A microwave biogas detection device and method

Abstract

The present invention provides a microwave biogas detection device and method, which relates to the field of gas detection technology. The method includes a first substrate plate, a second substrate plate and a resonant cavity; the first substrate plate and the second substrate plate are two identical substrate plates with a cross resonance structure on the surface; the resonant cavity is composed of the first substrate plate and the second substrate plate, and the first substrate plate and the second substrate plate are arranged relatively, and the distance between the two plates is a set value. The present invention can achieve highly sensitive gas detection by utilizing the resonant cavity structure, and a small range of refractive index changes can cause significant changes in the resonance peak, making it extremely sensitive to small concentration changes of biogas. The gas detection device of the present invention has greater tunability, making it suitable for a variety of gas detection tasks, and can accurately measure gas concentrations in a short time, providing faster detection results.

Description

Technical Field

[0001] The present invention relates to the technical field of gas detection, and in particular to a microwave biogas detection device and method. Background Art

[0002] Gas detection devices play a vital role in many fields, ensuring safety, promoting environmental protection and optimizing industrial production processes. With the evolution of technology, the methods and means of gas detection are becoming more abundant and accurate. The main detection methods currently have their own characteristics, but there are also some technical limitations and challenges.

[0003] First, the detection methods of infrared sensors and ultraviolet sensors rely on the absorption characteristics of gases to specific wavelengths of light. This method has high accuracy and high sensitivity, but is limited by the unique absorption spectrum of each gas, so it can usually only detect specific types of gases. In addition, environmental factors such as temperature and humidity may interfere with the measurement results, thereby affecting the accuracy of detection.

[0004] The detection method of thermal conductivity sensors is based on the difference in thermal conductivity of gases. This method is very effective for detecting certain gases, but it may be affected by gas flow rate and sensor temperature, resulting in errors.

[0005] The detection method of semiconductor sensors uses the effect of gas on the resistivity of semiconductor materials for detection. This method has a fast response speed, but may not be sensitive enough to certain gases and may be interfered by other gases in the environment.

[0006] The detection methods of catalytic combustion sensors and electrochemical sensors are both to detect gas concentrations using chemical reactions. Catalytic combustion sensors are very sensitive to combustible gases, but they also have problems with poor selectivity and environmental interference. Electrochemical sensors have high selectivity and sensitivity, but they are also sensitive to humidity, temperature and pressure, so they require frequent calibration and maintenance.

[0007] In summary, there is an urgent need for a gas detection device and method with high tunability, strong environmental adaptability and high accuracy. Summary of the invention

[0008] To this end, the embodiments of the present invention provide a microwave biogas detection device and method, which are used to solve the problems in the prior art that the existing detection methods can only detect specific types of gases, are easily affected by environmental interference, and have low accuracy.

[0009] In order to solve the above problems, an embodiment of the present invention provides a microwave biogas detection device, which includes a first substrate plate, a second substrate plate and a resonant cavity; the first substrate plate and the second substrate plate are two identical substrate plates with a cross resonance structure on the surface; the resonant cavity is composed of the first substrate plate and the second substrate plate, the first substrate plate and the second substrate plate are arranged opposite to each other, and the distance between the two plates is a set value.

[0010] In one embodiment of the present invention, the detection device uses the resonant cavity as a sensor to detect the change in the refractive index of the gas to be detected.

[0011] In one embodiment of the present invention, the material used for the cross resonance structure is a good conductor, including but not limited to copper, aluminum, and silver.

[0012] In one embodiment of the present invention, the first substrate plate and the second substrate plate are both made of high-dielectric and low-loss dielectric materials, including but not limited to aluminum oxide ceramics and titanium oxide ceramics.

[0013] The embodiment of the present invention further provides a microwave biogas detection method, which adopts the microwave biogas detection device described above and specifically includes:

[0014] The gas to be measured is placed between the first substrate plate and the second substrate plate. Electromagnetic waves are incident at different incident angles. The concentration and composition of the gas to be measured are detected by measuring the shift of the microwave transmission peak caused by the change of the refractive index of the gas to be measured.

[0015] In one embodiment of the present invention, the range of the incident angle is 80-90 degrees.

[0016] In one embodiment of the present invention, the following method is used to detect the concentration and composition of the gas to be tested:

[0017] Under the same detection device parameters, the measurement accuracy can be tuned by changing the incident angle of the electromagnetic wave.

[0018] Under the same electromagnetic wave incident angle, the measurement accuracy can be tuned by adjusting the parameters of the detection device.

[0019] In one embodiment of the present invention, the detection device parameters include the thickness of the first substrate plate and the second substrate plate, and the size of the cross resonant structure.

[0020] It can be seen from the above technical solutions that the present invention has the following beneficial effects:

[0021] (1) Compared with other existing gas detection devices, the gas detection device of the present invention can achieve highly sensitive gas detection by utilizing a resonant cavity structure. A small range of refractive index changes can cause significant changes in the resonance peak, making it extremely sensitive to small concentration changes of biogas.

[0022] (2) The gas detection device of the present invention has greater tunability, making it suitable for a variety of gas detection tasks, and can accurately measure gas concentration in a short time, providing faster detection results.

[0023] (3) The resonant cavity sensor of the present invention has the ability to monitor the changes of biogas in real time and can realize dynamic real-time detection.

[0024] (4) The present invention can achieve highly selective detection of specific gases by adjusting the structure of the resonant cavity and optimizing the incident angle of the electromagnetic wave.

