Detachable electric field probe and calibration method for measuring the specific absorptivity of a vehicle-mounted human body model

Abstract

This invention discloses a detachable electric field probe and calibration method for measuring the specific absorptivity of a vehicle-mounted human body model. The probe includes a metal dipole, a polytetrafluoroethylene (PTFE) ring, a waterproof metal casing, a ferrite magnetic ring, an SMA connector, and a detachable rubber sleeve. To prevent tissue fluid leakage, all components except the radiating element of the metal dipole are housed within the waterproof metal casing. The inner and outer conductors of the SMA connector connect to the upper and lower metal radiating elements, respectively. The ferrite magnetic ring is fitted onto the SMA connector, significantly improving the radiation pattern distortion problem of the electric field probe at low frequencies. The SMA connector connects to an RF receiver and a spectrum analyzer to acquire spectral information and the received power of the electric field probe, which, after calibration, reflects the magnitude of the field strength. This invention enables specific absorptivity measurement over a wide frequency range, featuring small size, low cost, and ease of use. It is suitable for specific absorptivity measurement in vehicle-mounted electromagnetic compatibility testing, medical device evaluation, and related scientific research fields.

Description

Technical Field

[0001] This invention relates to the field of specific absorptivity testing and measurement technology, specifically to a detachable electric field probe and calibration method for measuring the specific absorptivity of a vehicle-mounted human body model. Background Art

[0002] With the continuous development of modern society, biomedical engineering and wireless communication technologies are also evolving rapidly, and electronic products are becoming increasingly widespread, forming an indispensable part of people's daily lives. In recent years, the market share of electric vehicles has increased significantly, and these vehicles are equipped with a variety of electronic devices. These devices generally use radio frequency signals for information transmission.

[0003] Against this backdrop, in-vehicle specific absorption rate (SAR) measurement has become particularly important to ensure the safety and performance compliance of automotive electronic devices and protect the health of occupants. Currently, electric field probes used to measure SAR in electronic devices on the market generally suffer from high cost, complex structure, lack of portability, and inability to be used on real human models, limiting the application scope of in-vehicle SAR testing. Furthermore, traditional probes are typically one-piece designs, making disassembly difficult, which increases the difficulty of replacement and calibration, increases measurement costs, prolongs testing time, and reduces testing efficiency.

[0004] Therefore, there is an urgent need for an electric field probe suitable for vehicle-mounted human models to effectively solve the above problems and provide a more efficient and convenient solution for vehicle-mounted SAR testing. Summary of the Invention

[0005] The main objective of this invention is to provide a detachable electric field probe and calibration method for measuring the specific absorptivity of a vehicle-mounted human body model, which can achieve rapid disassembly and measurement on the vehicle-mounted human body model, and is inexpensive.

[0006] The present invention solves the above-mentioned technical problems by adopting the following technical solutions:

[0007] A detachable electric field probe for measuring the specific absorptivity of a vehicle-mounted human body model includes: a copper metal dipole, a polytetrafluoroethylene (PTFE) ring, a waterproof aluminum shell, a ferrite magnetic ring, an SMA connecting wire, and a detachable rubber sleeve. The copper metal dipole comprises two symmetrically arranged copper metal pillars and metal arms. The two copper metal pillars are respectively placed within holes in the waterproof aluminum shell on both sides. The copper metal arms are connected to the metal pillars, forming a symmetrical structure. The PTFE ring is fitted onto the copper metal pillars in the copper metal dipole to isolate the copper metal pillars from the waterproof aluminum shell, preventing short circuits. The inner and outer conductors of the SMA connecting wire are respectively welded to the bottoms of the copper metal pillars in the two symmetrical copper metal dipole portions. The ferrite magnetic ring is fitted onto the SMA connecting wire to optimize the low-frequency radiation pattern of the electric field probe.

[0008] Furthermore, the waterproof aluminum housing (3) includes a front cover, a rear cover, and upper and lower housing parts. The front and rear covers are fixed with screws, and the upper and lower housings adopt an upper and lower insertion structure, which can prevent water from entering the housing and causing a short circuit.

[0009] Furthermore, the detachable rubber sleeve (6) includes a silicone sleeve and a 3D printed bottle cap. The silicone sleeve is fixed to the waterproof aluminum shell (3), and the 3D printed bottle cap is used to fix the entire electric field probe to the human body model and to serve as a detachable component.

