Planar interdigital electrode microwave sensor and heavy metal concentration detection system and method

Abstract

The invention discloses a planar interdigital electrode microwave sensor and a heavy metal concentration detection system and method, and relates to the technical field of heavy metal concentration detection. The heavy metal concentration detection method comprises the following steps: inserting a planar interdigital electrode microwave sensor into a container to obtain electromagnetic information of a traditional Chinese medicine decoction to be detected; the vector network analyzer converts the electromagnetic information into an S parameter; the computer calculates the representative value of the heavy metal concentration of the to-be-detected traditional Chinese medicine decoction according to the S parameter and a preset linear regression model; the computer compares the representative value of the heavy metal concentration with a preset limit value, if the representative value of the heavy metal concentration is larger than the preset limit value, a signal that the heavy metal concentration exceeds the standard is output, and otherwise, a signal that the heavy metal concentration is qualified is output. By adopting the planar interdigital electrode microwave sensor and the heavy metal concentration detection system and method, the problems of complex detection and high cost in the prior art can be solved, and real-time quick response and detection can be realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heavy metal concentration detection, and particularly relates to a planar interdigital electrode microwave sensor, a heavy metal concentration detection system and a method. BACKGROUND

[0002] The related detection methods in the industry can accurately detect the heavy metal concentration. However, there are still some problems: The ultraviolet-visible spectrophotometric method is interfered by many factors and has poor selectivity; the atomic fluorescence spectrophotometric method only has fluorescence effect on special metal ions and cannot detect all metal ions; the atomic absorption spectrometry cannot detect multiple heavy metal elements at the same time; the inductively coupled plasma mass spectrometry is easily polluted and the instrument is expensive, limiting its popular application; the complexing agent in the high performance liquid chromatography is limited, limiting its wide application in heavy metal concentration determination; the sample pre-treatment process in the electrochemical biosensor method is relatively complex and strict.

[0003] In addition, the above detection technologies also have the following problems: (1) the detection system is complex; (2) the detection cost is high; (3) the detection process is complex; (4) the whole detection cycle is time-consuming; (5) real-time rapid response and detection cannot be realized.

[0004] Microwave technology has the advantages of fast response and simple test system. However, according to the available documents and related reports, the microwave detection technology has not been applied to the detection of heavy metal concentration in traditional Chinese medicine decoction. This project intends to use microwave technology to realize the rapid detection of heavy metal concentration in traditional Chinese medicine decoction and realize the low-cost of the detection system. Therefore, it is urgent to design a planar interdigital electrode microwave sensor, a heavy metal concentration detection system and a method to solve the above problems. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a planar interdigital electrode microwave sensor, a heavy metal concentration detection system and a method, which can solve the problems of complex detection and high cost in the prior art, and can realize real-time rapid response and detection.

[0006] In order to solve the above technical problems, the present application provides a planar interdigital electrode microwave sensor, which comprises a dielectric substrate, an interdigital electrode arranged on the top surface of the dielectric substrate, a ground plane arranged on the bottom surface of the dielectric substrate and an adapter arranged on one end of the dielectric substrate, wherein the adapter is connected with the interdigital electrode; the interdigital electrode comprises two groups of coupled electrode groups, each electrode group comprises a power supply end, a bus bar and an electrode finger, the electrode finger is connected with the bus bar, and the electrode fingers of one electrode group are staggered with the electrode fingers of another electrode group; the length of the electrode finger is 8-12 times of the width of the electrode finger, and the distance between two adjacent electrode fingers is 1.4-3 times of the width of the electrode finger.

[0007] As the improvement of the above scheme, the electrode group comprises 6-10 electrode fingers; the finger length of the electrode fingers is 3.4-3.8 mm, the finger width is 0.3-0.5 mm, the finger distance of the adjacent two electrode fingers is 0.7-0.9 mm, and the surface of the interdigital electrode is plated with gold.

[0008] As the improvement of the above scheme, the medium substrate is an FR4 medium substrate.

[0009] Correspondingly, the application further discloses a heavy metal concentration detection system, which comprises a support, a container, a radio frequency coaxial line, a vector network analyzer, a computer and the planar interdigital electrode microwave sensor.

