Airborne antenna port coupling electromagnetic simulation analysis method

Abstract

The invention belongs to the field of electromagnetic compatibility, and particularly relates to an airborne antenna port coupling electromagnetic simulation analysis method, which comprises the following steps of: S1, constructing an electromagnetic environment numerical calculation model according to acquired parameters of an interference source, parameters of an airborne antenna and a position relationship between the interference source and the airborne antenna; s2, performing normalized coupling simulation through electromagnetic full-wave simulation software to obtain normalized coupling strength of the airborne antenna under irradiation of external far-field plane waves; s3, on the basis of an electromagnetic environment numerical calculation model, a radiation source propagation attenuation model is used to calculate the electric field intensity, the polarization mode and the time-frequency spectrum parameter when the interference signal of the interference source arrives at the airborne antenna; and S4, calculating the normalized coupling strength in a linear calculation mode to obtain actual coupling power.

Description

Technical Field

[0001] The present application belongs to the field of electromagnetic compatibility, and in particular relates to an electromagnetic simulation analysis method for airborne antenna port coupling. Background Art

[0002] Airborne antennas are the basic carriers for aircraft to complete communication, navigation, identification, ranging, detection and other capabilities. Airborne antenna port electromagnetic coupling simulation is an important part of the design of modern aircraft electromagnetic protection capabilities. Since the 21st century, the intensity and complexity of the aircraft's external electromagnetic environment have increased exponentially, and the mechanism of airborne antenna interference has become extremely complex. Traditional antenna port coupling simulation and testing based on fixed external electromagnetic environment indicators are difficult to meet the needs. Therefore, a new method that combines electromagnetic calculation, antenna simulation, and numerical analysis is needed to effectively evaluate antenna port coupling and support the pre-forward design of electromagnetic compatibility of airborne antennas. Summary of the invention

[0003] In order to solve the above problems, the present application provides an airborne antenna port coupling electromagnetic simulation analysis method, including:

[0004] Step S1: constructing an electromagnetic environment numerical calculation model according to the acquired interference source parameters, airborne antenna parameters, and the position relationship between the interference source and the airborne antenna;

[0005] Step S2: performing normalized coupling simulation using electromagnetic full-wave simulation software to obtain the normalized coupling strength of the airborne antenna under external far-field plane wave illumination;

[0006] Step S3: Based on the electromagnetic environment numerical calculation model, the radiation source propagation attenuation model is used to calculate the electric field strength, polarization mode, and time-frequency spectrum parameters of the interference signal of the interference source when it reaches the airborne antenna;

[0007] Step S4: Based on the electric field strength, polarization mode, and time-frequency spectrum parameters of the interference signal at the point where the interference signal reaches the airborne antenna, the normalized coupling strength is calculated in a linear calculation manner to obtain the actual coupling power;

[0008] Step S5: Change the airborne antenna parameters and the position relationship between the interference source and the airborne antenna, and jump to step S3 until the actual coupling power of the relative positions of all required airborne antennas and interference sources is obtained.

[0009] Preferably, the method further comprises step S6: taking the saturation threshold of the airborne antenna of the receiver as a reference, comparing the actual coupling strength with the saturation limit, and judging the working state of the airborne antenna of the receiver.

[0010] Preferably, the airborne antenna parameters include time, frequency, space, energy, modulation, and polarization domain parameters.

[0011] Preferably, atmospheric transmission attenuation and atmospheric absorption loss meteorological parameters are introduced when using a radiation source propagation attenuation model to calculate the electric field strength, polarization mode, and time-frequency spectrum parameters of the interference signal of the interference source arriving at the airborne antenna.

[0012] Preferably, the electromagnetic full-wave simulation software includes CST simulation software and FEKO simulation software.

[0013] Preferably, the specific method for calculating the normalized coupling strength by linear extrapolation includes:

[0014] Step 41: Obtain the polarization mode determined in step S3, which is the same as the polarization mode of the airborne antenna. Based on the polarization mode, the angle between the interference source and the polarization direction of the airborne antenna is calculated as θ, and the coupling power P after polarization loss is calculated by substituting it into the polarization loss formula. real1 The actual electric field strength E after polarization loss real1 :

[0015] E real1 =E×cos(θ)

[0016]

[0017] P real1 =P+par 极化

[0018] Where, E is the normalized coupling intensity, P is the normalized coupling power, and P real1 To calculate the coupled power after polarization loss, Par 极化 is the parameter for calculating polarization loss;

[0019] Step 42: The electric field strength E of the interference signal calculated in step S3 when it reaches the airborne antenna real2 , the normalized coupling strength E calculated in step S2, the coupling power after the polarization loss is calculated to obtain the coupling power P after the actual electric field strength is calculated real2 :

[0020]

[0021] P real2 =P real1 +Par 强度

[0022] Par 强度 To calculate the actual electric field strength parameter, P real2 To calculate the coupling power after the actual electric field strength;

[0023] Step 43: Calculate the coupling power P after the actual electric field strength real2Calculate the peak power P of the pulse wave single-frequency narrowband interference signal max , substitute it into the following formula to convert it into average power P avg : Used to represent the actual coupled power.