[0010] Furthermore, the waterproof aluminum shell has a length, width, and height of 60mm, 13mm, and 10mm respectively, and the front and rear covers are 1mm thick. The rear cover has a 3mm diameter hole for the SMA connecting wire (5) to pass through.

[0011] On the other hand, the present invention also discloses a calibration method for a detachable electric field probe for measuring the specific absorptivity of a vehicle-mounted human body model. Based on the aforementioned detachable electric field probe for measuring the specific absorptivity of a vehicle-mounted human body model, the method is characterized by including the following steps:

[0012] First, the dielectric parameters of the tissue fluid were measured using a vector network analyzer to obtain the attenuation constant within the tissue fluid. ;

[0013] Next, the three-antenna method was used to calculate the near-field strength of the three antennas. The antennas were fixed in the tissue fluid, and the three antennas were divided into three groups. Orthogonal tests were performed on each group. Using a guide rail, the antennas were slowly moved away from each other, and data was recorded for every 1mm of distance. The near-field strength of each group of antennas when they were directly opposite each other was recorded. , , And at the same time, record the current state of the three antennas. , , Then, use formulas (1), (2), and (3) to calculate the far-field strength of the antenna:

[0014]

[0015]

[0016]

[0017]

[0018]

[0019] in, , , These are the far-field gains of the three electric field probe antennas. , , These represent the reflection coefficients of electric field probes 1, 2, and 3, respectively. , , These represent the distance-dependent transmission coefficient functions for probes 1 and 2, probes 1 and 3, and probes 2 and 3, respectively. Represents the attenuation constant in a liquid. Represents the propagation constant in a liquid. Represents the distance between the two antennas. The wavelength in the liquid;

[0020] By simultaneously solving equations (1), (2), and (3), the results for the three power plant probes are obtained. , , Meanwhile, since the loss in the liquid is very large, the measurement is performed in the near field so that the near field gain can be regarded as a function of distance r. Therefore, the far field formula is extended to the near field region. Formula (6) is the extended far field gain formula, and formula (7) is the gain loss factor formula.

[0021]

[0022]

[0023] in, It is the far-field gain of the electric field probe. It is the distance between the antennas. This is the gain reduction factor; and It is a constant; obtained through least squares fitting. , , ;

[0024] get , , Then, the magnitude of the electric field strength at the fixed distance is calculated using formula (8):

[0025]

[0026] in, It refers to the magnitude of the input power. It is the antenna's reflection coefficient. It is the real part of the absolute value of the dielectric constant. It is the distance between the two antennas. Represents the attenuation constant in a liquid. It is the far-field gain of the electric field probe. It is the gain reduction factor;

[0027] After calculating the field strength, the ratio of the previously measured received power between each pair to the calculated field strength is used to obtain the calibration coefficient, which is then used to calibrate the electric field probe and obtain the electric field data at that location.

[0028] Furthermore, constant and It was obtained by fitting using the least squares method.

[0029] Furthermore, far-field gain Obtained by least squares fitting.

[0030] In another aspect, the present invention also discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of the method described above.

[0031] In another aspect, the present invention also discloses a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of the method described above.

[0032] As described above, this invention provides a detachable electric field probe for measuring the specific absorptivity of a vehicle-mounted human body model. The probe includes a metal dipole, a polytetrafluoroethylene (PTFE) ring, a waterproof metal shell, a ferrite magnetic ring, an SMA connecting wire, and a detachable rubber sleeve. To prevent tissue fluid leakage, all components except the radiating unit of the metal dipole are housed within the waterproof metal shell. The inner and outer conductors of the SMA connecting wire connect the upper and lower metal radiating units, respectively. The ferrite magnetic ring is fitted onto the SMA connecting wire, significantly improving the radiation pattern distortion problem of the electric field probe at low frequencies. The SMA connector connects to an RF receiver and a spectrum analyzer to acquire spectral information and the received power of the electric field probe. This value, after calibration, reflects the magnitude of the field strength. This invention enables specific absorptivity measurement over a wide frequency range and features small size, low cost, and ease of use. It is suitable for specific absorptivity measurement in vehicle-mounted electromagnetic compatibility testing, medical equipment evaluation, and related scientific research fields.

[0033] The small, detachable electric field probe for measuring the specific absorptivity of a vehicle-mounted human body model provided by this invention has significant advantages over other existing electric field probes for measuring specific absorptivity:

[0034] (1) Low cost. Compared with other complete absorption rate test probe systems that cost hundreds of thousands, this invention controls the cost of the electric field probe to a few hundred yuan, which greatly reduces the cost.

