A toxic and harmful gas detection sensor and detection method

Abstract

The present invention relates to a toxic and harmful gas detection sensor and a detection method, belonging to the technical field of gas detection. This toxic and harmful gas detection sensor includes: a housing with an open top; a dielectric substrate horizontally arranged and disposed inside the housing, with the lower surface of the dielectric substrate fixedly connected to the inner wall of the bottom end of the housing; a sensitive dielectric film fixedly connected to the upper surface of the dielectric substrate; an artificial plasmonic resonator fixedly connected to the sensitive dielectric film; a metal microstrip transmission line, one end of which is fixedly connected and electrically connected to the artificial plasmonic resonator, and the other end passes through the housing, and the metal microstrip transmission line is fixedly connected to the sensitive dielectric film. This gas detection sensor has a small volume, low power consumption, strong anti-external interference ability, is easy to integrate, and has high detection sensitivity at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas detection, and particularly relates to a toxic and harmful gas detection sensor and a detection method. Background Art

[0002] With the increasing improvement of living standards, building decoration has increasingly entered people's lives. Decoration can improve people's living quality, but along with it are a large number of toxic and harmful substances contained in decoration materials. As people's attention to this increases, the requirements for environmentally friendly materials in the field of building home decoration are increasing day by day, and the market demand for various highly sensitive toxic and harmful gas sensors has increased rapidly.

[0003] Currently, gas sensors mainly include semiconductor gas sensors, electrochemical gas sensors, and infrared gas sensors. The above several sensors all have problems such as poor detection stability and low detection sensitivity, resulting in inaccurate detection of toxic and harmful gases and affecting the physical condition of the residents. Summary of the Invention

[0004] The present invention provides a toxic and harmful gas detection sensor and a detection method to solve the above technical problems, which can detect toxic and harmful gases with high precision, have good detection stability, and at the same time, the gas detection sensor has a small volume, low power consumption, strong anti-external interference ability, and is easy to integrate.

[0005] The technical solution of the present invention to solve the above technical problems is as follows: A toxic and harmful gas detection sensor, comprising: a housing, the top of the housing is open; a dielectric substrate, the dielectric substrate is horizontally arranged, the dielectric substrate is arranged in the housing, and the lower surface of the dielectric substrate is fixedly connected to the inner wall of the bottom end of the housing; a sensitive dielectric film, the sensitive dielectric film is fixedly connected to the upper surface of the dielectric substrate; an artificial plasmonic resonator, the artificial plasmonic resonator is fixedly connected to the sensitive dielectric film; a metal microstrip transmission line, one end of the metal microstrip transmission line is fixedly connected and electrically connected to the artificial plasmonic resonator, and the other end passes through the housing, and the metal microstrip transmission line is fixedly connected to the sensitive dielectric film.

[0006] The beneficial effects of the present invention are as follows: Toxic and harmful gases are adsorbed by the sensitive medium film, thereby changing the dielectric constant of the entire gas detection sensor. Then, microwaves are sent to the artificial plasmonic resonator. After receiving the microwaves, the artificial plasmonic resonator generates resonance and scatters transmitted waves. The resonance frequency point is obtained from the relationship between the resonance frequency of the artificial plasmonic resonator and the input reflection coefficient. The resonance frequency point will shift following the change of the dielectric constant. When the resonance frequency point drifts, it indicates that toxic and harmful gases are detected. The gas detection sensor of the present invention has high detection sensitivity and high detection accuracy for toxic and harmful gases. At the same time, the structure of the gas detection sensor is small, and it can be well integrated with other microwave circuits, and is more suitable for the current large environment of the Internet of Things.

[0007] Based on the above technical solutions, the present invention can be further improved as follows.

