Biological electromagnetic protection method and system based on electromagnetic field space distribution regulation and control

Abstract

The invention discloses a biological electromagnetic protection method and system based on electromagnetic field space distribution regulation and control, and belongs to the technical field of radio frequency exposure control and electromagnetic compatibility. The method comprises the following steps: acquiring parameters of a radiation source, a target biological area and an ITO metamaterial wave absorber, and setting the layout position of the wave absorber as to-be-optimized parameters; a three-dimensional coupling electromagnetic field distribution model is established, and an optimization problem including wave absorber dissipation and source side performance constraint is established with the purposes of increasing the size of a continuous low-field area and reducing the local specific absorption rate peak value; solving to obtain open layout parameters and carrying out open layout of the unclosed shielding body; and finally, closed-loop verification is carried out through electromagnetic simulation and phantom measurement registration, and a low-field target area is determined to be formed. According to the invention, protection can be realized without depending on a closed continuous conductive shielding body.

Description

Technical Field

[0001] This invention relates to the fields of radio frequency exposure control and electromagnetic compatibility technology, specifically to a bioelectromagnetic protection method and system based on the spatial distribution regulation of electromagnetic fields. Background Technology

[0002] The 5.8 GHz band is widely used in short-range wireless communication, radio frequency identification (RFID), industrial sensing, weather radar, and other wireless devices. With the increasing number of devices operating in the 5.8 GHz band, the risks of electromagnetic interference (EMI) superposition and electromagnetic leakage are becoming increasingly prominent. On the one hand, signal crosstalk between different devices can lead to increased communication error rates and decreased sensing accuracy; on the other hand, high-frequency electromagnetic leakage can interfere with surrounding sensitive equipment and may cause information security and electromagnetic compatibility issues.

[0003] Traditional solutions that control exposure levels by reducing transmit power often lead to a decline in radiation performance and link quality; shielding with closed conductive shields significantly alters the impedance matching and radiation state of the radiation source. In recent years, metamaterial absorbers have emerged as an effective approach to solving electromagnetic problems in specific frequency bands due to their high designability, controllable frequency bands, thinness, and ease of integration.

[0004] However, existing 5.8 GHz metamaterial absorbers still have the following problems in application: insufficient absorption stability at wide incident angles; rigid structures are difficult to adapt to curved surfaces or installation inside device housings; they only emphasize absorption performance and lack joint design with source-side performance, structural dissipation boundaries and reduction of biological region exposure; and they lack an integrated method for continuous low-field region formation, hotspot suppression and simulation / measurement closed-loop verification. Summary of the Invention

[0005] The purpose of this invention is to provide a technical solution to address one of the aforementioned problems in the prior art. Specifically, this invention is achieved through the following technical solution: Bio-electromagnetic protection methods based on the spatial distribution regulation of electromagnetic fields include the following steps: S1. Obtain radiation source parameters, target biological region parameters, and material loss parameters, geometric dimensions, and number of layers of the ITO metamaterial absorber. Determine the allowable installation area. Use the local specific absorptivity as the target exposure characterization quantity. Divide the target biological region into multiple evaluation units with the same evaluation volume. Set at least one of the ITO metamaterial absorber's placement position, orientation, spacing, and coverage as the placement parameters to be optimized. S2. Establish a three-dimensional coupled electromagnetic field distribution model of the radiation source, the target biological region, and the ITO metamaterial absorber. Calculate the baseline value of the local specific absorptivity of each evaluation unit when the ITO metamaterial absorber is not deployed. Determine the preset exposure threshold of the corresponding evaluation unit based on the baseline value. Construct an optimization problem with the goal of increasing the volume of the continuous low-field region that meets the preset exposure threshold and reducing the peak value of the local specific absorptivity of each evaluation unit in the target biological region. The optimization problem should include at least one absorber dissipation constraint and one source-side performance constraint. S3. Solve for the layout parameters to be optimized, obtain the open layout parameters of the ITO metamaterial absorber and lay them out accordingly. The layout state corresponding to the open layout parameters is that the ITO metamaterial absorber does not form a closed continuous conductive shield surrounding the radiation source and the target biological region. S4. Perform electromagnetic simulation and phantom measurement on the deployed target biological area. Register the phantom measurement sampling unit with the same fixed evaluation volume as the evaluation unit with the simulation evaluation unit according to the shared coordinate system. Extract continuous low-field regions according to the preset evaluation unit connectivity rules. When there is a continuous low-field region with a volume not less than a preset volume threshold and the preset volume threshold is not less than the volume of a single evaluation unit, the continuous low-field region is composed of one or more adjacent evaluation units, and the local specific absorption rate of each evaluation unit in the continuous low-field region is not higher than the preset exposure threshold of the corresponding evaluation unit, the peak value of the local specific absorption rate of each evaluation unit in the target biological area is not higher than the preset hotspot threshold, and all registered phantom measurement sampling units meet the preset deviation judgment conditions, including relative deviation conditions and absolute deviation conditions, a low-field target area is determined to be formed; otherwise, adjust the open deployment parameters and re-execute S1 to S4.