[0024] Par 脉冲 =20×log(τ / T)

[0025] P avg =P max +Par 脉冲 ;

[0026] Where T is the time spectrum period, τ is the pulse width;

[0027] Step 44: According to the results of step 2 and step 3, the normalized coupling strength corrected average power P avg for:

[0028] P max =P+par 极化 +par 强度 ;

[0029] P avg =P+par 极化 +par 强度 +par 脉冲 .

[0030] The advantages of this application include: the simulation method combines three methods: theoretical calculation of electromagnetic environment, antenna electromagnetic simulation, and electromagnetic numerical analysis, and efficiently and accurately completes the evaluation of the coupling strength of airborne antenna ports under complex electromagnetic environments, solving the pain point of lack of support for antenna electromagnetic compatibility forward design, and can effectively improve aircraft design efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of external electromagnetic environment modeling in a preferred embodiment of the present application

[0032] Figure 2 This is a schematic diagram of airborne antenna port coupling simulation in a preferred embodiment of the present application.

[0033] Figure 3 This is a comparison diagram of the coupling results of the airborne antenna port under different external electromagnetic environments in a preferred embodiment of the present application.

[0034] Figure 4 This is a flow chart of an electromagnetic simulation analysis method for airborne antenna port coupling in a preferred embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be further described in detail in detail and in detail in conjunction with the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design. In the absence of conflict, the embodiments in the present application and the technical features in the embodiments can be combined with each other to obtain new embodiments.

[0036] like Figure 4 As shown, an airborne antenna port coupling electromagnetic simulation analysis method includes:

[0037] Step S1: constructing an electromagnetic environment numerical calculation model according to the acquired interference source parameters, airborne antenna parameters, and the position relationship between the interference source and the airborne antenna;

[0038] Step S2: performing normalized coupling simulation using electromagnetic full-wave simulation software to obtain the normalized coupling strength of the airborne antenna under external far-field plane wave illumination;

[0039] Step S3: Based on the electromagnetic environment numerical calculation model, the radiation source propagation attenuation model is used to calculate the electric field strength, polarization mode, and time-frequency spectrum parameters of the interference signal of the interference source when it reaches the airborne antenna;

[0040] Step S4: Based on the electric field strength, polarization mode, and time-frequency spectrum parameters of the interference signal at the point where the interference signal reaches the airborne antenna, the normalized coupling strength is calculated in a linear calculation manner to obtain the actual coupling power;

[0041] Step S5: Change the parameters of the airborne antenna and the position relationship between the interference source and the airborne antenna, and jump to step S3 until the actual coupling strength of the relative positions of all the required airborne antennas and the interference sources is obtained.

[0042] Preferably, the method further comprises step S6: taking the saturation threshold of the airborne antenna of the receiver as a reference, comparing the actual coupling strength with the saturation limit, and judging the working state of the airborne antenna of the receiver.

[0043] Preferably, the airborne antenna parameters include time, frequency, space, energy, modulation, and polarization domain parameters.

[0044] Preferably, atmospheric transmission attenuation and atmospheric absorption loss meteorological parameters are introduced when using a radiation source propagation attenuation model to calculate the electric field strength, polarization mode, and time-frequency spectrum parameters of the interference signal of the interference source arriving at the airborne antenna.

[0045] Preferably, the electromagnetic full-wave simulation software includes CST simulation software and FEKO simulation software.

