A method and system for testing low-frequency transmitting performance of a magnetoelectric antenna

Abstract

The application belongs to the technical field of wireless communication, and particularly relates to a magneto-electric antenna low-frequency transmission performance test method and system, which comprises the following steps: in a deep near-field environment of an electromagnetic shielding room, magnetic field intensities of multiple distance points are obtained, and a spatial attenuation gradient is calculated by using a logarithmic difference method; a nonlinear weighting factor is constructed based on the deviation of the gradient and a theoretical attenuation rate, and an induced field offset term based on a distance square ratio is combined to separate invalid induced fields from a mixed field, so that an equivalent radiation source intensity containing only a radiation term is obtained; finally, a far-field effective magnetic field intensity and a radiation efficiency are deduced by using an inverse proportion model. The application solves the problem that low-frequency antenna testing is limited by physical space and the evaluation is false high due to interference of an induced field, and improves the prediction accuracy of long-distance communication capability in a limited space.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology. More specifically, this invention relates to a method and system for testing the low-frequency transmission performance of a magnetoelectric antenna. Background Technology

[0002] With the growing demand for the Internet of Things (IoT), wireless communication applications in complex environments such as underground and underwater are becoming increasingly important. Traditional microwaves struggle to penetrate due to high dielectric loss, while low-frequency and very low-frequency signals, with their strong penetration and diffraction capabilities, have become key solutions. Magnetoelectric antennas, utilizing the magnetoelectric coupling effect, can achieve low-frequency transmission in small sizes, showing great promise in geological exploration; however, accurately assessing their radiation performance remains a design challenge.

[0003] Low-frequency testing of magnetoelectric antennas faces numerous challenges. Low-frequency signals typically have long wavelengths; for example, 100 kHz electromagnetic waves can reach three kilometers in wavelength. Conventional laboratories cannot provide the physical space required for far-field testing, necessitating testing in the deep near-field region. Existing technologies mostly collect data in the near field, attempting to extrapolate far-field performance through attenuation models, but these methods have certain limitations in the deep near-field environment.

[0004] In the deep near-field region, the electromagnetic field is composed of a superposition of induced and radiated fields. The induced field decays cubically with distance, primarily storing energy and not transmitting it, yet it dominates in intensity. The radiated field, which actually transmits energy, decays linearly with distance, resulting in a relatively weak signal. If existing simple total field strength measurement or linear fitting algorithms are used, the invalid induced field will lead to severely inflated test results. Furthermore, the weak decay characteristics of the radiated field are masked by the dramatic decay curve of the induced field, making it difficult for existing algorithms to extract the effective signal. This results in significant errors in the derived far-field performance, hindering practical engineering applications. Summary of the Invention

[0005] To address the technical problem of insufficient accuracy in far-field performance testing of low-frequency transmission of magnetoelectric antennas, the present invention provides solutions in the following aspects.

[0006] In a first aspect, the present invention provides a method for testing the low-frequency transmission performance of a magnetoelectric antenna, comprising:

[0007] The magnetic field strength amplitudes at multiple test distance points within the deep near-field region of the magnetoelectric antenna under test are obtained. Adjacent test distance points are used to form test intervals, and the spatial attenuation gradient of each test interval is obtained. The spatial attenuation gradient is positively correlated with the logarithmic difference of the magnetic field strength amplitude within the corresponding test interval and negatively correlated with the logarithmic difference of the distance. A radiation component weighting factor is obtained based on the deviation between the spatial attenuation gradient and the theoretical attenuation rate of the pure induction field, and the radiation component weighting factor is positively correlated with the deviation. An induction field cancellation term based on the square ratio of the distances between adjacent test distance points is constructed, and combined with the radiation component weighting factor, an equivalent radiation source intensity containing only the radiation term is obtained. The equivalent radiation source intensity is extrapolated to a set far-field distance to obtain the far-field effective magnetic field intensity, and the transmission performance of the magnetoelectric antenna is obtained based on the far-field effective magnetic field intensity.