[0035] (2) It broadens the scope of specific absorption rate testing. Traditional electric field probes cannot achieve specific absorption rate testing of vehicle-mounted human models, while this invention broadens the testing scope.

[0036] (3) With the quick disassembly design, it can be quickly disassembled from the human body model to achieve rapid testing of the absorption rate of the vehicle-mounted human body model.

[0037] It should be understood that the descriptions in this section are not intended to identify key or essential features of embodiments of the invention, nor are they intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Of course, implementing any product of the invention does not necessarily require achieving all of the advantages described above simultaneously. Attached Figure Description

[0038] Figure 1 This is a three-dimensional structural diagram of the small detachable electric field probe with rubber sleeve removed according to an embodiment of the present invention;

[0039] Figure 2 This is a top view schematic diagram of the structure of the small detachable electric field probe with the rubber sleeve removed according to an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the main view of the small detachable electric field probe with the rubber sleeve removed, provided in an embodiment of the present invention.

[0041] Figure 4 This is a three-dimensional structural schematic diagram of the small detachable electric field probe provided in an embodiment of the present invention;

[0042] Figure 5 This is a top view of the structure of the small detachable electric field probe provided in an embodiment of the present invention;

[0043] Figure 6 This is a schematic diagram of the main structure of the small detachable electric field probe provided in an embodiment of the present invention;

[0044] Figure 7 This is a schematic diagram of the main structure of the small detachable electric field probe provided in an embodiment of the present invention;

[0045] Figure 8 This is a simulation diagram of the overall efficiency curve of the small detachable electric field probe provided in the embodiment of the present invention;

[0046] Figure 9 This is a comparison of the planar radiation patterns of the small detachable electric field probe provided in this embodiment of the invention at 600MHz, with and without a magnetic ring;

[0047] Figure 10 This is a comparison of the planar radiation patterns of the small detachable electric field probe provided in this embodiment of the invention at 800MHz, with and without a magnetic ring;

[0048] Figure 11 This is a comparison of the planar radiation patterns of the small detachable electric field probe provided in this embodiment of the invention at 1000MHz, without and with a magnetic ring.

[0049] Figure 12 This is a real-life photograph of the measurement of the dielectric constant of the liquid environment used by the small, detachable electric field probe provided in this embodiment of the invention.

[0050] Figure 13 These are actual photos of the calibration of the small, detachable electric field probe provided in an embodiment of the present invention.

[0051] Figure 14 This is a diagram showing the received power at various locations of the small, detachable electric field probe provided in this embodiment of the invention.

[0052] Figure 15 This is a diagram showing the electric field magnitude at various locations of the small, detachable electric field probe provided in this embodiment of the invention.

[0053] Figure 16 This is a calibration coefficient diagram of the small detachable electric field probe provided in an embodiment of the present invention. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] like Figure 1-6 As shown in the figure, a small, detachable electric field probe for measuring the specific absorption rate of a vehicle-mounted human body model according to an embodiment of the present invention includes: a copper metal dipole 1, a polytetrafluoroethylene ring 2, a waterproof aluminum shell 3, a ferrite magnetic ring 4, an SMA connecting wire 5, and a detachable rubber sleeve 6; the copper metal dipole 1 includes two symmetrically arranged copper metal pillars and metal arms, the two copper metal pillars are respectively placed in the holes of the waterproof aluminum shell 3 on both sides, and the copper metal arms are connected to the metal pillars to form a symmetrical structure; the polytetrafluoroethylene ring 2 is sleeved on the copper metal pillars in the copper metal dipole 2 to block the copper metal pillars and the waterproof aluminum shell 3 and prevent short circuit; the inner and outer conductors of the SMA connecting wire 5 are respectively welded to the bottom of the copper metal pillars in the two symmetrical copper metal dipole parts 1, and the ferrite magnetic ring 3 is sleeved on the connecting wire to optimize the low-frequency radiation pattern of the electric field probe.