[0008] Further, the artificial plasmonic resonator includes a metal microstrip ring and a plurality of metal strips. The inside of the metal microstrip ring is a resonance cavity. The plurality of metal strips are located in the resonance cavity and are distributed in a circular radial pattern around the center of the metal microstrip ring. One end of each of the plurality of metal strips is fixedly connected to the inner ring wall of the metal microstrip ring, and the other ends of the plurality of metal strips form a circular gap around the center of the metal microstrip ring. The center of the circular gap coincides with the center of the metal microstrip ring. There is a gap between every two metal strips, and all the gaps communicate with the circular gap.

[0009] The beneficial effect of adopting the above further solution is that by distributing a plurality of metal strips in a circular pattern around the center of the metal microstrip ring, the electromagnetic field can be confined in the resonance cavity, which can greatly reduce the interference of external electromagnetic signals on the gas detection sensor and further improve the detection accuracy.

[0010] Further, the diameter of the circular gap is 2 - 10 mm.

[0011] The beneficial effect of adopting the above further solution is to improve the confinement of the electromagnetic field and increase the anti-interference ability.

[0012] Further, the outer diameter of the metal microstrip ring is 10 - 30 mm, and the inner diameter of the metal microstrip ring is 6 - 28 mm.

[0013] The beneficial effect of adopting the above further solution is to be suitable for detection in different-sized environments.

[0014] Further, the metal strip is fan-shaped. The side length of the metal strip is 2 - 9 mm. The arc-shaped side of the metal strip is fixedly connected to the inner ring wall of the metal microstrip ring. The central angle corresponding to the metal strip is 10° - 30°. The number of metal strips is 12 - 36, and the number of gaps is 12 - 36.

[0015] The beneficial effects of adopting the above further scheme are as follows: the confinement effect on the electromagnetic field is better, and it is more capable of improving the detection sensitivity of the gas detection sensor.

[0016] Furthermore, the thickness of the sensitive medium film is 0.02 - 0.1 mm, and the shape of the sensitive medium film is the same as that of the artificial plasmonic resonator and the metal microstrip transmission line.

[0017] The beneficial effects of adopting the above further scheme are as follows: it is beneficial for the sensitive medium film to adsorb toxic and harmful gases.

[0018] Furthermore, the sensitive medium film is a tin oxide film.

[0019] The beneficial effects of adopting the above further scheme are as follows: most toxic and harmful substances can be adsorbed through the tin oxide film.

[0020] Furthermore, it further includes a metal substrate, and the metal substrate is fixedly arranged between the lower surface of the dielectric substrate and the inner wall of the bottom end of the housing.

[0021] The beneficial effects of adopting the above further scheme are as follows: the connection strength between the dielectric substrate and the housing is improved.

[0022] Furthermore, the thickness of the dielectric substrate is 0.2 - 0.8 mm.

[0023] The beneficial effects of adopting the above further scheme are as follows: the strength of the entire gas detection sensor is improved.

[0024] The present invention also provides a detection method using the toxic and harmful gas detection sensor as described above, including the following steps:

[0025] S1. Take a microwave generator, and connect the output end of the microwave generator to the metal microstrip transmission line;

[0026] S2. The microwave generator generates microwaves, and the microwaves are transmitted to the artificial plasmonic resonator through the metal microstrip transmission line. The artificial plasmonic resonator generates resonance and scatters transmitted waves outward;

[0027] S3. Detect the input reflection coefficient of the transmitted waves generated in step S2 and the resonance frequency of the artificial plasmonic resonator to obtain the standard input reflection coefficient and the standard resonance frequency, draw the standard relationship curve between the standard resonance frequency and the standard input reflection coefficient, and obtain the standard resonance frequency point;

[0028] S4. After placing the gas detection sensor in the environment to be detected for a period of time, the post-input reflection coefficient and the post-resonant frequency are detected. According to the post-input reflection coefficient and the post-resonant frequency, a post-relationship curve is plotted to obtain the post-resonant frequency point.

[0029] S5. Compare the standard resonant frequency point obtained in step S3 with the post-resonant frequency point obtained in step S4, and observe whether the post-resonant frequency point shifts. If toxic and harmful gases are detected, the post-resonant frequency point shifts; otherwise, no toxic and harmful gases are detected.