[0008] This invention effectively identifies the attenuation difference between the induced field and the radiated field by acquiring magnetic field data at multiple distance points within the deep near-field region and calculating the spatial attenuation gradient. Unlike existing technologies that directly measure the total field strength, leading to the induced field masking the radiated field, this invention constructs a radiation component weighting factor based on deviation and an induced field cancellation term based on the square root of the distance. This extracts the weak effective radiation component from the dominant induced field noise, obtaining the equivalent radiation source intensity containing only the radiation term. This solves the problem of severely inflated antenna performance evaluation caused by the inability to distinguish between the induced field and the radiated field in confined physical spaces, as seen in existing technologies. It also improves the accuracy of predicting the long-range communication capability of low-frequency magnetoelectric antennas in laboratory environments.

[0009] Preferably, the spatial decay gradient satisfies the expression:

[0010] ;

[0011] In the formula, Indicates the first Spatial decay gradient of each test interval; , Indicates the first The, the The magnetic field strength amplitude at each test distance point; , Indicates the first The, the The distance from each test distance point to the magnetoelectric antenna under test; This represents the natural logarithm function.

[0012] This invention uses logarithmic difference to calculate the spatial attenuation gradient between adjacent test points. By using the ratio of the logarithmic difference of the magnetic field strength amplitude to the logarithmic difference of the distance, the complex power-law attenuation relationship is transformed into an intuitive linear slope index. This can more sensitively reflect the instantaneous attenuation exponent of the magnetic field changing with distance, thereby accurately capturing the subtle trend change from the dominant induction field to the radiation field, providing a reliable basis for subsequent signal separation.

[0013] Preferably, the radiation component weighting factor satisfies the expression:

[0014] ;

[0015] In the formula, Indicates the first The radiation component weighting factor for each test interval; Indicates the first Spatial decay gradient of each test interval; The theoretical decay rate representing the pure inductive field; The theoretical attenuation rate representing a pure radiation field; Indicates the sensitivity coefficient; Indicates the first tiny positive value; Represents the natural exponential function; Represents the absolute value symbol.

[0016] This invention utilizes the decay characteristics and sensitivity coefficient of the exponential function to intelligently filter signal components in different test intervals. When the decay gradient is close to the theoretical value of the pure induction field, the invalid data is automatically shielded. When the decay gradient is biased towards the radiation field characteristics, its weight is significantly increased. Thus, while retaining high-confidence radiation data, it effectively suppresses noise interference from the induction field, solving the problem that linear fitting algorithms have difficulty extracting submerged weak radiation features.

[0017] Preferably, the equivalent radiation source intensity satisfies the expression:

[0018] ;

[0019] In the formula, Indicates the equivalent radiation source intensity; This indicates the total number of test distance points; Indicates the first The radiation component weighting factor for each test interval; , Indicates the first The, the The magnetic field strength amplitude at each test distance point; , Indicates the first The, the The distance from each test distance point to the magnetoelectric antenna under test; This represents the second smallest positive value.

[0020] This invention constructs a difference equation containing a specific distance coefficient, utilizes the physical property that the induced field attenuates with the cube of the distance, and introduces the square ratio of the distance as a cancellation term to achieve reverse amplification and subtraction cancellation of the induced field components of adjacent measuring points. Combined with the statistical averaging of the weighting factor of the radiation component, the equivalent radiation source intensity containing only the radiation term is directly obtained, eliminating the interference of near-field reactive power on far-field performance derivation and ensuring the physical authenticity of the derivation results.

[0021] Preferably, the theoretical attenuation rate of the pure induction field The theoretical attenuation rate of the pure radiation field is 3; The value is 1.

[0022] Preferably, the deep near-field region satisfies the following conditions:

[0023] ;

[0024] in, This indicates the maximum distance from the test distance point to the magnetoelectric antenna under test. This represents the wavelength corresponding to the operating frequency of the magnetoelectric antenna under test. Represents pi; The symbol indicates that the value is much smaller than the given value.