[0010] Correspondingly, the application further discloses a heavy metal concentration detection method based on the heavy metal concentration detection system, which comprises the following steps: inserting the planar interdigital electrode microwave sensor into the container to obtain electromagnetic information of the to-be-tested traditional Chinese medicine decoction; the vector network analyzer converts the electromagnetic information into S parameters; the computer calculates a heavy metal concentration representative value of the to-be-tested traditional Chinese medicine decoction according to the S parameters and a preset linear regression model; and the computer compares the heavy metal concentration representative value with a preset limit value, and outputs a heavy metal concentration exceeding standard signal if the heavy metal concentration representative value is greater than the preset limit value, or outputs a heavy metal concentration qualified signal.

[0011] As the improvement of the above scheme, the steps of constructing the linear regression model comprise the following steps: inserting the planar interdigital electrode microwave sensor into different containers to obtain reference electromagnetic information of reference traditional Chinese medicine decoctions with different concentrations; the vector network analyzer converts the reference electromagnetic information into reference S parameters; extracting reference S parameters corresponding to a calibration frequency point as calibration S parameters; and fitting the linear regression model according to absolute values of the calibration S parameters and heavy metal concentrations of the reference traditional Chinese medicine decoctions.

[0012] As the improvement of the above-mentioned scheme, the selecting step of the calibration frequency point comprises: traversing all reference frequency points in the preset frequency band; extracting the reference frequency point with the absolute value of the reference S parameter monotonously increasing with the reference traditional Chinese medicine decoction heavy metal concentration as a pre-selected frequency point; linearly fitting the absolute value of the reference S parameter of the pre-selected frequency point and the corresponding reference traditional Chinese medicine decoction heavy metal concentration; and selecting the pre-selected frequency point with the highest fitting degree as the calibration frequency point.

[0013] As the improvement of the above-mentioned scheme, the step of fitting the linear regression model according to the absolute value of the calibration S parameter and the reference traditional Chinese medicine decoction heavy metal concentration comprises: fitting the linear regression model by the least square method according to the absolute value of the calibration S parameter and the reference traditional Chinese medicine decoction heavy metal concentration.

[0014] As the improvement of the above-mentioned scheme, the formula of the linear regression model is:

[0015] Wherein, y is the absolute value of the calibration S parameter corresponding to the calibration frequency point, x is the heavy metal concentration representative value, k is the slope, and b is the intercept.

[0016] As the improvement of the above-mentioned scheme, the preset frequency band is 0GHz-8GHz, and the calibration frequency point is 0.44GHz.

[0017] The beneficial effects of the present application are: The plane interdigital electrode microwave sensor of the present application ensures the sensitivity of the plane interdigital electrode microwave sensor by optimizing the key parameters such as the finger length, finger width and finger distance of the electrode fingers, specifically by reducing the finger distance and moderately increasing the finger length to increase the equivalent capacitance change.

[0018] Further, the heavy metal concentration detection system of the present application utilizes the fast response advantage of microwave technology by using the plane interdigital electrode microwave sensor, connects the plane interdigital electrode microwave sensor, the radio frequency coaxial line, the vector network analyzer and the computer in sequence to build the heavy metal concentration detection system, which can solve the problem of high detection cost in the prior art and can realize real-time and rapid response and detection. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 Fig. 1 is a structural schematic diagram of the plane interdigital electrode microwave sensor of the present application; Figure 2 Fig. 2 is an electric field intensity distribution diagram of the plane interdigital electrode microwave sensor of the present application. Figure 3 It is a structural schematic diagram of the heavy metal concentration detection system of the traditional Chinese medicine decoction in the application; Figure 4 It is a flow chart of the heavy metal concentration detection method in the application; Figure 5 It is a flow chart of the construction of the linear regression model in the heavy metal concentration detection method in the application; Figure 6 It is an S parameter diagram of the planar interdigital electrode microwave sensor in the application for detecting the traditional Chinese medicine decoction with different concentrations of Pb at 0GHz-8GHz; Figure 7 It is an S parameter diagram of the planar interdigital electrode microwave sensor in the application for detecting the traditional Chinese medicine decoction with different concentrations of Pb at 0.4GHz-0.5GHz; Figure 8 It is a flow chart of the selection step of the calibration frequency point in the heavy metal concentration detection method in the application; Figure 9 It is a schematic diagram of the linear regression model fitting according to the absolute value of the calibration S parameter and the reference traditional Chinese medicine decoction heavy metal concentration in the heavy metal concentration detection method in the application. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the application more clear, the application will be further described in detail below with reference to the drawings. It is hereby declared that the up, down, left, right, front, back, inner and outer directions appearing or about to appear in the text of the application are based on the drawings of the application, and are not specific limitations on the application.

