Broadband electromagnetic radiation specific absorption rate SAR probe and measurement method thereof

Abstract

The invention discloses a broadband electromagnetic radiation specific absorption rate SAR probe and a measurement method thereof, and the probe comprises a nonlinear electric field detector at the front end of the probe and used for inducing an incident radio frequency electric field to generate radio frequency oscillation voltage; the nonlinear electric field detector comprises a voltage stabilizing diode; the low-pass filter is connected with the nonlinear electric field detector and is used for filtering high-frequency signals in the radio-frequency oscillation voltage; the broadband high-resistance transmission line is respectively connected with the low-pass filter and the broadband signal receiver and is used for transmitting the filtered radio frequency oscillation voltage to the broadband signal receiver; and the broadband signal receiver at the tail end of the probe is used for receiving the filtered radio frequency oscillation voltage and converting the filtered radio frequency oscillation voltage into an electromagnetic radiation specific absorption rate SAR. By adopting a novel probe circuit design scheme, the problem that visual and effective dose evaluation equipment is lacked in current human body electromagnetic exposure dose evaluation is solved.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic radiation measurement technology, and in particular to a broadband electromagnetic radiation specific absorptivity SAR probe and its measurement method. Background Technology

[0002] This section is intended to provide background or context for the embodiments of the invention set forth in the claims. The description herein is not an admission that it is prior art simply because it is included in this section.

[0003] From a health risk perspective, we are typically interested in how much electromagnetic field power is absorbed by biological tissues, as this is largely responsible for the aforementioned thermal effects. This is usually described as a function of the relevant dose. For example, electromagnetic fields can penetrate into the interior of tissues (therefore tissue depth needs to be considered), in which case it is usually described using the "specific absorptivity" (SAR), which is the absorbed power per unit mass (W kg⁻¹). Electromagnetic radiation exposure limits are generally defined in two categories. Limits that are closely related to physical quantities associated with the harmful health effects caused by radiofrequency are called "basic limits." Some of these are physical quantities exposed within the body that are not easily measured. Therefore, quantities that are easier to estimate are derived from the basic limits and are called "reference levels" to provide a more practical way to characterize the degree of compliance with guidelines.

[0004] The use of electric field probes for measuring human electromagnetic exposure dose is a practical method that complies with current standards. Assuming whole-body exposure to a uniform field distribution, dosimetric studies can yield reference levels for the E-field intensity, H-field intensity, and incident power density. However, since these reference levels are highly conservative in most exposure scenarios, cases often exceed these levels but do not exceed the corresponding basic limits. Therefore, accurate measurement of the basic human limit (body specific absorption rate SAR) requires more advanced measurement tools. In actual measurements, because electric field probes provide a human reference level, they cannot obtain the true basic human limit level. The human exposure dose and related limits obtained from the reference level are highly conservative. Furthermore, converting the electric field probe measurement results into human electromagnetic exposure specific absorption rate (SAR) requires further numerical calculations or simulations, making real-time human exposure dose detection in the field impossible.

[0005] Electromagnetic modeling and simulation is another way to obtain the level of human electromagnetic exposure. It's a process of describing and predicting the spatial location of the human body and the spatial distribution of the electromagnetic field through mathematical methods and computer simulation. Its calculation process is based on Maxwell's equations, which describe the fundamental laws of the electromagnetic field. Common methods for electromagnetic modeling and simulation include the Finite Element Method (FEM), the Method of Moments (MOM), the Finite-Difference Time-Domain (FDTD) method, and Physical Optics (PO), each used for different simulation scenarios. However, obtaining accurate results from electromagnetic simulation requires establishing precise electromagnetic radiation sources and human body models, or alternative models that conform to real-world results. Furthermore, the differences in mesh generation between different algorithms must be considered; the accuracy of the model, the mesh generation method, and the mesh fineness all significantly affect the simulation results. Additionally, electromagnetic simulation modeling for obtaining the specific absorption rate (SAR) of human electromagnetic exposure is not real-time and cannot achieve real-time detection of human exposure dose in the field. Summary of the Invention

[0006] This invention provides a broadband electromagnetic radiation specific absorption rate (SAR) probe to address the lack of intuitive and effective dose assessment equipment in current human electromagnetic exposure dose assessment. The probe includes:

[0007] The nonlinear electric field detector at the front end of the probe is used to induce the incident radio frequency electric field to generate a radio frequency oscillation voltage; the nonlinear electric field detector includes a Zener diode;

[0008] A low-pass filter connected to a nonlinear electric field detector is used to filter out high-frequency signals in the radio frequency oscillation voltage;

[0009] A wideband high-resistance transmission line, connected to a low-pass filter and a wideband signal receiver respectively, is used to transmit the filtered RF oscillation voltage to the wideband signal receiver.