[0025] Preferably, the step of acquiring the magnetic field strength amplitude at multiple test distance points within the deep near-field region of the magnetoelectric antenna under test includes:

[0026] The magnetoelectric antenna under test is fixed to the fixed end of the precision displacement slide;

[0027] A high-sensitivity magnetic field probe is installed on the moving end of the precision displacement slide, and the moving end is controlled to move along a preset path to obtain the magnetic field strength amplitude at each test distance point.

[0028] Preferably, the high-sensitivity magnetic field probe is a fluxgate sensor.

[0029] Preferably, obtaining the transmission performance of the magnetoelectric antenna based on the far-field effective magnetic field strength includes:

[0030] The ratio of the equivalent radiation source intensity to the set far-field distance is denoted as the far-field effective magnetic field intensity.

[0031] Calculate the radiated power corresponding to the effective far-field magnetic field strength;

[0032] Obtain the input power driving the magnetoelectric antenna under test;

[0033] The ratio of the radiated power to the input power is used as the transmission efficiency of the magnetoelectric antenna.

[0034] This invention further calculates the radiated power and radiation efficiency based on the derived far-field effective magnetic field strength, transforming the field strength data into an intuitive energy conversion index. By comparing the input power with the far-field effective radiated power, the true transmission performance of the magnetoelectric antenna in actual communication scenarios can be objectively evaluated, providing core performance parameters for antenna design optimization and engineering applications.

[0035] Secondly, the present invention provides a low-frequency transmission performance testing system for a magnetoelectric antenna, comprising a processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the aforementioned method for testing the low-frequency transmission performance of a magnetoelectric antenna is implemented.

[0036] By adopting the above technical solution, a computer program is generated from the above-mentioned method for testing the low-frequency transmission performance of a magnetoelectric antenna and stored in a memory so that it can be loaded and executed by a processor. This allows for the creation of a terminal device based on the memory and processor, making it convenient to use.

[0037] The beneficial effects of this invention are as follows:

[0038] (1) This invention transforms the complex power-law decay curve of field strength into an intuitive linear slope index through logarithmic difference operation, which can sensitively capture the trend of the magnetic field transitioning from the dominant field of induction to the dominant field of radiation, and provides an observation dimension for identifying radiation characteristics in the background of strong noise.

[0039] (2) The present invention constructs a difference model that includes the square ratio of distance, which can, at the mathematical processing level, use the induction field data of the nearby measuring point to back-derive and subtract the induction field component in the distant measuring point through a specific scaling factor, thereby eliminating the interference of the invalid energy storage field on the test results from the source.

[0040] (3) The present invention designs a nonlinear weighting function for attenuation gradient deviation, which can intelligently identify the purity of test data, automatically suppress invalid data weights whose attenuation characteristics conform to the law of the induction field, and at the same time amplify the data weights that present the attenuation characteristics of the radiation field. Through adaptive statistical averaging, the maximum likelihood estimation of the intensity of weak radiation sources is realized. Attached Figure Description

[0041] Figure 1 This is a flowchart illustrating a method for testing the low-frequency transmission performance of a magnetoelectric antenna according to the present invention;

[0042] Figure 2 This is a schematic diagram showing the distribution of deep near-field magnetic field intensity;

[0043] Figure 3 This is a schematic diagram showing the spatial attenuation gradient distribution of each test interval;

[0044] Figure 4 This is a schematic diagram showing the distribution of the weighting factors for the radiation components. Detailed Implementation

[0045] This invention discloses a method for testing the low-frequency transmission performance of a magnetoelectric antenna, referring to... Figure 1 This includes steps S1-S5:

[0046] S1: Deploy precision displacement and sensing equipment in an electromagnetic shielding room to create a low-noise near-field testing environment; control a high-sensitivity magnetic field probe to move along a preset path in the deep near-field region of the magnetoelectric antenna under test to obtain a sequence of test distance points that meet preset conditions.