[0056] Specifically, in this embodiment, the copper metal dipole 1 is divided into upper and lower parts. The upper part is a trapezoid made of copper with two arm-shaped metal parts. The conductivity of copper is 56.0 MS / m. The lengths of the long and short sides of the trapezoid are 24 mm and 6 mm, respectively. The lengths and widths of the two arms are 9.6 mm and 2.4 mm, respectively, and the metal thickness is 2 mm. The lower part is a copper metal cylinder with a diameter of 6 mm. Two identical structures form a pair of dipoles. A polytetrafluoroethylene (PTFE) ring 2 is fitted onto the copper metal cylinder below the copper metal dipole 1, serving as insulation to prevent the internal antenna part from directly contacting the metal outer shell. The inner and outer diameters of the PTFE ring 2 are 6 mm and 8.4 mm, respectively. The inner and outer conductors of the SMA connector 5 are soldered to the bottom of the copper pillars in the two symmetrical copper dipoles 1 to receive radio frequency signals. The ferrite magnetic ring 3 is fitted onto the RG316 radio frequency connector with a diameter of 2.5mm. This radio frequency connector is mainly used for the transmission of radio frequency signals from 0 to 6GHz, which is in line with all frequencies included in the design. At the same time, the ferrite magnetic ring 3 further optimizes the low-frequency radiation pattern of the electric field probe.

[0057] The waterproof aluminum housing 3 consists of four parts: a front cover, a rear cover, and upper and lower housings. The front and rear covers are fixed with screws, and the upper and lower housings adopt an interlocking structure to effectively prevent water from entering the housing and causing short circuits. The entire housing is made of aluminum. There is a 3mm diameter hole on the rear cover, which is mainly used for the RG316 RF connection cable. There is an 8.4mm hole at the front of each of the upper and lower housings, which is used to fix the lower ring part of the copper metal dipole 1.

[0058] like Figure 4-7 As shown in the figure, the small, detachable electric field probe for measuring the specific absorptivity of a vehicle-mounted human body model in this embodiment has a detachable rubber sleeve 6 added to the probe body to achieve detachability. This structure consists of two parts: the rubber sleeve and a 3D-printed bottle cap. The rubber sleeve prevents leakage of tissue fluid from inside the human body model, and due to its arbitrarily stretchable and deformable properties, it can control the expansion and contraction of the electric field probe within the human body model to measure the specific absorptivity values ​​at various depths. The 3D-printed bottle cap helps to fix the entire electric field probe at the required measurement position on the model. The specific effect of the bottle cap fixing connection is shown in the figure. Figure 7 As shown.

[0059] Since the electric field probe receives data in terms of power, it is necessary to convert the received power into electric field strength. This invention employs the following algorithm for power-field strength conversion, which is also used for calibration:

[0060] First, the dielectric parameters of the tissue fluid are measured using a vector network analyzer in order to obtain the attenuation constant within the tissue fluid. Specific test scenarios are as follows Figure 12 As shown.

[0061] Next, the three-antenna method was used to calculate the near-field strength of the three antennas. Specific test results are shown in the figure below. Figure 13 As shown, the antennas were fixed in the tissue fluid. The three antennas were divided into three groups, and each group underwent a direct-facing test. Using a guide rail, the antennas were slowly moved apart, and data was recorded for every 1mm of distance. The data for each of the three groups of antennas when they were directly facing each other were recorded. , , And at the same time, record the current state of the three antennas. , , Then, the far-field field strength of the antenna is calculated using formulas (1), (2), and (3) simultaneously:

[0062]

[0063]

[0064]

[0065]

[0066]

[0067] in, , , These are the far-field gains of the three electric field probe antennas. , , These represent the reflection coefficients of electric field probes 1, 2, and 3, respectively. , , These represent the distance-dependent transmission coefficient functions for probes 1 and 2, probes 1 and 3, and probes 2 and 3, respectively. Represents the attenuation constant in a liquid. Represents the propagation constant in a liquid. Represents the distance between the two antennas. The wavelength in the liquid.

[0068] By simultaneously solving equations (1), (2), and (3), the results of solving the three power plant probes were obtained. , , Meanwhile, since the loss in the liquid is very large, it should be measured in the near field so that the near field gain can be regarded as a function of distance r. Therefore, the far field formula is extended to the near field region. Formula (6) is the extended far field gain formula, and formula (7) is the gain loss factor formula.

[0069]

[0070]

[0071] in, It is the far-field gain of the electric field probe. This is the distance between the antennas. A constant. and This can be obtained by fitting using the least squares method. like Figure 14 As shown.

[0072] get , , The magnitude of the electric field strength at a fixed distance can then be calculated using formula (8):

[0073]

[0074] in, It refers to the magnitude of the input power. It is the antenna's reflection coefficient. It is the real part of the absolute value of the dielectric constant. It is the distance between the two antennas. Represents the attenuation constant in a liquid. It is the far-field gain of the electric field probe. It is the gain loss factor.

[0075] After calculating the field power, based on the previously measured power received between each pair of elements, such as... Figure 15 As shown, by comparing the electric field strength with the calculated field strength, a calibration coefficient can be obtained to calibrate the electric field probe and obtain the electric field data at that location.