[0010] The broadband signal receiver at the end of the probe is used to receive the filtered radio frequency oscillation voltage and convert the filtered radio frequency oscillation voltage into electromagnetic radiation specific absorption rate (SAR).

[0011] This invention also provides a broadband electromagnetic radiation specific absorption rate (SAR) probe measurement method for intuitively and effectively assessing human electromagnetic exposure dose. The method includes:

[0012] Place the broadband SAR probe in the electromagnetic field environment to be measured;

[0013] The incident radio frequency electric field is received by a nonlinear electric field detector at the front end of the probe, and a radio frequency oscillation voltage is induced across the Zener diode.

[0014] High-frequency signals in the radio frequency oscillation voltage are filtered out by a low-pass filter;

[0015] The filtered RF oscillation voltage is transmitted to the broadband signal receiver via a wideband, high-resistance transmission line.

[0016] The filtered radio frequency oscillation voltage is received by a broadband signal receiver and converted into SAR.

[0017] In this embodiment of the invention, a nonlinear electric field detector is provided at the front end of the probe to induce an incident radio frequency electric field and generate a radio frequency oscillation voltage. The nonlinear electric field detector includes a Zener diode. A low-pass filter connected to the nonlinear electric field detector is used to filter out high-frequency signals in the radio frequency oscillation voltage. A wideband high-resistance transmission line connected to the low-pass filter and a wideband signal receiver is used to transmit the filtered radio frequency oscillation voltage to the wideband signal receiver. A wideband signal receiver at the end of the probe is used to receive the filtered radio frequency oscillation voltage and convert it into electromagnetic radiation specific absorption rate (SAR). By adopting a novel probe circuit design, the problem of the lack of intuitive and effective dose assessment equipment in current human electromagnetic exposure dose assessment is solved. The wideband signal receiver at the end of the probe can quickly receive the radio frequency oscillation voltage and convert it into SAR, realizing real-time monitoring of electromagnetic radiation. The use of a wideband high-resistance transmission line to quickly transmit the filtered radio frequency oscillation voltage to the wideband signal receiver not only improves transmission efficiency but also reduces the amount of material used, which is conducive to probe miniaturization. This innovation focuses on miniaturization and real-time performance, which can help conduct on-site electromagnetic safety testing of the probe, reduce production and testing costs, and improve probe design efficiency. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0019] Figure 1 This is a schematic diagram of a broadband electromagnetic radiation ratio absorptivity SAR probe in an embodiment of the present invention;

[0020] Figure 2 This is a diagram showing the circuit board dimensions of the broadband electromagnetic radiation ratio SAR probe in an embodiment of the present invention.

[0021] Figure 3 This is a finished product image of the broadband electromagnetic radiation ratio absorptivity SAR probe in an embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of the measurement method of the broadband electromagnetic radiation specific absorptivity SAR probe in an embodiment of the present invention;

[0023] Figure 5 This is a flowchart illustrating the measurement of the broadband SAR probe in a GTEM according to an embodiment of the present invention;

[0024] Figure 6 This is a schematic diagram of the measurement device for a broadband electromagnetic radiation specific absorption rate (SAR) probe in an embodiment of the present invention.

[0025] Figure 7 This is a simplified circuit diagram of the diode / filter equivalent circuit of the broadband electromagnetic radiation ratio absorptivity SAR probe in this embodiment of the invention;

[0026] Figure 8 This is a comparison chart of the measured and simulated values ​​of the terminal voltage of the broadband electromagnetic radiation ratio SAR probe in this embodiment of the invention;

[0027] Figure 9 This is a graph showing the relationship between the terminal voltage and SAR value of the broadband electromagnetic radiation specific absorption rate SAR probe in an embodiment of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0029] The inventors considered that radio frequency electromagnetic fields are used in many modern devices, including mobile communication infrastructure, telephones, Wi-Fi, and Bluetooth. Besides neural stimulation, radio frequency electromagnetic fields can affect the human body through two main biological effects: changes in membrane permeability and temperature rise (thermolysis). Knowledge of the relationship between thermal effects and health is also important, even in literature independent of radio frequency electromagnetic fields. The vast majority of radio frequency electromagnetic field health studies have been conducted using exposures significantly below the threshold for adverse health effects, while studies on the threshold of adverse health effects through known interaction mechanisms are relatively few. Modern near-field probes should meet the following requirements: wide measurement range (1-10 GHz), stable frequency response (up to ±3 dB) within the defined frequency range, wide amplitude dynamic range, and isotropic response (especially for triaxial probes). Furthermore, the probe must be electrically small-scale, as it should not disturb the field distribution. Considering the above constraints, high-resistivity line electric field probes based on diode loads are a good choice. Due to their portability and excellent characteristics, they can be used for rapid, broadband electric field measurements.