[0006] Furthermore, determining the preset exposure threshold for the corresponding evaluation unit based on the baseline value includes: Preset exposure threshold for corresponding evaluation unit Determine by the following formula: ; in, This represents the baseline value of the local specific absorptivity obtained for the k-th evaluation unit without the ITO metamaterial absorber. The absolute exposure limit is pre-set for the fixed evaluation volume. The preset decrease ratio, and .

[0007] Furthermore, the evaluation unit is formed by combining multiple adjacent simulated voxels, and each phantom measurement sampling unit corresponds one-to-one with a single evaluation unit.

[0008] Furthermore, the ITO metamaterial absorber comprises, from bottom to top, an ITO-PET reflective layer, a dielectric layer, and an etched ITO-PET pattern layer.

[0009] Furthermore, the ITO-PET reflective layer is a low sheet resistance conductive layer, the etched ITO-PET pattern layer is a high sheet resistance conductive layer, the dielectric layer is located between the complete ITO-PET reflective layer and the etched ITO-PET pattern layer, and the etched ITO-PET pattern layer is compositely connected to the PET substrate through an adhesive layer.

[0010] Furthermore, the etched ITO-PET pattern layer includes periodically arranged pattern units, and the pattern units include a combination structure of square frames and circular patterns.

[0011] Furthermore, the open deployment parameters include: The ITO metamaterial absorber is deployed in at least one of the following regions: a local region between the radiation source and the target biological region, a local region on the side of the radiation source away from the target biological region, and a local region surrounding the target biological region. The orientation of the ITO metamaterial absorber relative to the polarization direction of the radiation source, the distance between the ITO metamaterial absorber and the radiation source, and the coverage area of ​​the ITO metamaterial absorber are determined.

[0012] Furthermore, the optimization problem also includes reducing the preset high quantile value of the local specific absorption rate of each evaluation unit within the target biological region; the preset evaluation unit connectivity rule is a preset adjacency connectivity rule; the local enhanced hotspot is an evaluation unit whose local specific absorption rate is higher than that of its adjacent evaluation units and higher than the preset hotspot threshold, and a set of evaluation units that are connected to the evaluation units according to the preset adjacency connectivity rule and whose local specific absorption rate is not lower than the preset hotspot threshold.

[0013] Furthermore, the source-side performance constraints include: The total radiated power of the radiation source is not less than a first performance threshold, the absolute value of the return loss of the radiation source is not less than a second performance threshold, and the radiative efficiency of the radiation source is not less than a third performance threshold; the dissipation constraints of the absorber include: the dissipation power density of the ITO metamaterial absorber is not higher than a first dissipation upper limit, the loss power of the ITO metamaterial absorber is not higher than a second dissipation upper limit, and the surface temperature rise of the ITO metamaterial absorber is not higher than a third dissipation upper limit; for the registered k-th phantom measurement sampling unit, when the local specific absorptivity of the corresponding simulation evaluation unit... Not lower than the preset lower limit When the simulation results and measurement results are compared, the relative deviation is calculated using the following formula: ; when Below the preset lower limit When using absolute deviation: ; Deviated from the preset absolute threshold The relative deviation is calculated by comparing the alternative.

[0014] The bioelectromagnetic protection system based on the spatial distribution regulation of electromagnetic fields, using the aforementioned bioelectromagnetic protection method based on the spatial distribution regulation of electromagnetic fields, includes: a parameter acquisition module, a modeling and problem construction module, a solution and deployment output module, a closed-loop verification and evaluation module, and a data processing module. The parameter acquisition module, modeling and problem construction module, solution and deployment output module, and closed-loop verification and evaluation module are respectively connected to the data processing module. The parameter acquisition module is used to acquire radiation source parameters, target biological region parameters, and material loss parameters, geometric dimensions, and number of layers of the ITO metamaterial absorber, determine the allowable installation area, use local specific absorptivity as the target exposure characterization quantity, divide the target biological region into multiple evaluation units with the same evaluation volume, and set at least one of the deployment position, orientation, spacing, and coverage of the ITO metamaterial absorber as the deployment parameters to be optimized. The modeling and problem construction module is used to establish a three-dimensional coupled electromagnetic field distribution model of the radiation source, the target biological region and the ITO metamaterial absorber, calculate the local specific absorptivity baseline value of each evaluation unit when the ITO metamaterial absorber is not deployed, determine the preset exposure threshold of the corresponding evaluation unit based on the baseline value, construct an optimization problem, with the goal of increasing the volume of the continuous low field region that meets the preset exposure threshold and reducing the peak value of the local specific absorptivity of each evaluation unit in the target biological region, and ensuring that the optimization problem includes at least one absorber dissipation constraint and one source-side performance constraint. The solution and deployment output module is used to solve the deployment parameters to be optimized, obtain the open deployment parameters of the ITO metamaterial absorber and output them to guide the physical deployment. The deployment state corresponding to the open deployment parameters is that the ITO metamaterial absorber does not form a closed continuous conductive shield surrounding the radiation source and the target biological region. The closed-loop verification and evaluation module is used to acquire electromagnetic simulation data and phantom measurement data of the target biological region after deployment according to the open deployment parameters, and to register the phantom measurement sampling unit with the same fixed evaluation volume as the evaluation unit with the simulation evaluation unit according to the shared coordinate system. It extracts continuous low-field regions according to preset evaluation unit connectivity rules. When there exists a continuous low-field region with a volume not less than a preset volume threshold and the preset volume threshold not less than the volume of a single evaluation unit, the continuous low-field region consists of one or more adjacent evaluation units, and the local specific absorption rate of each evaluation unit within the continuous low-field region is not higher than the preset exposure threshold of the corresponding evaluation unit, the peak value of the local specific absorption rate of each evaluation unit within the target biological region is not higher than a preset hotspot threshold, and all registered phantom measurement sampling units meet preset deviation judgment conditions including relative deviation conditions and absolute deviation conditions, a low-field target area is determined to be formed; otherwise, the open deployment parameters are adjusted.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: By coordinating the 5.8GHz coupling field distribution with an ITO metamaterial absorber and an open layout, protection can be achieved without relying on a closed continuous conductive shield. The core objective is to form a continuous low-field region, rather than simply reducing the peak value at a single point. At the same time, the dissipation state of the absorber and the source-side performance are constrained, making it more feasible for engineering. The results are improved in terms of measurability and reproducibility by relying on simulation and phantom measurement dual closed-loop verification. The ITO metamaterial absorber has the characteristics of flexibility, transparency, thinness and wide-angle absorption, making it suitable for installation on curved surfaces and inside equipment housings. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart illustrating a bioelectromagnetic protection method based on the spatial distribution regulation of electromagnetic fields. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The illustrative embodiments and descriptions of this invention are for illustrative purposes only and are not intended to limit the invention. It should be noted that this invention is already in the actual research and development stage.