[0021] As shown in Figure 1 The planar interdigital electrode microwave sensor 100 in the application includes a dielectric substrate 11, an interdigital electrode 12 arranged on the top surface of the dielectric substrate 11, a ground plane 13 arranged on the bottom surface of the dielectric substrate 11, and an adapter 14 arranged at one end of the dielectric substrate 11, wherein the adapter 14 is connected with the interdigital electrode 12. The interdigital electrode 12 includes two groups of coupled electrode groups 121, each electrode group 121 includes a power supply end 122, a bus bar 123 and an electrode finger 124, the electrode finger 124 is connected with the bus bar 123, and the electrode fingers 124 of one electrode group 121 are staggered with the electrode fingers 124 of another electrode group 121. The length of the electrode finger 124 is 8-12 times of the width of the electrode finger 124, and the distance between two adjacent electrode fingers 124 is 1.4-3 times of the width of the electrode finger.

[0022] As shown in Figure 2As shown, it should be noted that the working principle of the planar interdigital electrode microwave sensor depends on the strong edge electric field generated by the electrode finger gap. When an external microwave signal is applied, the electric field is mainly distributed in the electrode finger gap and its surrounding area, so it is extremely sensitive to the measured material covered or infiltrated therein. The dielectric constant and loss factor of different materials will change the equivalent capacitance and resistance of the sensor, thereby causing changes in the impedance spectrum, resonance frequency or scattering parameters. By monitoring the response of these electrical properties, the sensor can realize the detection and quantitative analysis of gases, liquids or solids. The conductivity and heavy metal concentration of the traditional Chinese medicine decoction to be measured are related to the characteristics of the microwave signal.

[0023] Preferably, the length of the electrode finger 124 is 9 times the width of the electrode finger, and the distance between two adjacent electrode fingers 124 is 2 times the width of the electrode finger. This ratio can make the planar interdigital electrode microwave sensor have better sensitivity and more uniform electric field distribution in the frequency band of 0GHz-8GHz. The ratio of the length of the electrode finger 124 to the width of the electrode finger and the ratio of the distance between the electrode fingers to the width of the electrode finger have an important influence on the performance of the planar interdigital electrode microwave sensor 100: a proper ratio between the length of the electrode finger and the width of the electrode finger can balance the uniformity of the electric field distribution and the sensitivity. If the ratio of the length of the electrode finger to the width of the electrode finger is too high, the edge effect will interfere with the coupling electric field in the middle area, reducing the uniformity and sensitivity of the detection. If the ratio of the length of the electrode finger to the width of the electrode finger is too low, the coupling area is limited and the sensitivity is insufficient. A proper ratio between the distance between the electrode fingers and the width of the electrode finger can ensure that there is a proper electromagnetic coupling strength between adjacent electrode fingers 124. If the ratio is too high, the coupling field will weaken and the sensitivity will decrease. If the ratio is too low, parasitic effects are easy to occur and the electric field distribution is not uniform.

[0024] The planar interdigital electrode microwave sensor of the present application optimizes the length, width and distance of the electrode finger 124 to ensure the sensitivity of the planar interdigital electrode microwave sensor, specifically to reduce the distance and moderately increase the length to increase the equivalent capacitance change.

[0025] Preferably, the electrode group 121 includes 6-10 electrode fingers 124. The length of the electrode finger 124 is 3.4mm-3.8mm, the width of the electrode finger is 0.3mm-0.5mm, the distance between two adjacent electrode fingers 124 is 0.7mm-0.9mm, and the surface of the interdigital electrode 12 is gold-plated.

[0026] Specifically, each electrode group 121 includes 8 electrode fingers 124, the length of the electrode finger 124 is 3.6mm, the width of the electrode finger is 0.4mm, and the distance between two adjacent electrode fingers 124 is 0.8mm.

[0027] The medium substrate is an FR4 medium substrate. The FR4 medium substrate is pressed from a glass fiber cloth and an epoxy resin, has high mechanical strength and is not easy to deform, can provide stable support for the interdigital electrode, has a dielectric constant of about 4.0-4.7, has good frequency stability, and has low signal transmission loss, thereby guaranteeing performance.