[0030] This invention provides a broadband electromagnetic radiation specific absorptivity SAR probe to address the current lack of intuitive and effective dose assessment equipment for human electromagnetic exposure dose evaluation. Figure 1 This is a schematic diagram of a broadband electromagnetic radiation ratio absorptivity SAR probe in an embodiment of the present invention, as shown below. Figure 1 As shown, the broadband SAR probe may include:

[0031] The nonlinear electric field detector at the front end of the probe is used to induce the incident radio frequency electric field to generate a radio frequency oscillation voltage; the nonlinear electric field detector includes a Zener diode;

[0032] A low-pass filter connected to a nonlinear electric field detector is used to filter out high-frequency signals in the radio frequency oscillation voltage;

[0033] A wideband high-resistance transmission line, connected to a low-pass filter and a wideband signal receiver respectively, is used to transmit the filtered RF oscillation voltage to the wideband signal receiver.

[0034] The broadband signal receiver at the end of the probe is used to receive the filtered radio frequency oscillation voltage and convert the filtered radio frequency oscillation voltage into electromagnetic radiation specific absorption rate (SAR).

[0035] Depend on Figure 1 As shown in the diagram, the broadband SAR probe provided in this embodiment of the invention can be used to measure electromagnetic radiation specific absorption rate. By adopting a novel probe circuit design, it solves the problem of the lack of intuitive and effective dose assessment equipment in the current human electromagnetic exposure dose assessment. The broadband signal receiver at the end of the probe can quickly receive the radio frequency oscillation voltage and convert it into electromagnetic radiation specific absorption rate (SAR), realizing real-time monitoring of electromagnetic radiation. The use of a broadband high-resistance transmission line to quickly transmit the filtered radio frequency oscillation voltage to the broadband signal receiver not only improves the transmission efficiency but also reduces the amount of material used, which is conducive to the miniaturization of the probe. The innovation in miniaturization and real-time performance of the device can help with the on-site electromagnetic safety testing of the probe, thereby reducing production and testing costs and improving the efficiency of probe design.

[0036] In this embodiment of the invention, the nonlinear electric field detector at the probe tip includes a Zener diode, and the incident radio frequency electric field induces a radio frequency oscillation voltage U across the Zener diode. oc After the low-pass filter removes the high-frequency signal from the RF oscillation voltage, the wideband high-resistance transmission line transmits the filtered RF oscillation voltage to the wideband signal receiver, which then converts the filtered RF oscillation voltage into electromagnetic radiation specific absorption rate (SAR).

[0037] In one embodiment, a short dipole can be used as a broadband, high-resistance transmission line. This is because short dipole antennas have wide bandwidth characteristics, which can cover a wide range of electromagnetic wave frequencies, making them very suitable for measuring electromagnetic radiation intensity at different frequencies. At the same time, short dipole antennas are small in size, making them easy to integrate into SAR probes to achieve electromagnetic radiation measurement.

[0038] To better adapt the probe to various measurement needs and improve measurement accuracy and efficiency, wideband, high-resistance transmission lines can be printed on flexible thin-film circuit boards. For example, see... Figure 2 , Figure 2 This is a diagram showing the circuit board dimensions of a broadband electromagnetic radiation ratio SAR probe in an embodiment of the present invention.

[0039] In one embodiment, a Zener diode is soldered between wideband, high-resistance transmission lines. For example, see... Figure 3 , Figure 3 This is a finished product image of the broadband electromagnetic radiation specific absorption rate SAR probe in an embodiment of the present invention.

[0040] In one embodiment, the low-pass filter includes a wideband, high-resistance transmission line and a capacitor connected to the wideband, high-resistance transmission line. Since the low-pass filter only allows low-frequency signals to pass through, while attenuating or blocking high-frequency signals, its cutoff frequency f... c This is the highest frequency that the low-pass filter allows to pass; signals exceeding this frequency will be significantly attenuated. To filter out high-frequency signals in the RF oscillation voltage, for example, a wideband, high-resistance transmission line with a resistance of approximately 40MΩ and a capacitor with a capacitance of 10pF can be selected to ensure the cutoff frequency f. c =8kHz. Each lead of the broadband high-resistance transmission line achieves a high resistance of 20MΩ, and the two leads together constitute a total resistance of 40MΩ.