[0047] It should be noted that low-frequency magnetoelectric antennas have a relatively long operating wavelength, for example... The corresponding wavelength is Conventional microwave anechoic chambers cannot provide the physical space required for far-field conditions. In the deep near-field region, the induced field component dominates, and its energy oscillates only near the antenna without radiating outwards. Directly measuring the field strength makes it impossible to distinguish between the induced field and the radiated field, leading to a severely inflated assessment of antenna transmission performance. Therefore, this invention first constructs a precise near-field scanning environment, providing a high signal-to-noise ratio physical basis for subsequently capturing subtle changes in the radiated field gradient.

[0048] Specifically, precision displacement and sensing equipment is deployed in an electromagnetically shielded room to create a low-noise near-field testing environment, including:

[0049] A test platform was built in an electromagnetic shielding room, and the magnetoelectric antenna under test was fixed to the fixed end of a non-magnetic precision displacement slide as a transmission source.

[0050] A high-sensitivity magnetic field probe is mounted on the moving end of the non-magnetic precision displacement slide. For example, a fluxgate sensor is used as the probe to ensure responsiveness to weak, low-frequency magnetic signals.

[0051] The system control program is set to control the high-sensitivity magnetic field probe to move along the axial or tangential path of the magnetoelectric antenna under test.

[0052] It should be noted that, in order to ensure that the measurement data is applicable to the subsequent near-field attenuation model, the sampling points need to be limited to the deep near-field range to avoid complex multipath effects.

[0053] Preferably, controlling the high-sensitivity magnetic field probe to move along a preset path within the deep near-field region of the magnetoelectric antenna under test to obtain a sequence of test distance points that meet preset conditions includes:

[0054] Select at least three different test distance points, and denote them as the test distance point sequence. .

[0055] All test distance points must meet the deep near-field condition:

[0056] ;

[0057] In the formula, This represents the distance from the 1st, 2nd to nth test distance points to the magnetoelectric antenna under test; This represents the wavelength corresponding to the operating frequency of the magnetoelectric antenna under test. Represents pi; Represents the maximum value function; The symbol indicates that the value is much smaller than the given value.

[0058] It should be noted that, as Figure 2 This is a deep near-field magnetic field intensity distribution map, used to visually demonstrate the data distribution characteristics and theoretical distribution laws of deep near-field tests of magnetoelectric antennas. The horizontal axis represents the test distance in meters, and the vertical axis represents the magnetic field intensity in amperes per meter. The solid line with circular markers represents the measured total magnetic field intensity curve, and the dashed line represents the theoretical induced field, which follows a cubic attenuation law curve based on distance.

[0059] Thus, a low-noise multi-point test environment was constructed and the test distance point sequence was established.

[0060] S2: Drive the magnetoelectric antenna under test to transmit a single-frequency signal and use a high-sensitivity magnetic field probe to collect the magnetic field strength amplitude at each test distance point; use the logarithmic difference method to process the magnetic field strength amplitude and distance data of adjacent test distance points to obtain the spatial attenuation gradient of each test interval formed by adjacent test distance points.

[0061] It should be noted that after acquiring the field strength data, it is necessary to analyze the attenuation characteristics of the magnetic field with distance. According to the electromagnetic wave propagation theory, the induced field component attenuates cubically with distance, while the radiated field component attenuates linearly with distance; these two exhibit significantly different rates of change in space. To transform this power-law attenuation relationship into a linear slope for easier differentiation, this invention introduces a logarithmic domain analysis method. By calculating the logarithmic rate of change of the field strength between adjacent measuring points, the composition of the magnetic field at the current location is determined.

[0062] Specifically, the magnetoelectric antenna under test is driven to transmit a single-frequency signal, and a high-sensitivity magnetic field probe is used to collect the magnetic field strength amplitude at each test distance point, including:

[0063] The signal generation module is used to drive the magnetoelectric antenna under test to transmit a single-frequency signal.

[0064] The high-sensitivity magnetic field probe is controlled to stop at each test distance point in sequence, and the corresponding magnetic field strength amplitude is collected to obtain the field strength data sequence corresponding to the test distance point sequence.

[0065] Two adjacent test distance points in the test distance point sequence are defined as a test interval. For n test distance points, a total of n-1 test intervals are formed.