[0028] The planar interdigital electrode microwave sensor further reduces the resistance of the interdigital electrode 12 by optimizing the number of electrode fingers 124 and adopting gold plating, and the medium substrate is selected as an FR4 medium substrate to improve stability.

[0029] The conductivity is the ability of a material to conduct current, and the change in the concentration of heavy metals in the to-be-measured traditional Chinese medicine decoction will affect the size of the solution conductivity. When the planar interdigital electrode microwave sensor is placed in the to-be-measured traditional Chinese medicine decoction, the reflected microwave signal changes with the change in the conductivity. Therefore, by studying the electromagnetic response, a specific change related to the to-be-measured traditional Chinese medicine decoction can be determined. The output of the planar interdigital electrode microwave sensor can be represented by S parameters. The amplitude response provided by the S parameters depends on the composition and concentration of heavy metals in the to-be-measured traditional Chinese medicine decoction.

[0030] As shown in Figure 3 Based on the above theory, the application also discloses a heavy metal concentration detection system 200, which comprises a support 21, a container 22, a radio frequency coaxial line 23, a vector network analyzer 24, a computer 25 and the above-mentioned planar interdigital electrode microwave sensor 100. The support 21 is used for placing the container 22, the container 22 is used for containing the to-be-measured traditional Chinese medicine decoction, and the planar interdigital electrode microwave sensor 100 is sequentially connected with the radio frequency coaxial line 23, the vector network analyzer 24 and the computer 25. The planar interdigital electrode microwave sensor 100 is used for collecting electromagnetic information of the to-be-measured traditional Chinese medicine decoction. The radio frequency coaxial line 23 is used for transmitting the electromagnetic information from the planar interdigital electrode microwave sensor 100 to the vector network analyzer 24. The vector network analyzer 24 is used for converting the electromagnetic information into S parameters. The computer 25 is used for calculating a representative value of the heavy metal concentration of the to-be-measured traditional Chinese medicine decoction according to the S parameters and judging whether the heavy metal concentration is over standard.

[0031] The heavy metal concentration detection system utilizes the fast response advantage of the microwave technology by the planar interdigital electrode microwave sensor 100, sequentially connects the planar interdigital electrode microwave sensor 100 with the radio frequency coaxial line 23, the vector network analyzer 24 and the computer 25 to construct the heavy metal concentration detection system, can solve the problems of high detection complexity and cost in the prior art, and can realize real-time and rapid response and detection.

[0032] In the structure of the heavy metal concentration detection system 200, the planar interdigital microwave sensor 100 is placed in the traditional Chinese medicine decoction to be measured, and the vector network analyzer 24 is connected with the computer 25. The vector network analyzer 24 displays corresponding S parameters on the screen according to the response of the planar interdigital microwave sensor 100 to the traditional Chinese medicine decoction to be measured. An interface algorithm is written to enable communication between the vector network analyzer 24 and the computer 25, and the computer 25 obtains original data from the vector network analyzer 24. A specific data processing algorithm is written to extract the required key parameters from the effective data, and to complete the analysis of the S parameter data of the traditional Chinese medicine decoction with different heavy metal concentrations. Finally, according to the measured concentration, the heavy metal concentration of the traditional Chinese medicine decoction is compared with the existing concentration standard, and it is output whether the heavy metal concentration of the traditional Chinese medicine decoction exceeds the standard.

[0033] As shown in Figure 4 Based on the above theory, the application also discloses a heavy metal concentration detection method based on the heavy metal concentration detection system. S1, the planar interdigital microwave sensor is inserted into the container to obtain electromagnetic information of the traditional Chinese medicine decoction to be measured; S2, the vector network analyzer converts the electromagnetic information into S parameters; S3, the computer calculates a heavy metal concentration representative value of the traditional Chinese medicine decoction to be measured according to the S parameters and a preset linear regression model; As shown in Figure 5 Specifically, the step of constructing the linear regression model comprises: S31, the planar interdigital microwave sensor is inserted into different containers to obtain reference electromagnetic information of reference traditional Chinese medicine decoctions with different concentrations; S32, the vector network analyzer converts the reference electromagnetic information into reference S parameters; S33, the reference S parameters corresponding to the calibration frequency point are extracted as calibration S parameters; As shown in Figure 6 and Figure 7 Because a large amount of data in the experiment is difficult to process manually, a specific algorithm needs to be designed to realize the collection and analysis of the test S parameters (the S parameters are S 11 Firstly, the planar interdigital microwave sensor is placed in the traditional Chinese medicine decoction (taking the heavy metal Pb concentration as an example), and the S 11 In the preset frequency range, multiple resonances will be generated, and the resonance depths of the traditional Chinese medicine decoctions with different heavy metal concentrations are different at these resonance frequency points. Therefore, the designed algorithm needs to select calibration frequency points with linear relationships from the multiple resonance frequency points. For example, the resonance depth (represented by S 11| The 0.44 GHz is a frequency point in line with the linear relationship as the heavy metal concentration increases. Preferably, the preset frequency range is 0-8 GHz, and the calibration frequency point is 0.44 GHz.

