[0098] 3) The alternating current resistance R ac has higher precision;

[0099] 4) f smooth (R dc , R ac ) makes the transition from the direct current to the skin effect part smoother.

[0100] In an embodiment of the application, an electronic device is also provided, Figure 10 As shown in the structural schematic diagram of the electronic device according to the embodiment of the application, Figure 10 The electronic device of the application comprises a processor 1001 and a memory 1002, wherein,

[0101] The memory 1002 stores a computer program, and the computer program, when read and executed by the processor 1001, performs the steps in the causality modeling method embodiment of the radio frequency transmission line as described above.

[0102] In an embodiment of the application, a computer readable storage medium is also provided, and the computer readable storage medium stores a computer program, wherein the computer program is set to execute the steps in the causality modeling method embodiment of the radio frequency transmission line as described above when running.

[0103] In the embodiment, the computer readable storage medium can include but is not limited to a U disk, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk, and various media that can store computer programs.

[0104] Those skilled in the art can understand that the above only describes the preferred embodiments of the present application and is not used to limit the present application, and although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or make equivalent replacements to some technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of causality modeling of a radio frequency transmission line, the method comprising: The method comprises the following steps: According to the measurement frequency, the real dielectric constant of the dielectric material and the dielectric loss tangent of the substrate at the measurement frequency, the pre-set low roll-off frequency and the high roll-off frequency, the frequency-dependent complex dielectric constant is obtained; Using the frequency-dependent complex dielectric constant, the conductance and the capacitance of the transmission line are obtained; The DC resistance and the AC resistance of the transmission line are calculated; The frequency-dependent inductance is calculated; The frequency-dependent resistance is calculated using a smoothing function to obtain a complete RF transmission line causality model; The RF transmission line causality model is: where R is the frequency dependent resistance, R dc is the DC resistance, R ac is the AC resistance, f smooth (R dc , R ac ) is a smoothing function, L is the frequency dependent inductance, L dc is the DC inductance, f is the simulation frequency, ε0 is the vacuum permittivity, are the real and imaginary parts of the frequency dependent complex permittivity, G is the conductance, C is the capacitance, K g is the dielectric filling factor.

2. The method for causality modeling of a radio frequency transmission line of claim 1, wherein, The expression of the smoothing function is: where coth is the hyperbolic cotangent function; j is the imaginary unit.

3. The method for causality modeling of radio frequency transmission lines of claim 1, wherein, The complex dielectric constant is a function of frequency, and there is a certain constraint condition between the real part and the imaginary part to meet the causality, and the equivalent expression is as follows: wherein ε r is the complex permittivity, f L is the low roll-off frequency of tan δ(f), f H is the high roll-off frequency of tan δ(f); when the simulation frequency is f E , the coefficient is calculated as ε r (f E ) = ε r , tan δ(f E ) = tan δ, ε r , tan δ are the real permittivity and the dielectric loss tangent of the dielectric material at the simulation frequency, respectively; j is the imaginary unit.

4. The method for causality modeling of radio frequency transmission lines of claim 1, wherein, The step of calculating the frequency-dependent complex dielectric constant is calculated using the following expression: wherein the coefficient f E is the measurement frequency, ε r , tan δ are the real dielectric constant and the dielectric loss tangent of the substrate at the measurement frequency, respectively, f L , f H are the low and high roll-off frequencies set by the user, respectively, ε r is the complex dielectric constant, j is the imaginary unit, arg is the principal value of the argument, is the modulus.

5. The method for causality modeling of radio frequency transmission lines of claim 1, wherein, The DC resistance and the AC resistance are calculated using the following formula: where R dc is the DC resistance, R ac is the AC resistance, R s is the skin resistance, w is the length of the transmission line, t is the thickness of the transmission line, and σ is the conductivity of the transmission line.

6. The method for causality modeling of radio frequency transmission lines of claim 1, wherein, The step of calculating the frequency-dependent inductance further comprises: The imaginary part of the original frequency-dependent resistance term is taken with the inductance and the DC inductance to obtain the frequency-dependent inductance; The expression of the original frequency-dependent resistance term is: R = R dc +(1+j)R ac According to the imaginary part R ac , an item in the form of inductance is added to the inductance The expression of the frequency-dependent inductance is obtained: L dc is the DC inductance, f is the simulation frequency, R ac is the AC resistance; j is the imaginary unit.

7. The method for causality modeling of radio frequency transmission lines of claim 1, wherein, Further comprising: The characteristic impedance and the propagation constant are calculated through the RF transmission line causality model, and the two-port S parameters are calculated, and the calculation formula is as follows: where Z0is the initial characteristic impedance, / is the length of the transmission line, R(f), L(f), G(f), C(f) are the frequency dependent resistance, inductance, conductance and capacitance per unit length of the transmission line, Z(f), γ(f) are the calculated frequency dependent characteristic impedance and propagation constant, j is the imaginary unit, ω is the angular frequency, cosh is the hyperbolic cosine function, sinh is the hyperbolic sine function, S 22 , S 11 , S 21 , S 12 are the representation elements of the two-port S-parameters.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor is used to execute the computer program stored in the memory to realize the steps of the causality modeling method of the RF transmission line according to any one of claims 1-7.

9. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, and the processor loads and executes the computer program to realize the steps of the causality modeling method of the RF transmission line according to any one of claims 1-7.

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