[0066] It should be noted that, in order to intuitively characterize the rate of magnetic field decay, this invention constructs a spatial decay gradient index. Considering that the magnetic field strength amplitude is proportional to the negative power of the test distance, this invention uses a logarithmic form to process the magnetic field strength amplitude and distance data of adjacent test distance points to obtain the spatial decay gradient.

[0067] Preferably, the magnetic field strength amplitude and distance data of adjacent test distance points are processed using the logarithmic difference method to obtain the spatial attenuation gradient of each test interval formed by adjacent test distance points, including:

[0068] The spatial decay gradient of any test interval satisfies the expression:

[0069] ;

[0070] In the formula, Indicates the first Spatial decay gradient of each test interval; , Indicates the first The, the The magnetic field strength amplitude at each test distance point; , Indicates the first The, the The distance from each test distance point to the magnetoelectric antenna under test; This represents the natural logarithm function.

[0071] In the formula, Reflects the first The relative first The attenuation rate of the magnetic field strength amplitude at each test distance point; Reflects the first The relative first The relative range of the distance from each test distance point to the magnetoelectric antenna under test; The ratio of the attenuation magnitude of the magnetic field strength to the relative change span reflects the instantaneous attenuation exponent of the magnetic field strength as a function of distance. When the magnetic field strength is entirely dominated by a quasi-static induction field, this value approaches [value missing]. This is the cubic attenuation of distance; when an effective far-field radiation component exists, this value will be less than [a certain value]. and towards The approach directly reflects the physical process of the transition from the induced field to the radiated field in the scene.

[0072] It should be noted that, as Figure 3This diagram illustrates the spatial attenuation gradient distribution across different test intervals, showcasing the variation of the magnetic field spatial attenuation gradient in different test intervals within the deep near-field region of the magnetoelectric antenna. The horizontal axis represents the distance between the center of each interval (in meters), and the vertical axis represents the spatial attenuation gradient. The diagram includes the actual spatial attenuation gradient curves for each test interval, as well as theoretical attenuation rate benchmarks representing both the pure inductive and pure radiative fields.

[0073] At this point, the spatial decay gradient for each test interval has been obtained.

[0074] S3: Set theoretical attenuation rate benchmarks for pure induction field and pure radiation field, and construct a nonlinear weighting function in combination with preset sensitivity coefficient; based on the deviation of spatial attenuation gradient from the theoretical attenuation rate benchmark, use the nonlinear weighting function to obtain the radiation component weighting factor for each test interval.

[0075] It should be noted that the spatial attenuation gradient index only reflects the overall trend of the mixed field. However, in the deep near-field region, the radiation component is extremely weak and masked by the induced component, and directly using the gradient for linear calculation can easily introduce large errors. In order to accurately extract radiation characteristics, this invention constructs a nonlinear weighted evaluation system. Data points that conform to the attenuation characteristics of the induced field mainly contain ineffective energy and should be assigned lower weights; while data points that deviate from the characteristics of the induced field and show a radiation trend contain effective radiation information and should be assigned higher weights.

[0076] Specifically, theoretical attenuation rate benchmarks for the pure induction field and the pure radiation field are set, and a nonlinear weighting function is constructed by combining preset sensitivity coefficients, including:

[0077] Preset theoretical attenuation rates for pure induction field and pure radiation field. For example, the theoretical attenuation rate for pure induction field is... The theoretical attenuation rate of a pure radiation field is .

[0078] It should be noted that, in order to achieve the above nonlinear evaluation, this invention introduces a sensitivity coefficient to control the response speed of the weighting function to gradient changes. The sensitivity coefficient determines the sensitivity of the system to non-sensitive components.

[0079] Set the sensitivity coefficient, denoted as . For example, Set as .like If the value is too large, such as This can lead to an overly steep weighting function, exhibiting hard threshold characteristics, where only a very small number of data points that significantly deviate from the sensing field are retained, potentially resulting in the loss of weak radiation signals; if The value is too small, such as This will lead to a decrease in resolution, as the weighting factor will not be able to distinguish all data points effectively, and will not be able to effectively suppress induced field noise.