[0034] As shown in the specific selection of the calibration frequency point includes: Figure 8 S331, all reference frequency points in the preset frequency range are traversed; S332, the reference S parameter absolute value monotonically increasing with the reference traditional Chinese medicine decoction heavy metal concentration is extracted as a pre-selected frequency point; S333, the reference S parameter absolute value of the pre-selected frequency point and its corresponding reference traditional Chinese medicine decoction heavy metal concentration are linearly fitted; S334, the pre-selected frequency point with the highest goodness of fit is selected as the calibration frequency point.

[0035] S34, the linear regression model is fitted according to the absolute value of the calibration S parameter and the reference traditional Chinese medicine decoction heavy metal concentration.

[0036] As shown in the specific selection of the calibration frequency point includes: Figure 9 Preferably, the step of fitting the linear regression model according to the absolute value of the calibration S parameter and the reference traditional Chinese medicine decoction heavy metal concentration includes fitting the linear regression model by the least square method according to the absolute value of the calibration S parameter and the reference traditional Chinese medicine decoction heavy metal concentration.

[0037] Specifically, the formula of the linear regression model is:

[0038] Wherein, y is the absolute value of the calibration S parameter corresponding to the calibration frequency point, x is the heavy metal concentration representative value, k is the slope, and b is the intercept. The slope k, that is, the resonance depth change amount caused by the unit concentration change (the resonance depth change amount is embodied by the S parameter absolute value change), reflects the sensitivity of the sensor to the heavy metal concentration change; the intercept b, that is, the background resonance depth when the heavy metal concentration is zero, reflects the basic signal value of the sensor in the absence of heavy metals. The planar interdigital electrode microwave sensor selected by the present application has a slope k=0.0213 and an intercept b=0.1316.

[0039] S4, the computer compares the heavy metal concentration representative value with a preset limit value, if the heavy metal concentration representative value is greater than the preset limit value, a heavy metal concentration exceeding standard signal is output, otherwise, a heavy metal concentration qualified signal is output.

[0040] ​In summary, the planar interdigital electrode microwave sensor of the present application optimizes the key parameters such as the finger length, finger width and finger distance of the electrode fingers 124 to ensure the sensitivity of the planar interdigital electrode microwave sensor, specifically to reduce the finger distance and moderately increase the finger length to increase the equivalent capacitance change. The heavy metal concentration detection system of the present application uses the fast response advantage of the microwave technology by using the planar interdigital electrode microwave sensor 100, sequentially connects the planar interdigital electrode microwave sensor 100 with the radio frequency coaxial line 23, the vector network analyzer 24 and the computer 25, constructs the heavy metal concentration detection system, can solve the problem of high cost in the prior art detection, and can realize real-time and rapid response and detection. The heavy metal concentration detection method of the present application combines the vector network analyzer 24 with the linear regression model to construct a method for quickly and accurately detecting the heavy metal concentration of traditional Chinese medicine decoction, effectively solves the problems of long cycle, high cost and complex process of the traditional detection method, and realizes the efficiency and economy of detection.

[0041] The above is the preferred embodiment of the present application, and it should be pointed out that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements are also considered to be within the scope of protection of the present application.

Claims

1. A planar interdigital electrode microwave sensor, characterized in that, It includes a dielectric substrate, interdigitated electrodes disposed on the top surface of the dielectric substrate, a ground plane disposed on the bottom surface of the dielectric substrate, and an adapter disposed at one end of the dielectric substrate, wherein the adapter is connected to the interdigitated electrodes. The interdigitated electrode includes two coupled electrode groups. Each electrode group includes a power supply terminal, a bus bar, and electrode fingers. The electrode fingers are connected to the bus bar. The electrode fingers of one electrode group are arranged alternately with the electrode fingers of the other electrode group. The length of the electrode finger is 8-12 times the width of the finger, and the distance between two adjacent electrode fingers is 1.4-3 times the width of the electrode finger.