[0030] The beneficial effect of this detection method is that it is more convenient to detect toxic and harmful gases through this detection method. Compared with the existing detection methods, it has high detection efficiency and high detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a top view of the gas detection sensor of the present invention;

[0032] Figure 2 It is a front cross-sectional view of the gas detection sensor of the present invention;

[0033] Figure 3 It is a relationship curve graph of the input reflection coefficient and the resonant frequency of the present invention;

[0034] Figure 4 It is an electric field distribution diagram of the working state of the gas detection sensor of the present invention.

[0035] In the drawings, the list of components represented by each reference numeral is as follows:

[0036] 1. Housing, 2. Dielectric substrate, 3. Metal microstrip transmission line, 4. Metal microstrip ring, 5. Metal strip, 6. Gap, 7. Circular void, 8. Sensitive dielectric film, 9. Metal substrate. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] The principles and features of the present invention will be described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0038] Embodiment

[0039] As Figure 1 - Figure 2 shown, this embodiment provides a toxic and harmful gas detection sensor, including: a housing 1, a dielectric substrate 2, a sensitive dielectric film 8, an artificial plasmonic resonator, and a metal microstrip transmission line 3.

[0040] The top of the housing 1 is open. The housing 1 is rectangular and is used to place the dielectric substrate 2, the sensitive dielectric film 8, the artificial plasmonic resonator, and the metal microstrip transmission line 3, thereby protecting the components inside the housing 1. The dielectric substrate 2 is horizontally arranged and is disposed inside the housing 1. The lower surface of the dielectric substrate 2 is fixedly connected to the inner wall of the bottom end of the housing 1. The sensitive dielectric film 8 is fixedly connected to the upper surface of the dielectric substrate 2. The sensitive dielectric film 8 is used to adsorb toxic and harmful gases in the environment. Different dielectrics on the sensitive dielectric film 8 are for different adsorbed toxic and harmful gases, so as to realize the detection of different toxic and harmful gases. The artificial plasmonic resonator is fixedly connected to the sensitive dielectric film 8. One end of the metal microstrip transmission line 3 is fixedly connected and electrically connected to the artificial plasmonic resonator, and the other end passes through the side wall of the housing 1 for convenient connection with a microwave generator. The metal microstrip transmission line 3 is fixedly connected to the sensitive dielectric film 8. The microwave is transmitted into the artificial plasmonic resonator by connecting the microwave generator to the metal microstrip transmission line 3, and resonance occurs in the artificial plasmonic resonator. Since the dielectric constant on the dielectric substrate 2 is changed after the sensitive dielectric film 8 adsorbs toxic and harmful gases, the resonance frequency of the artificial plasmonic resonator is changed, thereby realizing the detection of toxic and harmful gases. The artificial plasmonic resonator and the metal microstrip transmission line 3 are exposed from the open mouth of the housing 1, facilitating the detection of toxic and harmful gases in the environment.

[0041] The width of the metal microstrip transmission line 3 can be determined according to the dielectric constant of the dielectric substrate 2, and it is required that the input impedance of the metal microstrip transmission line 3 is 50 ohms standard to facilitate good impedance matching with the external circuit. In addition, two metal microstrip transmission lines 3 are provided, which are respectively located on both sides of the artificial plasmonic resonator.

[0042] Specifically, in this embodiment, the artificial plasmonic resonator includes a metal microstrip ring 4 and a plurality of metal strips 5. The metal microstrip ring 4 and the plurality of metal strips 5 are of the same material. The inside of the metal microstrip ring 4 is a resonance cavity. The plurality of metal strips 5 are located in the resonance cavity and are radially distributed in a ring around the center of the metal microstrip ring 4. One end of the plurality of metal strips 5 is fixedly connected to the inner ring wall of the metal microstrip ring 4, and the other ends of the plurality of metal strips 5 form a circular gap 7 around the center of the metal microstrip ring 4. The circular gap 7 is a virtual circle. The ends of the plurality of metal strips 5 close to the center of the metal microstrip ring 4 are not connected to each other. The center of the circular gap 7 coincides with the center of the metal microstrip ring 4. There is a gap 6 between every two metal strips 5, and all the gaps 6 communicate with the circular gap 7. By arranging a plurality of metal strips 5 in the plasmonic resonance cavity, the binding effect on electromagnetic waves can be formed, the change amount of the resonance frequency can be amplified, and in addition, the interference of external electromagnetic signals on the gas detection sensor is greatly reduced, thereby improving the detection sensitivity of toxic and harmful gases.