[0018] Example 1 like Figure 1 As shown, the bioelectromagnetic protection method based on the spatial distribution regulation of electromagnetic fields includes the following steps: S1. Obtain radiation source parameters, target biological region parameters, and material loss parameters, geometric dimensions, and number of layers of the ITO metamaterial absorber. Determine the allowable installation area. Use the local specific absorptivity as the target exposure characterization quantity. Divide the target biological region into multiple evaluation units with the same evaluation volume. Set at least one of the ITO metamaterial absorber's placement position, orientation, spacing, and coverage as the placement parameters to be optimized. S2. Establish a three-dimensional coupled electromagnetic field distribution model of the radiation source, the target biological region, and the ITO metamaterial absorber. Calculate the baseline value of the local specific absorptivity of each evaluation unit when the ITO metamaterial absorber is not deployed. Determine the preset exposure threshold of the corresponding evaluation unit based on the baseline value. Construct an optimization problem with the goal of increasing the volume of the continuous low-field region that meets the preset exposure threshold and reducing the peak value of the local specific absorptivity of each evaluation unit in the target biological region. The optimization problem should include at least one absorber dissipation constraint and one source-side performance constraint. S3. Solve for the layout parameters to be optimized, obtain the open layout parameters of the ITO metamaterial absorber and lay them out accordingly. The layout state corresponding to the open layout parameters is that the ITO metamaterial absorber does not form a closed continuous conductive shield surrounding the radiation source and the target biological region. S4. Perform electromagnetic simulation and phantom measurement on the deployed target biological area. Register the phantom measurement sampling unit with the same fixed evaluation volume as the evaluation unit with the simulation evaluation unit according to the shared coordinate system. Extract continuous low-field regions according to the preset evaluation unit connectivity rules. When there is a continuous low-field region with a volume not less than a preset volume threshold and the preset volume threshold is not less than the volume of a single evaluation unit, the continuous low-field region is composed of one or more adjacent evaluation units, and the local specific absorption rate of each evaluation unit in the continuous low-field region is not higher than the preset exposure threshold of the corresponding evaluation unit, the peak value of the local specific absorption rate of each evaluation unit in the target biological area is not higher than the preset hotspot threshold, and all registered phantom measurement sampling units meet the preset deviation judgment conditions, including relative deviation conditions and absolute deviation conditions, a low-field target area is determined to be formed; otherwise, adjust the open deployment parameters and re-execute S1 to S4.

[0019] The extraction of continuous low-field regions is based on the simulation evaluation results after the absorption body is deployed, and is determined by the connectivity of the evaluation units.

[0020] First, for each evaluation unit within the target biological region, determine its local specific uptake. Does it meet the preset exposure threshold of the corresponding evaluation unit? If satisfied If the condition is met, the evaluation unit is marked as a low-field evaluation unit; otherwise, it is marked as a non-low-field evaluation unit.

[0021] Secondly, the adjacency relationship of evaluation units is constructed according to the preset evaluation unit connectivity rules. The preset evaluation unit connectivity rules are preferably the six-adjacency rule, meaning that two evaluation units are considered connected when they share a face. Then, a connectivity component search is performed on all low-field evaluation units. Preferably, a depth-first search, breadth-first search, or disjoint-set data structure can be used to divide all low-field evaluation units interconnected according to the preset evaluation unit connectivity rules into several candidate low-field connected regions. .

[0022] For any candidate low-field connected region Let the number of evaluation units it contains be... The volume of a single evaluation unit is The volume of the candidate low-field connected region is... for: ; Subsequently, the volumes of each candidate low-field connected region were compared. With preset volume threshold When a candidate low-field connected region satisfies: ; The candidate low-field connected region is then determined as a continuous low-field region that meets the volume requirement. If multiple continuous low-field regions that meet the volume requirement exist, all regions that meet the condition can be taken as a set of continuous low-field regions; preferably, the continuous low-field region with the largest volume can also be selected as the target continuous low-field region.