[0080] It should be noted that the core of constructing the radiation component weighting factor lies in constructing an inverse signal-to-noise ratio function. The theoretical attenuation rate of the pure induction field is regarded as the noise reference. By utilizing the attenuation characteristics of the exponential function, the output returns to zero when the input index is close to the noise reference; and the output increases when the input index deviates from the noise reference and moves closer to the signal target.

[0081] Preferably, based on the deviation of the spatial attenuation gradient index from the theoretical benchmark, the nonlinear weighting function is used to obtain the radiation component weighting factor for each test interval, including:

[0082] The weighting factor for radiation components satisfies the following expression:

[0083] ;

[0084] In the formula, Indicates the first The radiation component weighting factor for each test interval; Indicates the first Spatial decay gradient of each test interval; The theoretical decay rate representing the pure inductive field; The theoretical attenuation rate representing a pure radiation field; Indicates the sensitivity coefficient; This represents the first small positive value, used to prevent the denominator from being zero. Exemplary ; Represents the natural exponential function; Represents the absolute value symbol.

[0085] In the formula, Indicates the judgment ratio. When near When the sensing field dominates, molecules Approaching The judgment ratio approaches At this time, the exponent term , making , indicating the first Each test interval was identified as invalid noise and shielded; when Deviation and towards When molecules are close together and the radiation field is enhanced, Increase, denominator As the index decreases, the determination ratio increases, and the exponential term... Approaching , making Approaching , indicating the first The test intervals have high confidence levels, thus enabling adaptive extraction of the effective radiation components.

[0086] It should be noted that, as Figure 4 This is a distribution plot of the radiation component weighting factors, used to illustrate the distribution law of the radiation component weighting factors constructed based on the spatial attenuation gradient bias. The horizontal axis represents the test interval index, and the vertical axis represents the radiation component weighting factors.

[0087] At this point, the radiation component weighting factor for each test interval has been obtained.

[0088] S4: Construct a field cancellation term based on the square ratio of the distances between adjacent test distance points, and combine it with the radiation component weighting factor to obtain the equivalent radiation source intensity containing only the radiation term.

[0089] It should be noted that the radiation component weighting factor reflects the reliability of data points in each test interval, but it does not separate the radiation term physical quantity. Near-field total magnetic field. It can be approximated as the superposition of radiation and induction terms. ,in The coefficients representing radiation field components that are inversely proportional to distance. The coefficients representing the induced field components are inversely proportional to the cube of the distance. This represents the distance from the test distance point to the magnetoelectric antenna under test. Therefore, this invention utilizes the differences in physical laws to decompose the total magnetic field. The radiation term becomes a constant after multiplying by the distance, while the induction term still decays with the square of the distance after multiplying by the distance. Therefore, a difference equation containing a specific distance coefficient is constructed so that the induction term is canceled out, thereby allowing the remaining radiation term to be obtained.

[0090] It should be noted that, in order to... The and the first To eliminate the induced field term from adjacent test distance points, the square ratio of the distances needs to be introduced as a cancellation coefficient. Because the ... Distance from each test distance point to the magnetoelectric antenna under test Greater than the Distance from each test distance point to the magnetoelectric antenna under test In the normalized space, the induction term decays with the square of the distance, therefore the first... The inductive component at a point is smaller and needs to be multiplied by a factor greater than 1. coefficient Only then can it be restored to the first Points of the same magnitude can be subtracted and canceled out.

[0091] Specifically, a sensing field cancellation term based on the square ratio of the distances between adjacent test distance points is constructed. Combined with the radiation component weighting factor, the equivalent radiation source intensity containing only the radiation term is obtained, including:

[0092] The equivalent radiation source intensity satisfies the expression:

[0093] ;

[0094] In the formula, Indicates the equivalent radiation source intensity; This indicates the total number of test distance points; Indicates the first The radiation component weighting factor for each test interval; , Indicates the first The, the The magnetic field strength amplitude at each test distance point; , Indicates the first The, the The distance from each test distance point to the magnetoelectric antenna under test; This indicates the second smallest positive value, used to prevent the denominator from being zero. Exemplary .