[0041] In one embodiment, the nonlinear electric field detector at the probe tip can be encased in an electromagnetically transparent material. This is because if the nonlinear electric field detector is directly exposed to the external environment, it may be affected by various electromagnetic interferences, leading to a decrease in measurement accuracy. Electromagnetically transparent materials have low absorption, low reflection, and low scattering characteristics for electromagnetic waves. Encasing the detector in an electromagnetically transparent material can effectively reduce these interferences and ensure the accuracy of the measurement results.

[0042] In one embodiment, in order to isolate the influence of external electromagnetic fields on the transmission and minimize the influence of the probe itself on external electromagnetic fields, a high-resistivity material is used to wrap the broadband high-resistivity transmission line.

[0043] In one embodiment, the broadband signal receiver at the probe tip can be encased in an electromagnetic shielding box. In complex electromagnetic environments, the receiver may be subject to interference from other electronic devices, leading to a decrease in measurement accuracy. Encasing the broadband signal receiver in an electromagnetic shielding box can effectively reduce these interferences and ensure the accuracy of the measurement results.

[0044] Based on the same inventive concept, embodiments of the present invention also provide a method for measuring broadband electromagnetic radiation specific absorption rate (SAR) probes, in order to solve the problem of the lack of intuitive and effective dose assessment equipment in current human electromagnetic exposure dose assessment. Figure 4 This is a schematic diagram of the measurement method of a broadband electromagnetic radiation specific absorption rate (SAR) probe in an embodiment of the present invention, as shown below. Figure 4 As shown, the measurement method includes:

[0045] Step 401: Place the broadband SAR probe in the electromagnetic field environment to be measured;

[0046] Step 402: Receive the incident radio frequency electric field through the nonlinear electric field detector at the front end of the probe, and induce a radio frequency oscillation voltage across the Zener diode;

[0047] Step 403: Filter out high-frequency signals in the radio frequency oscillation voltage using a low-pass filter;

[0048] Step 404: Transmit the filtered RF oscillation voltage to the broadband signal receiver via a broadband high-resistance transmission line;

[0049] Step 405: Receive the filtered RF oscillation voltage through a broadband signal receiver and convert the filtered RF oscillation voltage into SAR.

[0050] In one embodiment, the filtered RF oscillation voltage can be converted to SAR using the following formula:

[0051] P rec =A ef ·S (1)

[0052]

[0053] SAR t =K t (f)·E 2 (3)

[0054] Among them, P rec A is the power of the radio frequency oscillation voltage received by the broadband signal receiver. ef U is the effective area of ​​the RF oscillation voltage, S is the power density of the RF oscillation voltage, and U is the effective area of ​​the RF oscillation voltage. ocLet λ be the radio frequency oscillation voltage generated by the nonlinear electric field detector, E be the electric field strength of the incident radio frequency electric field, π be pi, D be the directivity coefficient obtained by the nonlinear electric field detector from simulations at different frequencies, and R be... A and R B These are the resistances of the two leads on a broadband high-resistance transmission line, respectively, SAR t K represents the electromagnetic radiation specific absorptivity (SAR). t (f) is a function relating the characteristic value of electromagnetic radiation specific absorptivity (SAR) to frequency.

[0055] In this embodiment of the invention, the measurement may further include: measuring the broadband SAR probe within a gigahertz transverse electromagnetic wave chamber (GTEM). The gigahertz transverse electromagnetic wave chamber (GTEM) is designed based on broadband high-resistance transmission line theory, employing an asymmetric rectangular structure to simulate free space and generating transverse electromagnetic waves within the chamber. Its working principle involves introducing high-frequency electromagnetic waves into its interior, then allowing these waves to reflect and propagate between the metal casing and the terminal load, thereby forming a stable electromagnetic field. This avoids the influence of external environmental factors on the test results, thus improving the accuracy of the test.