[0023] After extracting the continuous low-field region, the peak value of the local specific absorbance of each evaluation unit within the target biological region is then judged. Only when the peak value of the local specific absorbance of each evaluation unit within the target biological region is not higher than the preset hotspot threshold, and all registered phantom measurement sampling units meet the preset deviation judgment conditions, is the low-field target region finally determined to be formed.

[0024] For the identification of local enhanced hotspots, a method symmetrical to the extraction of continuous low-field regions can be adopted. That is, first identify the evaluation units whose local specific absorption rate is higher than that of adjacent evaluation units and higher than the preset hotspot threshold, and then merge them into hotspot regions according to the preset evaluation unit connectivity rules. This is used to help judge the effect of the open deployment scheme on hotspot suppression.

[0025] Specifically, let the baseline value of the local specific absorptivity of the k-th evaluation unit when no absorber is installed be [value missing]. The corresponding evaluation unit has a preset exposure threshold. Determine by the following formula: ; in, The absolute exposure limit is preset for the fixed evaluation volume; The preset decrease ratio, and .

[0026] The evaluation volume is a fixed spatial volume used to calculate the local specific absorption rate and determine the threshold; the target biological region is divided into multiple evaluation units according to the fixed spatial volume, and the phantom measurement sampling unit and the evaluation unit use the same evaluation volume.

[0027] The preset exposure threshold for the corresponding evaluation unit is: the target control value of the evaluation unit cannot be higher than the preset absolute exposure limit, nor can it be higher than the local specific absorption rate value after decreasing by a preset ratio relative to the undeployed state.

[0028] The optimization objective adopts a hierarchical strategy: First, maximize the satisfaction of The volume of the continuous low-field region; secondly, among the candidate deployment schemes that meet the above conditions, the preset high quantile value of the local specific absorbance of each evaluation unit in the target biological region is reduced, preferably the 95th percentile value; thirdly, when the high quantile values ​​are the same, the peak value of the local specific absorbance of each evaluation unit in the target biological region is further reduced.

[0029] The dissipation constraints of the absorber include at least one of the following: the absorber dissipation power density is not higher than the first dissipation limit, the absorber loss power is not higher than the second dissipation limit, and the absorber surface temperature rise is not higher than the third dissipation limit.

[0030] The source-side performance constraints include at least one of the following: the total radiated power of the radiation source is not less than the first performance threshold, the absolute value of the return loss is not less than the second performance threshold, and the radiation efficiency is not less than the third performance threshold.

[0031] For the registered k-th phantom measurement sampling unit: When the local specific absorption rate of the corresponding simulation evaluation unit Not lower than the preset lower limit When the relative deviation is calculated, use the following formula: ; when When using absolute deviation: ; and the preset absolute deviation threshold Compare.

[0032] The preset deviation judgment condition is determined to be met only if all registered phantom measurement sampling units meet the following bi-branch condition: when hour, Not exceeding the preset relative deviation allowable value; when hour, Not higher than the preset absolute deviation threshold .

[0033] In this application, The absolute exposure limit is a pre-set value for a fixed evaluation volume, expressed in W / kg. It is a dimensionless proportionality parameter, and The preset volume threshold corresponds to the minimum effective volume of the continuous low-field region, and its value is not less than the volume of a single evaluation unit; the first performance threshold corresponds to the lower limit of total radiated power; the second performance threshold corresponds to the lower limit of the absolute value of return loss, in dB; the third performance threshold corresponds to the lower limit of radiation efficiency; the third dissipation upper limit corresponds to the upper limit of the surface temperature rise of the absorber, in °C. If the effective heat dissipation area of ​​the absorber is... The equivalent thermal resistance is Then the second dissipation limit can be Confirmed, first dissipation limit can be Sure; and The units are all W / kg.

[0034] First, establish a unified coordinate system O-XYZ. Use the radiation source installation reference plane as a reference to establish spatial coordinates. The target biological area and the absorber are both defined in this coordinate system in terms of position and attitude.

[0035] Subsequently, parameters of the radiation source, target biological region, and absorber were acquired, and the permissible installation area was determined. Based on these parameters, a three-dimensional coupled electromagnetic field distribution model was established, and the baseline value of the local specific absorptivity of each evaluation unit was calculated when no absorber was installed.

[0036] Then, based on the threshold formula, a corresponding preset exposure threshold is generated for each evaluation unit, and multiple sets of candidate deployment parameter vectors to be optimized are generated within the allowed installation area: ; in, The coordinates of the reference point of the absorber are: The azimuth angle of the absorber relative to the polarization direction of the radiation source. The distance between the absorber and the radiation source. and These represent the coverage length and coverage width of the absorber, respectively.

[0037] The process of solving the layout parameters to be optimized includes the following steps: First, based on the permitted installation area, radiation source structural boundaries, the location relationship of the target biological area, and the minimum structural spacing requirements, the search range for each deployment parameter to be optimized is determined, forming candidate sets for location, orientation, spacing, and coverage. If multiple permitted installation areas exist, the union of the candidate locations corresponding to these multiple permitted installation areas is taken as the location search domain.