[0046] Preferably, the specific method for calculating the normalized coupling strength by linear extrapolation includes:

[0047] Step 41: Obtain the polarization mode determined in step S3, which is the same as the polarization mode of the airborne antenna. Based on the polarization mode, the angle between the interference source and the polarization direction of the airborne antenna is calculated as θ, and the coupling power P after polarization loss is calculated by substituting it into the polarization loss formula. real1 The actual electric field strength E after polarization loss real1 :

[0048] E real1 =E×cos(θ)

[0049]

[0050] P real1 =P+par 极化

[0051] Where E is the normalized coupling intensity, P is the normalized coupling power, and P real1 To calculate the coupled power after polarization loss, Par 极化 is the parameter for calculating polarization loss;

[0052] Step 42: The electric field strength E of the interference signal calculated in step S3 when it reaches the airborne antenna real2 , the normalized coupling strength E calculated in step S2, the coupling power after the polarization loss is calculated to obtain the coupling power P after the actual electric field strength is calculated real2 :

[0053]

[0054] P real2 =P real1 +Par 强度

[0055] Par 强度 To calculate the actual electric field strength parameter, P real2 To calculate the coupling power after the actual electric field strength;

[0056] Step 43: Based on the time-frequency spectrum parameters calculated in step S3 and the linear receiving amplification effect of the receiver on the interference signal, the time-frequency components of the interfered signal are obtained by linear calculation. Taking a stable pulse wave single-frequency narrowband interference signal as an example, its time-frequency spectrum can be simplified as follows:

[0057]

[0058] Where P(t,f) is the time-frequency spectrum of the interference signal. Since it is a pulse signal with a pulse width of τ(s), within one cycle, the signal inside the pulse has a power spectrum s(t,f), and the power spectrum of the signal outside the pulse is 0. For a single-frequency narrowband signal, it can be approximately considered that all the power is concentrated in the main frequency band of the interference signal, so the power spectrum is not analyzed in detail.

[0059] For a pulse signal, there is a peak (instantaneous) power P max (dBm) and average power P avg (dBm), the average power is the time domain integral of the signal spectrum in one cycle, and the peak power is the integral of the interference signal spectrum in the pulse width, expressed as the following formula:

[0060]

[0061]

[0062] Where T is the time spectrum period, τ is the pulse width, and s(t,f) is the power spectrum density of the interference signal;

[0063] The electric field strength of the interference signal of the interference source obtained in step S3 when it reaches the airborne antenna is used to calculate the peak power of the pulse wave single-frequency narrowband interference signal, and it is converted into average power by substituting it into the following formula:

[0064] Par 脉冲 =20×log(τ / T)

[0065] P avg =P max +Par 脉冲

[0066] Step 44: Based on the results of step 2 and step 3, describe the relationship with the actual coupling strength.

[0067] P max =P+par 极化 +par 强度 ;

[0068] P avg =P+par 极化 +par 强度 +par 脉冲 .

[0069] A simulation embodiment based on the above-mentioned airborne antenna port coupling electromagnetic simulation analysis method:

[0070] Based on the previous analysis of the aircraft's purpose, the emission parameters of the external RF interference source of the airborne antenna and its position relationship with the aircraft are counted, and a three-dimensional electromagnetic multi-domain computing scenario is constructed. The interference source position relationship, antenna and RF emission time, frequency, space, energy, modulation, and polarization domain parameters are substituted. The schematic diagram of external electromagnetic environment modeling is shown below. Figure 1 The time-frequency and modulation domain models are mainly analog communications such as amplitude modulation signals and frequency modulation signals, digital communications such as BPSK coding, and radar detection signals such as linear frequency modulation signals. The signal formats are as follows:

[0071] Linear frequency modulation signal:

[0072] AM signal: S AM (t) = [A 0 +m(t)]cosw c (t) = A 0 cosw c (t)+m(t)cosw c (t)

[0073] FM signal:

[0074] BPSK coding: e bpsk (t) = [∑ n a n g(t-nT s )]cosw c t

[0075] The indicators of airspace, energy domain and polarization domain are determined by the RF emission indicators of the interference source.

[0076] Using the radiation source propagation attenuation model, the intensity, polarization, and time-frequency spectrum parameters of the interference signal reaching the airborne antenna are calculated by considering meteorological parameters such as atmospheric transmission attenuation and atmospheric absorption loss. The multi-source composite electromagnetic environment modeling method is as follows:

[0077] Time domain composite model:

[0078] The frequency domain composite model uses short-time Fourier transform to solve the time-varying power spectrum:

[0079]

[0080] The spatial composite model is expressed in the far field condition as:

[0081]

[0082] The normalized coupling intensity of the external far-field plane wave irradiation of the airborne antenna is simulated using electromagnetic full-wave simulation software such as CST and FEKO. The simulation obtains the coupling response of the antenna port under unit field intensity irradiation. The schematic diagram of the airborne antenna port coupling simulation is shown in the figure. Figure 2 shown.