[0095] In the formula, It is the first The magnetic field strength amplitude at each test distance point is normalized to the distance product space; It is a cancellation coefficient constructed based on the inductive field characteristics that are inversely proportional to the cube of the distance, through... Construct a cancellation term, representing the term to be cancelled out. The inductive field component at point is amplified in reverse to the first... Subtracting the value from the preceding term at the specified level effectively removes the influence of the induced field component coefficients while retaining the radiation component coefficients. Simultaneously, weighted statistics using a radiation component weighting factor suppress noise interference.

[0096] At this point, the equivalent radiation source intensity was obtained.

[0097] S5: Using the inverse proportional attenuation model, the equivalent radiation source intensity is extrapolated to a preset far-field distance to obtain the effective magnetic field strength in the far field; combined with the input power of the magnetoelectric antenna under test and the effective magnetic field strength in the far field, the radiation efficiency is obtained, and the low-frequency transmission performance test of the magnetoelectric antenna is completed.

[0098] It should be noted that the equivalent radiation source intensity is essentially the pure radiation source characteristic stripped of the induced field. Since directly measured near-field data contains a large number of induced field components, i.e., reactive power, this energy does not participate in communication transmission. Directly using it to calculate efficiency would lead to artificially inflated results. This invention utilizes the equivalent radiation source intensity to extrapolate performance indicators to the far-field region, which is physically impossible to measure directly, thus realizing the inference from near-field measurement data to far-field performance indicators.

[0099] Specifically, the equivalent radiation source intensity is extrapolated to a preset far-field distance using an inverse proportional attenuation model to obtain the effective far-field magnetic field intensity, including:

[0100] Set the far-field distance. It should be noted that the far-field distance is typically chosen as the target communication distance in the actual application. For example, the far-field distance is 100m.

[0101] It should be noted that in the far-field region, electromagnetic waves propagate outward in the form of spherical waves, and their energy density decreases with the square of the distance, meaning the field strength decreases linearly with distance. Therefore, the effective field strength at that distance can be obtained by dividing the equivalent radiation source intensity by the distance.

[0102] The ratio of the equivalent radiation source intensity to the far-field distance is denoted as the effective magnetic field strength. It should be noted that the effective magnetic field strength is based on the energy conservation principle of spherical wave radiation; the field strength decreases linearly with distance. By utilizing the equivalent radiation source intensity stripped of the influence of the induced field, far-field behavior can be accurately predicted.

[0103] Preferably, by combining the input power and far-field effective magnetic field strength of the magnetoelectric antenna under test, the radiation efficiency is obtained, and the low-frequency transmission performance test of the magnetoelectric antenna is completed, including:

[0104] The input power driving the magnetoelectric antenna is obtained; the far-field radiated power is calculated based on the effective magnetic field strength, and the ratio of the far-field radiated power to the input power is denoted as the radiation efficiency. It should be noted that the radiation efficiency accurately reflects the actual transmission performance of the magnetoelectric antenna in real-world communication scenarios.

[0105] This completes the low-frequency transmission performance test of the magnetoelectric antenna.

[0106] This invention also discloses a low-frequency transmission performance testing system for a magnetoelectric antenna, comprising a processor and a memory. The memory stores computer program instructions, which, when executed by the processor, implement a low-frequency transmission performance testing method for a magnetoelectric antenna according to the present invention.

[0107] The system also includes other components well known to those skilled in the art, such as communication buses and communication interfaces, the settings and functions of which are known in the art and will not be described in detail here.

[0108] While this specification has shown and described numerous embodiments of the invention, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and essence of the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in the practice of this invention.