[0038] Secondly, the deployment parameters to be optimized are discretized within each search range according to a preset step size to form an initial set of candidate deployment schemes. For any candidate solution The deployment state of the ITO metamaterial absorber corresponding to the candidate scheme is substituted into the three-dimensional coupled electromagnetic field distribution model of the radiation source, the target biological region and the ITO metamaterial absorber.

[0039] Then, for any candidate scheme Calculate the following objective and constraint quantities: satisfying continuous low-field region volume Preset high quantile values ​​of local specific uptake of each evaluation unit within the target biological region. Peak value of local specific uptake in each evaluation unit within the target biological region. Power dissipation density of the absorber ; Absorber power loss Temperature rise on the surface of the absorber Total radiant power of the radiation source Absolute value of radiation source return loss Radiation source efficiency .

[0040] The preset high quantile value is preferably the 95th percentile value. Subsequently, candidate solutions that meet the following conditions are included in the feasible solution set. : ; ; ; ; ; When further limiting performance degradation is required, the following can also be added: ; If feasible solution set If the result is empty, update the search range and distance of one or more deployment parameters to be optimized, regenerate the candidate deployment scheme set, and repeat the above steps.

[0041] In the set of feasible solutions In the selection process, the candidate scheme with the largest continuous low-field region volume is prioritized to form the first candidate set. : ; First Candidate Set In the next step, the candidate scheme with the smallest preset high quantile value is selected to form the second candidate set. : ; Second candidate set In the next step, the candidate scheme with the smallest local specific absorption rate peak value is selected as the target open deployment parameter. : ; Preferably, the target open deployment parameters are used. Centered on the target, the step size of the layout parameters to be optimized is reduced, and local candidate solutions are regenerated in its neighborhood. The aforementioned calculation of target and constraint quantities, screening of feasible solutions, and hierarchical optimization process are repeated to improve the solution accuracy. When the target open layout parameters no longer change after two consecutive local refinements, or when the step size of each parameter is reduced to the preset minimum step size, the refinement solution is stopped.

[0042] Finally, the target open deployment parameters are used as the basis for the deployment of ITO metamaterial microwave absorbers, and the open deployment of microwave absorbers within the allowable installation area is completed.

[0043] For each group The system calculates the local specific absorptivity distribution, continuous low-field region volume, preset high quantile value, peak value, absorber dissipation power density, absorber loss power, absorber surface temperature rise, total radiated power, absolute value of return loss, and radiative efficiency after deployment, and eliminates candidate schemes that do not meet the constraints. Among the retained schemes, the one with the largest continuous low-field region volume is selected first; if there are tied schemes, the one with the smaller preset high quantile value is selected; if they are still tied, the one with the smaller peak value is selected.

[0044] Finally, electromagnetic simulation and phantom measurements are performed on the deployed target biological region, and the phantom measurement sampling units are registered with the simulation evaluation units according to a shared coordinate system. The current open deployment parameters are considered valid only when all registered phantom measurement sampling units meet the preset deviation judgment conditions and a continuous low-field region is established. If necessary, near-field electric field distribution near the target biological region can also be collected as auxiliary verification data to determine whether the hotspot locations are consistent with the simulation results and whether the field distribution change trend is consistent.

[0045] To ensure the comparability of simulation results with phantom measurement results, the phantom measurement sampling unit and the simulation evaluation unit use the same fixed evaluation volume and are registered in the same common coordinate system.

[0046] The shared coordinate system uses the radiation source installation reference plane, the target biological area reference plane, or the fixture positioning plane as a reference, and determines the origin and coordinate axis directions through at least three non-collinear reference points. These three non-collinear reference points can be identified in both the simulation model and the phantom measurement device.

[0047] Secondly, the spatial location of each evaluation unit is determined in the simulation model. For the first... Each evaluation unit records its center coordinates. The simulation evaluation results include the corresponding spatial boundary range and the local specific absorption rate corresponding to the evaluation unit. .

[0048] Then, during the phantom measurement process, a measurement coordinate system is established using reference points and reference directions consistent with the shared coordinate system. For each phantom measurement sampling unit, its center position and sampling volume range are recorded, and the center coordinates of the sampling unit in the measurement coordinate system are mapped to the shared coordinate system through rigid body transformation. The rigid body transformation includes translation and rotation transformations, the parameters of which are determined by the corresponding positions of the reference points in the simulation model and the measurement system.

[0049] After coordinate transformation, each phantom measurement sampling unit is mapped to a simulation evaluation unit. Preferably, when the phantom measurement sampling unit and the simulation evaluation unit use the same fixed evaluation volume and their center coordinates correspond one-to-one, they are directly regarded as corresponding units. If a single phantom measurement sampling unit overlaps with multiple simulation evaluation units due to installation errors, mesh discretization errors, or measurement positioning errors, the simulation evaluation unit with the largest overlap volume with the phantom measurement sampling unit is preferably selected as the corresponding evaluation unit.

[0050] After registration is completed, for the registered first... Individual phantom measurement sampling unit, recording phantom measurement results And according to the preset deviation judgment conditions and A comparison is made. The simulation results are considered consistent with the measurement results only if all registered phantom measurement sampling units meet the preset deviation judgment conditions.