[0083] Based on the target energy, the antenna port coupling response is linearly extrapolated to obtain accurate airborne antenna port coupling simulation analysis results. Taking the target field strength E = 200V / m as an example, the field strength is 1V / m higher than the simulation field strength. Therefore, the antenna port coupling response under unit field strength is increased by 46dB as the estimated antenna port coupling strength in the current electromagnetic environment.

[0084] Modify the parameters of the external interference source to obtain the required port coupling power at the relative position of all airborne antennas and the interference source.

[0085] Summarize the simulation results and compare them with the airborne receiver parameters to evaluate the interference intensity of the external electromagnetic environment on the airborne antenna. Take the receiver saturation threshold as a benchmark to compare whether the coupling strength exceeds the saturation limit and confirm the working status of the receiver in the corresponding external electromagnetic environment.

[0086] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. An airborne antenna port coupling electromagnetic simulation analysis method, characterized in that: include: Step S1: constructing an electromagnetic environment numerical calculation model according to the acquired interference source parameters, airborne antenna parameters, and the position relationship between the interference source and the airborne antenna; Step S2: performing normalized coupling simulation using electromagnetic full-wave simulation software to obtain the normalized coupling strength of the airborne antenna under external far-field plane wave illumination; Step S3: Based on the electromagnetic environment numerical calculation model, the radiation source propagation attenuation model is used to calculate the electric field strength, polarization mode, and time-frequency spectrum parameters of the interference signal of the interference source when it reaches the airborne antenna; Step S4: Based on the electric field strength, polarization mode, and time-frequency spectrum parameters of the interference signal at the point where the interference signal reaches the airborne antenna, the normalized coupling strength is calculated in a linear calculation manner to obtain the actual coupling power; Step S5: Change the airborne antenna parameters and the position relationship between the interference source and the airborne antenna, and jump to step S3 until the actual coupling power of the relative positions of all required airborne antennas and interference sources is obtained.

2. The airborne antenna port coupling electromagnetic simulation analysis method according to claim 1, characterized in that: The method further comprises step S6: taking the saturation threshold of the airborne antenna of the receiver as a reference, comparing the actual coupling strength with the saturation limit, and judging the working state of the airborne antenna of the receiver.

3. The airborne antenna port coupling electromagnetic simulation analysis method according to claim 1, characterized in that: Airborne antenna parameters include time, frequency, space, energy, modulation, and polarization domain parameters.

4. The airborne antenna port coupling electromagnetic simulation analysis method according to claim 1, characterized in that: When using the radiation source propagation attenuation model to calculate the electric field strength, polarization mode, and time-frequency spectrum parameters of the interference signal of the interference source arriving at the airborne antenna, atmospheric transmission attenuation and atmospheric absorption loss meteorological parameters are introduced.

5. The airborne antenna port coupling electromagnetic simulation analysis method according to claim 1, characterized in that: The electromagnetic full-wave simulation software includes CST simulation software and FEKO simulation software.

6. The airborne antenna port coupling electromagnetic simulation analysis method according to claim 1, characterized in that: The specific method for calculating the normalized coupling strength by linear extrapolation includes: Step 41: Obtain the polarization mode determined in step S3, which is the same as the polarization mode of the airborne antenna. Based on the polarization mode, the angle between the interference source and the polarization direction of the airborne antenna is calculated as θ, and the coupling power P after polarization loss is calculated by substituting it into the polarization loss formula. real1 The actual electric field strength E after polarization loss real1 : E real1 =E×cos(θ) P real1 =P+par 极化 Where E is the normalized coupling intensity, P is the normalized coupling power, and P real1 To calculate the coupled power after polarization loss, Par 极化 is the parameter for calculating polarization loss; Step 42: The electric field strength E of the interference signal calculated in step S3 when it reaches the airborne antenna real2 , the normalized coupling strength E calculated in step S2, the coupling power after the polarization loss is calculated to obtain the coupling power P after the actual electric field strength is calculated real2 : P real2 =P real1 +By 强度 Par 强度 To calculate the actual electric field strength parameter, P real2 To calculate the coupling power after the actual electric field strength; Step 43: Calculate the coupling power P after the actual electric field strength real2 Calculate the peak power P of the pulse wave single-frequency narrowband interference signal max , substitute it into the following formula to convert it into average power P avg , used to represent the actual coupled power; By 脉冲 =20×log(τ / T) P avg =P max +By 脉冲 ; Where T is the time spectrum period, τ is the pulse width; Step 44: According to the results of step 2 and step 3, the average power P avg for: P max =P+par 极化 +by 强度 ; P avg =P+par 极化 +by 强度 +by 脉冲 .

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