[0056] To achieve more accurate measurements, the SAR probe under test is pre-connected to a broadband signal receiver to receive SAR signals. Since the DC voltage is measured by the broadband signal receiver at the end of the probe, the input resistance of the broadband signal receiver must be high enough, that is, greater than GΩ, to obtain accurate results. Figure 5 This is a flowchart illustrating the measurement process of the broadband SAR probe in a GTEM according to an embodiment of the present invention. Figure 5 As shown, the steps for measuring the broadband SAR probe in GTEM are as follows:

[0057] Step 501: Generate the CW input signal using a wideband vector signal generator;

[0058] Step 502: The CW input signal is amplified by an RF power amplifier;

[0059] Step 503: Place an isotropic probe next to the broadband SAR probe.

[0060] For example, Figure 6 This is a schematic diagram of the measurement device for a broadband electromagnetic radiation specific absorption rate (SAR) probe in an embodiment of the present invention, as shown below. Figure 6As shown, in this example, the CW input signal of the GTEM chamber is generated by a broadband vector signal generator and amplified by an RF power amplifier. Meanwhile, the broadband SAR probe is placed as the device under test on a polystyrene foam base and installed inside the GTEM. Then, an isotropic probe is placed next to the broadband SAR probe. The isotropic probe is used to control the electric field near the broadband SAR probe.

[0061] In one embodiment, to avoid polarization loss, the broadband SAR probe is oriented parallel to the incident radio frequency electric field. This is because when the probe's polarization direction is aligned with the polarization direction of the incident radio frequency electric field, the probe can maximize signal reception, thereby reducing polarization loss. By placing the probe and the incident radio frequency electric field parallel, the probe can accurately respond to the incident radio frequency electric field, ensuring the accuracy and reliability of the measurement results.

[0062] To verify the applicability and effectiveness of the broadband electromagnetic radiation specific absorption rate (SAR) probe in this embodiment of the invention, the following example illustrates the verification of this method. In this example, simulation is first performed in SEMCAD X, and then NI Multisim is used to simulate each different frequency. The theoretical output DC voltage is calculated at each frequency. The simulation results are then compared with the actual measurement results of the broadband SAR probe in this embodiment of the invention. Under the condition of electric field E = 20V / m, the electrical parameters of the broadband high-resistance transmission line are input, and the simulation yields U. oc and R A Use NI Multisim to create the diode / filter equivalent circuit, incorporating all relevant parameters of the broadband SAR probe into the equivalent circuit model. For example, see... Figure 7 , Figure 7 This is a simplified circuit diagram of the diode / filter equivalent circuit of the broadband electromagnetic radiation ratio absorptivity SAR probe in this embodiment of the invention, wherein U oc R represents the root-mean-square open-circuit voltage of the dipole input terminal. A R B It is the resistance of a wideband, high-resistance transmission line, C A The filter capacitor, low-pass filter, and wideband high-resistance transmission line are omitted in the equivalent circuit because they should not affect the steady-state DC voltage of the output. (Based on SEMCADX simulation results and U...) oc The voltage and SAR values ​​were calculated. Measurements were performed using a GTEM chamber, with the incident electric field value kept constant at 20 V / m. The probe's frequency response was analyzed within the 1 GHz to 10 GHz frequency range. The DC voltage measured at the probe terminals showed a frequency variation within ±3 dB within the 10 GHz range, indicating a uniform frequency response for the DC voltage within this range. The measured voltage value was approximately 0.35 V, consistent with simulation results within the recommended operating range. For example, see... Figure 8 , Figure 8This is a comparison chart of the measured and simulated values ​​of the terminal voltage of the broadband electromagnetic radiation specific absorption rate SAR probe in an embodiment of the present invention.

[0063] Figure 9 This is a graph showing the relationship between the terminal voltage and SAR value of the broadband electromagnetic radiation specific absorption rate SAR probe in this embodiment of the invention. The voltage-SAR response of the probe terminal at different frequencies was measured for different tissues, and the results are as follows: Figure 9 The correspondence shown.

[0064] In summary, this invention employs a novel probe circuit design by incorporating a nonlinear electric field detector at the probe's front end to induce an incident radio frequency electric field and generate a radio frequency oscillation voltage. The nonlinear electric field detector includes a Zener diode. A low-pass filter connected to the nonlinear electric field detector filters out high-frequency signals from the radio frequency oscillation voltage. A wideband high-resistance transmission line, connected to both the low-pass filter and a wideband signal receiver, transmits the filtered radio frequency oscillation voltage to the wideband signal receiver. A wideband signal receiver at the probe's end receives the filtered radio frequency oscillation voltage and converts it into electromagnetic radiation specific absorption rate (SAR). This solution addresses the current lack of intuitive and effective dose assessment equipment for human electromagnetic exposure dose evaluation. The wideband signal receiver can quickly receive and process signals, converting the filtered RF oscillation voltage into electromagnetic radiation specific absorption rate (SAR) for real-time monitoring of electromagnetic radiation. The use of a wideband, high-resistance transmission line to transmit the filtered RF oscillation voltage to the wideband signal receiver not only improves transmission efficiency but also reduces material usage, contributing to probe miniaturization. This innovative approach, focusing on both miniaturization and real-time performance, facilitates on-site electromagnetic safety testing of probes, reducing production and testing costs and improving probe design efficiency.