[0076] The specific steps are summarized as follows:

[0077] (1) The dielectric properties of the tissue fluid were measured by a vector network analyzer and a coaxial probe method, and the attenuation constant was calculated. propagation constant .

[0078] (2) Using the three-antenna method and Friis's formula, the three antennas are paired up and tested head-on to obtain the results. , , We obtained three sets of data in units of distance.

[0079] (3) When When the distance is large enough, measure the three antennas respectively. , , .

[0080] (4) Fit the measured data to the formula (6), and then fit the result using the least squares method. , , .

[0081] (5) After obtaining the fitting results, the electric field at each position during calibration is obtained through the electric field formula.

[0082] (6) Compare the electric field at each location with the received power obtained in step (2) to obtain the calibration curve. The final calibration curve is shown in Figure 1. Figure 16 As shown.

[0083] The application effects of this invention will be described in detail below with reference to simulation.

[0084] Figure 8 A simulation graph of the overall efficiency curve of this invention is provided. It can be seen that the electric field probe of this invention achieves full-screen coverage from 30MHz to 6GHz, with an efficiency reaching up to 70% within the covered frequency band.

[0085] Figure 9-11 A comparison of the radiation patterns of the present invention under two different conditions is given: with and without the magnetic ring. Figure 9 The left side shows the radiation pattern with a magnetic ring, and the right side shows the radiation pattern without a magnetic ring, both at 600MHz. Figure 10 The left side shows the radiation pattern with a magnetic ring, and the right side shows the radiation pattern without a magnetic ring at 800MHz. Figure 11 The left side shows the radiation pattern with the magnetic ring, and the right side shows the radiation pattern without the magnetic ring, both at 1000MHz. It can be seen that adding the magnetic ring significantly improves the directivity of the radiation pattern compared to when the magnetic ring was not added, demonstrating the effectiveness of our improvement.

[0086] In summary, this invention presents a compact, detachable electric field probe for measuring the specific absorption rate (SAR) of a vehicle-mounted human body model. Based on practical testing and measurement environments, a redesigned and usable SAR measurement scheme has been developed, offering low cost and wide applicability for SAR testing of human bodies. The probe itself is very small (240mm*240mm), enabling SAR measurement within the 30MHz-6GHz range. Furthermore, the addition of a magnetic ring improves the probe's directivity, significantly enhancing its performance at low frequencies. This invention enables SAR measurement over a wide frequency range, featuring small size, low cost, and ease of use. It is suitable for SAR measurement in electromagnetic compatibility testing, medical device evaluation, and related research fields.

[0087] In another aspect, the present invention also discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of the method described above.

[0088] In another aspect, the present invention also discloses a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of the method described above.

[0089] In another embodiment provided in this application, a computer program product containing instructions is also provided, which, when run on a computer, causes the computer to execute any of the detachable electric field probes for measuring the specific absorptivity of an on-board human body model in the above embodiments.

[0090] It is understood that the system provided in the embodiments of the present invention corresponds to the method provided in the embodiments of the present invention, and the explanation, examples and beneficial effects of the relevant content can be referred to the corresponding parts of the above methods.

[0091] This application also provides an electronic device, including a processor, a communication interface, a memory, and a communication bus, wherein the processor, communication interface, and memory communicate with each other via the communication bus.

[0092] Memory, used to store computer programs;

[0093] The processor, when executing the program stored in the memory, implements the aforementioned detachable electric field probe for measuring the specific absorptivity of an onboard human body model.

[0094] The communication bus mentioned in the aforementioned electronic devices can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc.

[0095] The communication interface is used for communication between the aforementioned electronic devices and other devices.

[0096] The memory may include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0097] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0098] It should also be noted that electronic devices include terminal devices, which can also be called terminals, user equipment (UE), mobile stations (MS), mobile terminals (MT), etc. Terminal devices can be mobile phones, smart TVs, wearable devices, tablets, computers with wireless transceiver capabilities, virtual reality (VR) terminal devices, augmented reality (AR) terminal devices, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, and so on. The embodiments of this application do not limit the specific technologies or device forms used in the terminal devices.