Claims

1. A method for testing the low-frequency transmission performance of a magnetoelectric antenna, characterized in that, include: Obtain the magnetic field strength amplitude at multiple test distance points within the deep near-field region of the magnetoelectric antenna under test; The test intervals are formed by adjacent test distance points, and the spatial attenuation gradient of each test interval is obtained. The spatial attenuation gradient is positively correlated with the logarithmic difference of the magnetic field strength amplitude in the corresponding test interval, and negatively correlated with the logarithmic difference of the distance. The weighting factor of the radiation component is obtained based on the deviation between the spatial attenuation gradient and the theoretical attenuation rate of the pure induction field. The weighting factor of the radiation component is positively correlated with the deviation. Construct a field cancellation term based on the square ratio of the distances between adjacent test distance points, and combine it with the radiation component weighting factor to obtain the equivalent radiation source intensity containing only the radiation term; The effective magnetic field strength in the far field is obtained by extrapolating the equivalent radiation source intensity to a set far field distance, and the transmission performance of the magnetoelectric antenna is obtained based on the effective magnetic field strength in the far field. The equivalent radiation source intensity satisfies the expression: ; Indicates the equivalent radiation source intensity; This indicates the total number of test distance points; Indicates the first The radiation component weighting factor for each test interval; , Indicates the first The, the The magnetic field strength amplitude at each test distance point; , Indicates the first The, the The distance from each test distance point to the magnetoelectric antenna under test; This represents the second smallest positive value.

2. The method for testing the low-frequency transmission performance of a magnetoelectric antenna according to claim 1, characterized in that, The spatial decay gradient satisfies the expression: ； In the formula, Indicates the first Spatial decay gradient of each test interval; , Indicates the first The, the The magnetic field strength amplitude at each test distance point; , Indicates the first The, the The distance from each test distance point to the magnetoelectric antenna under test; This represents the natural logarithm function.

3. The method for testing the low-frequency transmission performance of a magnetoelectric antenna according to claim 1, characterized in that, The weighting factor for the radiation components satisfies the expression: ； In the formula, Indicates the first The radiation component weighting factor for each test interval; Indicates the first Spatial decay gradient of each test interval; The theoretical decay rate representing the pure inductive field; The theoretical attenuation rate representing a pure radiation field; Indicates the sensitivity coefficient; Indicates the first tiny positive value; Represents the natural exponential function; Represents the absolute value symbol.

4. The method for testing the low-frequency transmission performance of a magnetoelectric antenna according to claim 3, characterized in that, The theoretical attenuation rate of the pure induction field The theoretical attenuation rate of the pure radiation field is 3; The value is 1.

5. The method for testing the low-frequency transmission performance of a magnetoelectric antenna according to claim 1, characterized in that, The deep near-field region satisfies the following condition: ； in, This indicates the maximum distance from the test distance point to the magnetoelectric antenna under test. This represents the wavelength corresponding to the operating frequency of the magnetoelectric antenna under test. Represents pi; The symbol indicates that the value is much smaller than the given value.

6. The method for testing the low-frequency transmission performance of a magnetoelectric antenna according to claim 1, characterized in that, The acquisition of the magnetic field strength amplitude at multiple test distance points within the deep near-field region of the magnetoelectric antenna under test includes: The magnetoelectric antenna to be tested is fixed to the fixed end of the precision displacement slide; A high-sensitivity magnetic field probe is installed on the moving end of a precision displacement slide, and the moving end is controlled to move along a preset path to obtain the magnetic field strength amplitude at each test distance point.

7. The method for testing the low-frequency transmission performance of a magnetoelectric antenna according to claim 6, characterized in that, The high-sensitivity magnetic field probe is a fluxgate sensor.

8. The method for testing the low-frequency transmission performance of a magnetoelectric antenna according to claim 1, characterized in that, The transmission performance of the magnetoelectric antenna based on the effective far-field magnetic field strength includes: The ratio of the equivalent radiation source intensity to the set far-field distance is denoted as the far-field effective magnetic field intensity. Calculate the radiated power corresponding to the effective magnetic field strength in the far field; Obtain the input power driving the magnetoelectric antenna under test; The ratio of radiated power to input power is used as the transmission efficiency of a magnetoelectric antenna.

9. A low-frequency transmission performance testing system for a magnetoelectric antenna, characterized in that, include: A processor and a memory, wherein the memory stores computer program instructions that, when executed by the processor, implement a method for testing the low-frequency transmission performance of a magnetoelectric antenna according to any one of claims 1-8.

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