[0065] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0066] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0067] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0068] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0069] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A broadband electromagnetic radiation specific absorptivity SAR probe, characterized in that, include: A nonlinear electric field detector at the front end of the probe is used to induce the incident radio frequency electric field to generate a radio frequency oscillation voltage; The nonlinear electric field detector includes a Zener diode; A low-pass filter connected to a nonlinear electric field detector is used to filter out high-frequency signals in the radio frequency oscillation voltage; A wideband high-resistance transmission line, connected to a low-pass filter and a wideband signal receiver respectively, is used to transmit the filtered RF oscillation voltage to the wideband signal receiver. The broadband signal receiver at the end of the probe is used to receive the filtered radio frequency oscillation voltage and convert the filtered radio frequency oscillation voltage into electromagnetic radiation specific absorption rate (SAR).

2. The broadband SAR probe as described in claim 1, characterized in that, Wideband high-resistance transmission lines include: short dipoles.

3. The broadband SAR probe as described in claim 1, characterized in that, Zener diodes are soldered between wideband, high-resistance transmission lines.

4. The broadband SAR probe as described in claim 1, characterized in that, A low-pass filter includes a wideband, high-resistance transmission line and a capacitor connected to the wideband, high-resistance transmission line.

5. The broadband SAR probe as described in claim 1, characterized in that, The nonlinear electric field detector at the front end of the probe is encased in an electromagnetically transparent material.

6. The broadband SAR probe as described in claim 1, characterized in that, Wideband high-resistance transmission lines are wrapped with high-resistance material.

7. The broadband SAR probe as described in claim 1, characterized in that, The broadband signal receiver at the end of the probe is enclosed in an electromagnetic shielding box.

8. A measurement method using a broadband SAR probe according to any one of claims 1 to 7, characterized in that, include: Place the broadband SAR probe in the electromagnetic field environment to be measured; The incident radio frequency electric field is received by a nonlinear electric field detector at the front end of the probe, and a radio frequency oscillation voltage is induced across the Zener diode. High-frequency signals in the radio frequency oscillation voltage are filtered out by a low-pass filter; The filtered RF oscillation voltage is transmitted to the broadband signal receiver via a wideband, high-resistance transmission line. The filtered radio frequency oscillation voltage is received by a broadband signal receiver and converted into SAR.

9. The measurement method as described in claim 8, characterized in that, The filtered RF oscillation voltage is converted to SAR using the following formula: P rec =A ef ·S SAR t K t (faith 2 Among them, P rec A is the power of the radio frequency oscillation voltage received by the broadband signal receiver. ef U is the effective area of ​​the RF oscillation voltage, S is the power density of the RF oscillation voltage, and U is the effective area of ​​the RF oscillation voltage. oc Let λ be the RF oscillation voltage induced by the incident RF electric field induced by the nonlinear electric field detector, E be the electric field strength of the incident RF electric field, π be pi, D be the directivity coefficient obtained by the nonlinear electric field detector at different frequencies, and R be the RF oscillation voltage induced by the incident RF electric field induced by the nonlinear electric field detector. A and R B These are the resistances of the two leads on a broadband high-resistance transmission line, respectively, SAR t K represents the electromagnetic radiation specific absorptivity (SAR). t (f) is a function relating the characteristic value of electromagnetic radiation specific absorptivity (SAR) to frequency.

10. The measurement method as described in claim 8, characterized in that, Also includes: The broadband SAR probe was measured in a gigahertz transverse electromagnetic wave chamber (GTEM).

11. The measurement method as described in claim 8, characterized in that, Measurements were performed on the broadband SAR probe in the GTEM, including: The CW input signal is generated by a wideband vector signal generator; The CW input signal is amplified by an RF power amplifier; An isotropic probe is placed next to the broadband SAR probe.

12. The measurement method as described in claim 11, characterized in that, Measurements performed on the broadband SAR probe in GTEM also include: The direction of the broadband SAR probe is parallel to the incident radio frequency electric field.

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