[0099] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0100] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0101] Furthermore, it should be noted that if any directional indication (such as up, down, left, right, front, back, etc.) is involved in the embodiments of the present invention, the directional indication is only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0102] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, in the embodiments of this invention, "multiple" refers to two or more. Moreover, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

Claims

1. A detachable electric field probe for measuring the specific absorptivity of a vehicle-mounted human body model, characterized in that, include: Copper metal dipole (1), polytetrafluoroethylene ring (2), waterproof aluminum shell (3), ferrite magnetic ring (4), SMA connecting wire (5) and detachable rubber sleeve (6); The copper metal dipole (1) includes two symmetrically arranged copper metal pillars and copper metal arms. The two copper metal pillars are respectively placed in the holes of the waterproof aluminum shells (3) on both sides, and the copper metal arms are connected to the copper metal pillars. The polytetrafluoroethylene ring (2) is sleeved on the copper metal pillar in the copper metal dipole (1) to block the copper metal pillar and the waterproof aluminum shell (3) and prevent short circuit. The inner and outer conductors of the SMA connecting line (5) are respectively welded to the bottom of the copper metal pillars in the two symmetrical copper metal dipoles (1). The ferrite magnetic ring (4) is sleeved on the SMA connecting line (5) to optimize the low-frequency radiation pattern of the electric field probe.

2. The detachable electric field probe for measuring the specific absorptivity of a vehicle-mounted human body model as described in claim 1, characterized in that, The waterproof aluminum housing (3) includes a front cover, a rear cover, and upper and lower housing parts. The front and rear covers are fixed with screws, and the upper and lower housings adopt an upper and lower insertion structure, which can prevent water from entering the housing and causing a short circuit.

3. The detachable electric field probe for measuring the specific absorptivity of a vehicle-mounted human body model as described in claim 1, characterized in that, The detachable rubber sleeve (6) includes a silicone sleeve and a 3D printed bottle cap. The silicone sleeve is fixed to the waterproof aluminum shell (3), and the 3D printed bottle cap is used to fix the entire electric field probe to the human body model and to make it detachable.

4. The detachable electric field probe for measuring the specific absorptivity of a vehicle-mounted human body model as described in claim 1, characterized in that, The waterproof aluminum shell has a length, width, and height of 60mm, 13mm, and 10mm respectively, and the front and rear covers are 1mm thick. The rear cover has a 3mm diameter hole for the SMA connecting cable (5) to pass through.

5. A calibration method for a detachable electric field probe for measuring the specific absorptivity of a vehicle-mounted human model, based on the detachable electric field probe for measuring the specific absorptivity of a vehicle-mounted human model according to any one of claims 1-4, characterized in that, Includes the following steps, First, the dielectric parameters of the tissue fluid were measured using a vector network analyzer to obtain the attenuation constant within the tissue fluid. ; Next, the three-antenna method was used to calculate the near-field strength of the three antennas. The antennas were fixed in the tissue fluid, and the three antennas were divided into three groups. Orthogonal tests were performed on each group. Using a guide rail, the antennas were slowly moved away from each other, and data was recorded for every 1mm of distance. The near-field strength of each group of antennas when they were directly opposite each other was recorded. , , And at the same time, record the current state of the three antennas. , , Then, use formulas (1), (2), and (3) to calculate the far-field strength of the antenna: in, , , These are the far-field gains of the three electric field probe antennas. , , These represent the reflection coefficients of electric field probes 1, 2, and 3, respectively. , , These represent the distance-dependent transmission coefficient functions for probes 1 and 2, 1 and 3, and 2 and 3, respectively. Represents the attenuation constant in a liquid. Represents the propagation constant in a liquid. Represents the distance between the two antennas. The wavelength in the liquid; By simultaneously solving equations (1), (2), and (3), the results for the three power plant probes are obtained. , , Meanwhile, since the loss in the liquid is very large, the measurement is performed in the near field so that the near field gain can be regarded as a function of distance r. Therefore, the far field formula is extended to the near field region. Formula (6) is the extended far field gain formula, and formula (7) is the gain loss factor formula. in, It is the far-field gain of the electric field probe. It is the distance between the antennas. It is the gain reduction factor; and It is a constant; obtained by fitting using the least squares method. , and ; get , , Then, the magnitude of the electric field strength at the fixed distance is calculated using formula (8): in, It refers to the magnitude of the input power. It is the antenna's reflection coefficient. It is the real part of the absolute value of the dielectric constant. It is the distance between the two antennas. Represents the attenuation constant in a liquid. It is the far-field gain of the electric field probe. It is the gain reduction factor; After calculating the field strength, the ratio of the previously measured received power between each pair to the calculated field strength is used to obtain the calibration coefficient, which is then used to calibrate the electric field probe and obtain the electric field data at that location.

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