[0051] In one specific embodiment, the ITO metamaterial absorber comprises, from bottom to top: a complete ITO-PET reflective layer, a PVC dielectric layer, and an etched ITO-PET patterned layer. The sheet resistance of the complete ITO-PET reflective layer is 6 Ω / sq, and the sheet resistance of the etched ITO-PET patterned layer is 180 Ω / sq. The PVC dielectric layer is 6 mm thick, the PET substrate is 0.175 mm thick, and the OCA adhesive layer is 50 μm thick.

[0052] Period of etched patterned layer The size is 12mm, and the pattern consists of a combination of square frames and circular patterns, with the square pattern measuring [size missing]. The line width of the pattern is 8mm. The radius of the circular pattern is 0.5mm. The thickness is 4mm. This structure achieves high absorption near the 5.8GHz center frequency and maintains stable absorption characteristics in both TE and TM polarization modes.

[0053] The common structural basis of the ITO metamaterial absorbers is: a complete ITO reflective layer provides the reflection boundary, a dielectric layer provides support and impedance adjustment, and an etched ITO patterned layer provides coupling and absorption modulation. Any ITO metamaterial absorber that meets this common structural basis and can achieve the target absorption characteristics near 5.8 GHz can be used as an implementation of the ITO metamaterial absorber in this application.

[0054] Example 2 The bioelectromagnetic protection system based on the spatial distribution regulation of electromagnetic fields, using the aforementioned bioelectromagnetic protection method based on the spatial distribution regulation of electromagnetic fields, includes: a parameter acquisition module, a modeling and problem construction module, a solution and deployment output module, a closed-loop verification and evaluation module, and a data processing module. The parameter acquisition module, modeling and problem construction module, solution and deployment output module, and closed-loop verification and evaluation module are respectively connected to the data processing module. The parameter acquisition module is used to acquire radiation source parameters, target biological region parameters, and material loss parameters, geometric dimensions, and number of layers of the ITO metamaterial absorber, determine the allowable installation area, use local specific absorptivity as the target exposure characterization quantity, divide the target biological region into multiple evaluation units with the same evaluation volume, and set at least one of the deployment position, orientation, spacing, and coverage of the ITO metamaterial absorber as the deployment parameters to be optimized. The modeling and problem construction module is used to establish a three-dimensional coupled electromagnetic field distribution model of the radiation source, the target biological region, and the ITO metamaterial absorber; calculate the baseline value of the local specific absorptivity of each evaluation unit when the ITO metamaterial absorber is not deployed; and determine the preset exposure threshold of the corresponding evaluation unit based on the baseline value; construct an optimization problem with the goal of increasing the volume of the continuous low-field region that meets the preset exposure threshold and reducing the peak value of the local specific absorptivity of each evaluation unit in the target biological region, and ensuring that the optimization problem includes at least one absorber dissipation constraint and one source-side performance constraint. The solution and deployment output module is used to solve the deployment parameters to be optimized, obtain the open deployment parameters of the ITO metamaterial absorber and output them to guide the physical deployment. The deployment state corresponding to the open deployment parameters is that the ITO metamaterial absorber does not form a closed continuous conductive shield surrounding the radiation source and the target biological region. The closed-loop verification and evaluation module is used to acquire electromagnetic simulation data and phantom measurement data of the target biological region after deployment according to the open deployment parameters, and to register the phantom measurement sampling unit with the same fixed evaluation volume as the evaluation unit with the simulation evaluation unit according to the shared coordinate system. It extracts continuous low-field regions according to preset evaluation unit connectivity rules. When there exists a continuous low-field region with a volume not less than a preset volume threshold and the preset volume threshold not less than the volume of a single evaluation unit, the continuous low-field region consists of one or more adjacent evaluation units, and the local specific absorption rate of each evaluation unit within the continuous low-field region is not higher than the preset exposure threshold of the corresponding evaluation unit, the peak value of the local specific absorption rate of each evaluation unit within the target biological region is not higher than a preset hotspot threshold, and all registered phantom measurement sampling units meet preset deviation judgment conditions including relative deviation conditions and absolute deviation conditions, a low-field target area is determined to be formed; otherwise, the open deployment parameters are adjusted.

[0055] Example 3 In this embodiment, the ITO metamaterial absorber used is preferably the multilayer ITO-PET / PVC composite structure described in Example 1.

[0056] The radiation source is a transmitting module with a working center frequency of 5.8 GHz, and the target biological area is the local tissue area of ​​the head facing the transmitting module. The absorber is set in the allowable installation area inside the transmitting module housing, and adopts an open layout, without forming a closed continuous conductive shield.

[0057] In this embodiment, the permissible installation area is first determined based on the space within the terminal housing. Then, multiple candidate deployment schemes are generated using the absorber's position, orientation, spacing, and coverage as optimization parameters. A three-dimensional coupled electromagnetic field distribution model is established for each candidate scheme to calculate the local specific absorptivity distribution, continuous low-field region volume, preset high quantile value, peak value, absorber dissipation power density, absorber loss power, absorber surface temperature rise, total radiated power, absolute value of return loss, and radiation efficiency after deployment.