2. The planar interdigitated electrode microwave sensor according to claim 1, characterized in that, The electrode assembly includes 6-10 electrode fingers; The electrode fingers are 3.4mm-3.8mm long and 0.3mm-0.5mm wide, with a distance of 0.7mm-0.9mm between two adjacent electrode fingers, and the surface of the interdigitated electrodes is gold-plated.

3. The planar interdigitated electrode microwave sensor according to claim 1, characterized in that, The dielectric substrate is an FR4 dielectric substrate.

4. A heavy metal concentration detection system, characterized in that, The device includes a support, a container, an RF coaxial cable, a vector network analyzer, a computer, and a planar interdigitated electrode microwave sensor as described in any one of claims 1-3. The support is used to hold the container, which is used to hold the traditional Chinese medicine decoction to be tested. The planar interdigitated electrode microwave sensor is sequentially connected to the RF coaxial cable, the vector network analyzer, and the computer. The planar interdigitated electrode microwave sensor is used to collect the electromagnetic information of the Chinese herbal decoction to be tested; The radio frequency coaxial cable is used to transmit the electromagnetic information from the planar interdigitated electrode microwave sensor to the vector network analyzer; The vector network analyzer is used to convert the electromagnetic information into S-parameters; The computer is used to calculate the representative value of the heavy metal concentration of the Chinese herbal decoction to be tested based on the S parameters, and to determine whether the heavy metal concentration exceeds the standard.

5. A method for detecting heavy metal concentration based on the heavy metal concentration detection system of claim 4, characterized in that, include: The planar interdigitated electrode microwave sensor is inserted into the container to obtain the electromagnetic information of the Chinese herbal decoction to be tested; The vector network analyzer converts the electromagnetic information into S-parameters; The computer calculates the representative value of heavy metal concentration of the Chinese herbal decoction to be tested based on the S parameters and a preset linear regression model. The computer compares the representative value of the heavy metal concentration with a preset limit. If the representative value of the heavy metal concentration is greater than the preset limit, it outputs a heavy metal concentration exceeding the standard signal; otherwise, it outputs a heavy metal concentration qualified signal.

6. The method for detecting heavy metal concentration according to claim 5, characterized in that, The steps for constructing the linear regression model include: The planar interdigitated electrode microwave sensor was inserted into different containers to obtain reference electromagnetic information of reference traditional Chinese medicine decoctions of different concentrations. The vector network analyzer converts the reference electromagnetic information into reference S-parameters; Extract the reference S-parameters corresponding to the calibration frequency points as calibration S-parameters; The linear regression model is fitted based on the absolute value of the calibrated S-parameters and the heavy metal concentration of the benchmark traditional Chinese medicine decoction.

7. The method for detecting heavy metal concentration according to claim 6, characterized in that, The steps for selecting the calibration frequency point include: Traverse all reference frequencies within the preset frequency band; The absolute value of the benchmark S-parameter increases monotonically with the heavy metal concentration of the benchmark traditional Chinese medicine decoction as the benchmark frequency point; The absolute values ​​of the reference S-parameters of the pre-selected frequency points and their corresponding heavy metal concentrations in the reference traditional Chinese medicine decoctions are linearly fitted. The pre-selected frequency point with the highest goodness of fit is selected as the calibration frequency point.

8. The method for detecting heavy metal concentration according to claim 6, characterized in that, The step of fitting the linear regression model based on the absolute value of the calibrated S-parameters and the heavy metal concentration of the benchmark traditional Chinese medicine decoction includes: fitting the linear regression model using the least squares method based on the absolute value of the calibrated S-parameters and the heavy metal concentration of the benchmark traditional Chinese medicine decoction.

9. The method for detecting heavy metal concentration according to claim 8, characterized in that, The formula for the linear regression model is: Where y is the absolute value of the calibration S-parameter corresponding to the calibration frequency point, x is the representative value of the heavy metal concentration, k is the slope, and b is the intercept.

10. The method for detecting heavy metal concentration according to claim 7, characterized in that, The preset frequency band is 0GHz-8GHz, and the calibration frequency point is 0.44GHz.

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