[0043] Specifically, in this embodiment, the diameter of the circular gap 7 is 2 - 10 mm. The outer diameter of the metal microstrip ring 4 is 10 - 30 mm, the inner diameter of the metal microstrip ring 4 is 6 - 28 mm, and the width of the metal microstrip ring 4 is 1.5 - 3 mm. The thickness of the dielectric substrate 2 is 0.2 - 0.8 mm.

[0044] Specifically, in this embodiment, the metal strip 5 is fan-shaped, the side length of the metal strip 5 is 2 - 9 mm, the arc-shaped side of the metal strip 5 is fixedly connected to the inner ring wall of the metal microstrip ring 4, the central angle corresponding to the metal strip 5 is 10° - 30°, the number of the metal strips 5 is 12 - 36, and the number of the gaps 6 is 12 - 36. At this time, the sensitivity of this gas detection sensor is relatively high, which is more conducive to the detection of toxic and harmful gases.

[0045] Specifically, in this embodiment, the thickness of the sensitive medium film 8 is 0.02 - 0.1 mm, and the shape of the sensitive medium film 8 is the same as that of the artificial plasmonic resonator and the metal microstrip transmission band 3. The part of the sensitive medium film 8 connected to the artificial plasmonic resonator is circular, and the part connected to the metal microstrip transmission band 3 is strip-shaped. Thus, the sensitive medium film 8 has a better effect of adsorbing toxic and harmful gases, thereby improving the detection accuracy of this gas detection sensor.

[0046] Specifically, in this embodiment, the sensitive medium film 8 is a tin oxide film. Of course, the sensitive medium film 8 can also be made of other materials, which can be specifically selected according to the types of toxic and harmful gases to be detected. The tin oxide film or other materials can be plated on the substrate by screen printing or magnetron sputtering for use.

[0047] Preferably, in this embodiment, a metal substrate 9 is further included. The metal substrate 9 is fixedly arranged between the lower surface of the dielectric substrate 2 and the inner wall of the bottom end of the housing 1, and the connection strength between the dielectric substrate 2 and the housing 1 is improved through the metal substrate 9.

[0048] In addition, this embodiment provides a detection method using the above-mentioned toxic and harmful gas detection sensor, including the following steps:

[0049] S1. Take a microwave generator and connect the output end of the microwave generator to the metal microstrip transmission band 3.

[0050] S2. The microwave generator generates microwaves, and the microwaves are transmitted to the artificial plasmonic resonator through the metal microstrip transmission band 3. The artificial plasmonic resonator can receive and emit microwaves. When the artificial plasmonic resonator receives microwaves, the artificial plasmonic resonator generates resonance and scatters transmitted waves outward.

[0051] S3. Detect the input reflection coefficient of the transmission wave generated in step S2 and the resonant frequency of the artificial plasmonic resonator. Since the dielectric constant of the dielectric substrate 2 is a stable value, a standard input reflection coefficient and a standard resonant frequency are obtained. According to the standard input reflection coefficient and the standard resonant frequency, a standard relationship curve between the standard resonant frequency and the standard input reflection coefficient is plotted, and a standard resonant frequency point is obtained based on the plotted standard relationship curve between the standard resonant frequency and the standard input reflection coefficient.