[0058] Only candidate schemes that simultaneously satisfy both absorber dissipation constraints and source-side performance constraints are retained, and among the retained schemes, the one with the largest continuous low-field region volume is prioritized. If there are tied schemes, the one with the smaller preset high quantile value is further selected; if still tied, the one with the smaller peak value is selected. After screening, the candidate scheme that satisfies the requirement of having the largest continuous low-field region volume and the lowest local specific absorptivity peak value of each evaluation unit within the target biological region is selected as the target open deployment scheme, and the deployment of the ITO metamaterial absorber is completed according to this scheme.

[0059] In this embodiment, the effective heat dissipation area of ​​the absorber and equivalent thermal resistance This was obtained through thermal simulation calibration of the corresponding terminal structure. , and Seeking and After deployment, electromagnetic simulation and phantom measurements are performed on the target biological area, and the phantom measurement sampling units are registered with the simulation evaluation units according to a shared coordinate system. If all registered phantom measurement sampling units meet the preset deviation judgment conditions, and a continuous low-field region meeting the threshold conditions is formed within the target biological area, then the open deployment scheme is deemed effective.

[0060] Example 4 When the installation attitude of the radiation source changes, the distance between the target biological area and the radiation source changes, the installation position of the absorber changes, or the working center frequency drifts, the radiation source parameters, target biological area parameters, and absorber candidate parameters are reacquired, and the baseline calculation, preset exposure threshold generation, open deployment parameter search, joint constraint screening, phantom measurement verification, and low-field target area determination are re-executed to update the final open deployment parameters.

[0061] 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 description is only a specific embodiment of the present invention and is 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 bioelectromagnetic protection method based on the spatial distribution regulation of electromagnetic fields, characterized in that, Includes the following steps: S1. Obtain radiation source parameters, target biological region parameters, and material loss parameters, geometric dimensions, and number of layers of the ITO metamaterial absorber. Determine the allowable installation area. Use the local specific absorptivity as the target exposure characterization quantity. Divide the target biological region into multiple evaluation units with the same evaluation volume. Set at least one of the ITO metamaterial absorber's placement position, orientation, spacing, and coverage as the placement parameters to be optimized. S2. Establish a three-dimensional coupled electromagnetic field distribution model of the radiation source, the target biological area and the ITO metamaterial absorber, calculate the local specific absorptivity baseline value of each evaluation unit when the ITO metamaterial absorber is not deployed, and determine the preset exposure threshold of the corresponding evaluation unit based on the baseline value. An optimization problem is constructed with the goal of increasing the volume of a continuous low-field region that meets the preset exposure threshold and reducing the peak local specific absorption rate of each evaluation unit within the target biological region, and the optimization problem includes at least one absorber dissipation constraint and one source-side performance constraint. S3. Solve for the layout parameters to be optimized, obtain the open layout parameters of the ITO metamaterial absorber and lay them out. The layout state corresponding to the open layout parameters is that the ITO metamaterial absorber does not form a closed continuous conductive shield surrounding the radiation source and the target biological region. S4. Perform electromagnetic simulation and phantom measurement on the deployed target biological area. Register the phantom measurement sampling unit with the same fixed evaluation volume as the evaluation unit with the simulation evaluation unit according to the shared coordinate system. Extract continuous low-field regions according to the preset evaluation unit connectivity rules. When there is a continuous low-field region with a volume not less than a preset volume threshold and the preset volume threshold is not less than the volume of a single evaluation unit, the continuous low-field region is composed of one or more adjacent evaluation units, and the local specific absorption rate of each evaluation unit in the continuous low-field region is not higher than the preset exposure threshold of the corresponding evaluation unit, the peak value of the local specific absorption rate of each evaluation unit in the target biological area is not higher than the preset hotspot threshold, and all registered phantom measurement sampling units meet the preset deviation judgment conditions, including relative deviation conditions and absolute deviation conditions, a low-field target area is determined to be formed; otherwise, adjust the open deployment parameters and re-execute S1 to S4.

2. The bioelectromagnetic protection method based on electromagnetic field spatial distribution regulation according to claim 1, characterized in that, The step of determining the preset exposure threshold for the corresponding evaluation unit based on the baseline value includes: Preset exposure threshold for corresponding evaluation unit Determine by the following formula: ； in, This represents the baseline value of the local specific absorptivity obtained for the k-th evaluation unit without the ITO metamaterial absorber. The absolute exposure limit is pre-set for the fixed evaluation volume. The preset decrease ratio, and .

3. The bioelectromagnetic protection method based on the spatial distribution regulation of electromagnetic fields according to claim 1, characterized in that, The evaluation unit is formed by combining multiple adjacent simulated voxels, and each phantom measurement sampling unit corresponds one-to-one with a single evaluation unit.

4. The bioelectromagnetic protection method based on the spatial distribution regulation of electromagnetic fields according to claim 1, characterized in that, The ITO metamaterial absorber comprises, from bottom to top, an ITO-PET reflective layer, a dielectric layer, and an etched ITO-PET pattern layer.

5. The bioelectromagnetic protection method based on the spatial distribution regulation of electromagnetic fields according to claim 4, characterized in that, The ITO-PET reflective layer is a low sheet resistance conductive layer, the etched ITO-PET pattern layer is a high sheet resistance conductive layer, the dielectric layer is located between the complete ITO-PET reflective layer and the etched ITO-PET pattern layer, and the etched ITO-PET pattern layer is compositely connected to the PET substrate through an adhesive layer.