[0052] S4. After placing the gas detection sensor in the environment to be detected for a period of time, as the gas detection sensor is placed in the environment to be detected for a period of time, continue to send microwaves to the artificial plasmonic resonator through the microwave generator, detect the post - input reflection coefficient and the post - resonant frequency, plot a post - relationship curve based on the post - input reflection coefficient and the post - resonant frequency, and obtain the post - resonant frequency point.

[0053] S5. Compare the standard resonant frequency point obtained in step S3 with the post - resonant frequency point obtained in step S4, and observe whether the post - resonant frequency point shifts. If toxic and harmful gases are detected, the post - resonant frequency point shifts; otherwise, no toxic and harmful gases are detected.

[0054] The detection principle is as follows: When the gas detection sensor is placed in the environment to be detected, the sensitive dielectric film 8 will adsorb toxic and harmful gases in the environment. After the sensitive dielectric film 8 adsorbs toxic and harmful gases, it will cause the dielectric constant to change, thereby changing the dielectric constant of the entire gas detection sensor. When the artificial plasmonic resonator receives microwaves, the electromagnetic field of the artificial plasmonic resonator is highly localized. Due to the change in the dielectric constant of the entire gas detection sensor, the resonant frequency of the artificial plasmonic resonator changes linearly with the change in the dielectric constant, so that the measured post - resonant frequency changes. Therefore, the post - relationship curve plotted based on the post - input reflection coefficient and the post - resonant frequency changes, and the post - resonant frequency point obtained thereby shifts relative to the standard resonant frequency point.

[0055] The following is the specific measurement situation using the above - mentioned embodiment.

[0056] Prepare a sample of a toxic and harmful gas detection sensor according to the above - mentioned embodiment, and its geometric parameters of each part are shown in Table 1.

[0057] Table 1

[0058] Component Value Length of the metal microstrip transmission line 20mm Outer diameter of the metal microstrip ring 20mm Inner diameter of the metal microstrip ring 16mm Side length of the metal strip 6mm Central angle corresponding to the metal strip 15o Number of metal strips 24 Width of the metal substrate 40mm Length of the metal substrate 60mm Width of the metal microstrip ring 1.08mm Thickness of the dielectric substrate 0.5mm Thickness of the sensitive dielectric film 0.05mm

[0059] Among them, the dielectric constant εr of the dielectric substrate 2 is 3.52, and the dielectric constant εr of the entire gas detection sensor is 3.0.

[0060] The gas detection sensor is placed in a preset environment to be detected for testing. According to the input reflection coefficient S obtained by the gas detection sensor 11 and the resonance frequency, a relationship curve is plotted. Since the sensitive dielectric film 8 in the gas detection sensor continuously adsorbs toxic and harmful gases, it can be seen that the dielectric constant continuously increases. Specifically, the inventor selected the cases where the dielectric constant εr is 7.0, 11.0, 15.0, and 19.0, as well as the relationship curve when the dielectric constant εr is 3.0, and integrated them together. Specifically, as Figure 3 shown. It can be intuitively seen from Figure 3 that the resonance frequency point continuously shifts with the change of the dielectric constant. Thus, it can be explained that the toxic and harmful gas detection sensor of the present invention can accurately detect whether there are toxic and harmful gases, and the detection accuracy is very high.

[0061] In addition, the inventor also detected the electric field distribution of the gas detection sensor in the working state. Specifically, as Figure 4 shown. It can be seen from Figure 4 that when the gas detection sensor is working, the electric field energy is mainly concentrated inside the resonance cavity of the artificial plasmonic resonator, so that the anti-electromagnetic interference ability of the gas detection sensor is greatly enhanced.

[0062] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A toxic and harmful gas detection sensor, characterized in that, it includes: a housing (1) with an open top; a dielectric substrate (2) which is horizontally arranged and disposed inside the housing (1), and the lower surface of the dielectric substrate (2) is fixedly connected to the inner wall of the bottom end of the housing (1); a sensitive dielectric film (8) fixedly connected to the upper surface of the dielectric substrate (2); an artificial plasmonic resonator fixedly connected to the sensitive dielectric film (8); a metal microstrip transmission line (3), one end of the metal microstrip transmission line (3) is fixedly connected to and electrically connected to the artificial plasmonic resonator, and the other end passes through the housing (1), and the metal microstrip transmission line (3) is fixedly connected to the sensitive dielectric film (8); the artificial plasmonic resonator includes a metal microstrip ring (4) and a plurality of metal strips (5). The inside of the metal microstrip ring (4) is a resonant cavity. The plurality of metal strips (5) are located inside the resonant cavity and are radially distributed in a ring around the center of the metal microstrip ring (4). One end of the plurality of metal strips (5) is fixedly connected to the inner ring wall of the metal microstrip ring (4), and the other ends of the plurality of metal strips (5) form a circular gap (7) around the center of the metal microstrip ring (4). The center of the circular gap (7) coincides with the center of the metal microstrip ring (4). There is a gap (6) between every two metal strips (5), and all the gaps (6) communicate with the circular gap (7).

2. The toxic and harmful gas detection sensor according to claim 1, characterized in that, the diameter of the circular gap (7) is 2 - 10 mm.

3. The toxic and harmful gas detection sensor according to claim 1, characterized in that, the outer diameter of the metal microstrip ring (4) is 10 - 30 mm, and the inner diameter of the metal microstrip ring (4) is 6 - 28 mm.

4. The toxic and harmful gas detection sensor according to claim 1, characterized in that, the metal strip (5) is fan-shaped, the side length of the metal strip (5) is 2 - 9 mm, the arc side of the metal strip (5) is fixedly connected to the inner ring wall of the metal microstrip ring (4), the central angle corresponding to the metal strip (5) is 10° - 30°, the number of the metal strips (5) is 12 - 36, and the number of the gaps (6) is 12 - 36.

5. The toxic and harmful gas detection sensor according to claim 1, characterized in that, the thickness of the sensitive dielectric film (8) is 0.02 - 0.1 mm, and the shape of the sensitive dielectric film (8) is the same as the shapes of the artificial plasmonic resonator and the metal microstrip transmission line (3).

6. The toxic and harmful gas detection sensor according to claim 5, characterized in that, the sensitive dielectric film (8) is a tin oxide film.

7. The toxic and harmful gas detection sensor according to any one of claims 1 - 6, characterized in that, Further included is a metal substrate (9), and the metal substrate (9) is fixedly arranged between the lower surface of the dielectric substrate (2) and the inner wall of the bottom end of the housing (1).

8. The toxic and harmful gas detection sensor according to any one of claims 1-6, characterized in that the thickness of the dielectric substrate (2) is 0.2-0.8 mm.

9. A detection method using the toxic and harmful gas detection sensor according to any one of claims 1-8, characterized in that it includes the following steps: S1. Take a microwave generator, and connect the output end of the microwave generator to the metal microstrip transmission line (3); S2. The microwave generator generates microwaves, and the microwaves are transmitted to the artificial plasmonic resonator through the metal microstrip transmission line (3), and the artificial plasmonic resonator generates resonance and scatters the transmitted wave outward; S3. Detect the input reflection coefficient of the transmitted wave generated in step S2 and the resonance frequency of the artificial plasmonic resonator, obtain the standard input reflection coefficient and the standard resonance frequency, draw the standard relationship curve between the standard resonance frequency and the standard input reflection coefficient, and obtain the standard resonance frequency point; S4. After placing the gas detection sensor in the environment to be detected for a period of time, detect the post-input reflection coefficient and the post-resonance frequency, draw the post-relationship curve according to the post-input reflection coefficient and the post-resonance frequency, and obtain the post-resonance frequency point; S5. Compare the standard resonance frequency point obtained in step S3 with the post-resonance frequency point obtained in step S4, observe whether the post-resonance frequency point shifts. If toxic and harmful gases are detected, the post-resonance frequency point shifts, otherwise no toxic and harmful gases are detected.

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