6. The bioelectromagnetic protection method based on the spatial distribution regulation of electromagnetic fields according to claim 5, characterized in that, The etched ITO-PET patterned layer includes periodically arranged pattern units, and the pattern units include a combination structure of square frames and circular patterns.

7. The bioelectromagnetic protection method based on the spatial distribution regulation of electromagnetic fields according to claim 1, characterized in that, The open deployment parameters include: The ITO metamaterial absorber is deployed in at least one of the following regions: a local region between the radiation source and the target biological region, a local region on the side of the radiation source away from the target biological region, and a local region surrounding the target biological region. The orientation of the ITO metamaterial absorber relative to the polarization direction of the radiation source, the distance between the ITO metamaterial absorber and the radiation source, and the coverage area of ​​the ITO metamaterial absorber are determined.

8. The bioelectromagnetic protection method based on the spatial distribution regulation of electromagnetic fields according to claim 1, characterized in that, The optimization problem also includes reducing the preset high quantile value of the local specific absorption rate of each evaluation unit in the target biological region; the preset evaluation unit connectivity rule is a preset adjacency connectivity rule; the local enhanced hotspot is an evaluation unit whose local specific absorption rate is higher than that of the adjacent evaluation unit and higher than the preset hotspot threshold, and a set of evaluation units that are connected to the evaluation unit according to the preset adjacency connectivity rule and whose local specific absorption rate is not lower than the preset hotspot threshold.

9. The bioelectromagnetic protection method based on the spatial distribution regulation of electromagnetic fields according to claim 1, characterized in that, The source-side performance constraints include: The total radiated power of the radiation source is not less than a first performance threshold, the absolute value of the return loss of the radiation source is not less than a second performance threshold, and the radiative efficiency of the radiation source is not less than a third performance threshold; the dissipation constraints of the absorber include: the dissipation power density of the ITO metamaterial absorber is not higher than a first dissipation upper limit, the loss power of the ITO metamaterial absorber is not higher than a second dissipation upper limit, and the surface temperature rise of the ITO metamaterial absorber is not higher than a third dissipation upper limit; for the registered k-th phantom measurement sampling unit, when the local specific absorptivity of the corresponding simulation evaluation unit... Not lower than the preset lower limit When the simulation results and measurement results are compared, the relative deviation is calculated using the following formula: ； when Below the preset lower limit When using absolute deviation: ； Deviated from the preset absolute threshold The relative deviation is calculated by comparing the alternative.

10. A bioelectromagnetic protection system based on the spatial distribution regulation of electromagnetic fields, characterized in that, The bioelectromagnetic protection method based on the spatial distribution regulation of electromagnetic fields according to any one of claims 1-9 includes: a parameter acquisition module, a modeling and problem construction module, a solution and deployment output module, a closed-loop verification and evaluation module, and a data processing module; The parameter acquisition module, modeling and problem construction module, solution and deployment output module, and closed-loop verification and evaluation module are respectively connected to the data processing module. The parameter acquisition module is used to acquire radiation source parameters, target biological region parameters, and material loss parameters, geometric dimensions, and number of layers of the ITO metamaterial absorber, determine the allowable installation area, use local specific absorptivity as the target exposure characterization quantity, divide the target biological region into multiple evaluation units with the same evaluation volume, and set at least one of the deployment position, orientation, spacing, and coverage of the ITO metamaterial absorber as the deployment parameters to be optimized. The modeling and problem construction module is used to establish a three-dimensional coupled electromagnetic field distribution model of the radiation source, the target biological region and the ITO metamaterial absorber, calculate the local specific absorptivity baseline value of each evaluation unit when the ITO metamaterial absorber is not deployed, determine the preset exposure threshold of the corresponding evaluation unit based on the baseline value, construct an optimization problem, with the goal of increasing the volume of the continuous low field region that meets the preset exposure threshold and reducing the peak value of the local specific absorptivity of each evaluation unit in the target biological region, and ensuring that the optimization problem includes at least one absorber dissipation constraint and one source-side performance constraint. The solution and deployment output module is used to solve the deployment parameters to be optimized, obtain the open deployment parameters of the ITO metamaterial absorber and output them to guide the physical deployment. The deployment state corresponding to the open deployment parameters is that the ITO metamaterial absorber does not form a closed continuous conductive shield surrounding the radiation source and the target biological region. The closed-loop verification and evaluation module is used to acquire electromagnetic simulation data and phantom measurement data of the target biological region after deployment according to the open deployment parameters, and to register the phantom measurement sampling unit with the same fixed evaluation volume as the evaluation unit with the simulation evaluation unit according to the shared coordinate system. It extracts continuous low-field regions according to preset evaluation unit connectivity rules. When there exists a continuous low-field region with a volume not less than a preset volume threshold and the preset volume threshold not less than the volume of a single evaluation unit, the continuous low-field region consists of one or more adjacent evaluation units, and the local specific absorption rate of each evaluation unit within the continuous low-field region is not higher than the preset exposure threshold of the corresponding evaluation unit, the peak value of the local specific absorption rate of each evaluation unit within the target biological region is not higher than a preset hotspot threshold, and all registered phantom measurement sampling units meet preset deviation judgment conditions including relative deviation conditions and absolute deviation conditions, a low-field target area is determined to be formed; otherwise, the open deployment parameters are adjusted.

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