[0025] (5) The resonant cavity sensor of the present invention can generally be non-destructively detected by microwave methods. This makes it suitable for non-destructive testing of biological samples and helps to maintain the integrity and repeatability of the samples. The resonant cavity sensor can detect biogas in different microwave frequency bands by adjusting the structural parameters.

[0026] (6) The resonant cavity sensor of the present invention is generally simple in structure, easy to miniaturize and integrate, and suitable for laboratory and portable devices. Miniaturization and integration help to realize portable biogas detection equipment, which is convenient for field application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the implementation cases of the present invention or the technical solutions in the prior art, the following is a brief description of the drawings required for use in the embodiments. By referring to the drawings, the features and advantages of the present invention will be more clearly understood. The drawings are schematic and should not be understood as limiting the present invention in any way. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0028] Figure 1 A schematic diagram of a microwave biogas detection device provided in an embodiment;

[0029] Figure 2 This is a graph showing how the transmittance of the detection device changes with frequency when the TE wave is incident at 88° under different refractive index gases;

[0030] Figure 3 This is a graph showing how the transmittance of the detection device changes with frequency when the TE wave is incident at 89° under different refractive index gases;

[0031] Figure 4After the parameters of the detection device are changed in the embodiment, when the TE wave is incident at 88°, the trend of the transmission rate of the detection device changing with the frequency under the gas to be detected with different refractive indices is shown in the figure;

[0032] Figure 5 After the parameters of the detection device are changed in the embodiment, when the TE wave is incident at 89°, the trend of the transmittance of the detection device changing with frequency under the conditions of the gases to be tested with different refractive indices is shown in the figure.

[0033] Figure numerals in the specification: 1. first substrate plate; 2. second substrate plate; 3. cross resonance structure. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Embodiment 1

[0036] At present, the more mature gas detection methods mainly include semiconductor sensing methods, electrochemical methods, catalytic combustion methods, etc. However, these sensing methods cannot give accurate detection results under relatively complex gas environment conditions. In addition, external environmental conditions such as temperature and humidity can greatly affect the accuracy of the detection results. Therefore, these methods have the disadvantages of poor working stability and high requirements for environmental conditions.

[0037] In addition, electrochemical / thermocatalytic sensors are usually sensitive components that are in direct contact with the gas. They generate heat or electricity through chemical reactions for detection, and are consumable sensors. Therefore, the service life of electrochemical / thermocatalytic sensors will shorten as the frequency and concentration of the detected gas increase. Because they are based on chemical reactions, electrochemical / thermocatalytic sensors react to the same type of gas and have no unique selectivity, which often causes false alarms. Since chemical reactions are very sensitive to humidity, temperature, pressure, and ambient gases, electrochemical / thermocatalytic sensors often cause zero drift problems due to various reasons, making the calibration cycle extremely short.

[0038] In view of the shortcomings of existing methods, such as Figure 1As shown, an embodiment of the present invention proposes a microwave biogas detection device, which includes a first substrate plate 1, a second substrate plate 2 and a resonant cavity; the first substrate plate 1 and the second substrate plate 2 are two identical substrate plates with a cross resonant structure 3 on the surface; the resonant cavity is composed of the first substrate plate 1 and the second substrate plate 2, the first substrate plate 1 and the second substrate plate 2 are arranged opposite to each other, and the distance between the two plates is a set value.

[0039] It can be seen from the above technical solution that the embodiment of the present invention provides a microwave biogas detection device. The microwave biogas detection device designed by the present invention uses a resonant cavity structure to achieve the characteristic of high-sensitivity gas detection. A small range of refractive index changes in biogas can cause significant changes in the transmission peak, so the device has high sensitivity to small concentration changes in biogas. It is worth noting that the electromagnetic wave incident angle and the structural parameters of the device will affect the changes in parameters such as the position, intensity or width of the transmission peak, so the user can customize the detection range and detection accuracy of the detection device according to personal needs.

[0040] In this embodiment, the detection device of the present invention is composed of two identical substrate plates with a cross resonance structure 3 on the surface. The material used for the cross resonance structure 3 is a good conductor, including but not limited to copper, aluminum, and silver. In this embodiment, the material used for the cross resonance structure 3 is copper, with a length of a, a width of w, and a thickness of t1; the first substrate plate 1 and the second substrate plate 2 are both made of high-dielectric and low-loss dielectric materials, including but not limited to alumina ceramics and titanium oxide ceramics. In this embodiment, the first substrate plate 1 and the second substrate plate 2 are both made of alumina ceramic plates (relative dielectric constant ε=8.9), the thickness of the alumina ceramic plate is t2, and the surface is a square with a width of a; the width between the two plates is t3.

[0041] In this embodiment, the detection device of the present invention uses the resonant cavity as a sensor to detect the refractive index change of the gas to be detected. Compared with other existing gas detection devices, the gas detection device of the present invention can achieve highly sensitive gas detection by utilizing the resonant cavity structure. A small range of refractive index changes can cause significant changes in the resonance peak, making it extremely sensitive to small concentration changes of biological gases. The resonant cavity sensor of the present invention has the ability to monitor the changes of biological gases in real time, and can achieve dynamic real-time detection.

[0042] Case 1: The parameters of the detection device are as follows: t1 = 0.035 [mm], t2 = 1 [mm], t3 = 5 [mm], w = 0.2 [mm], a = 10 [mm].

[0043] When TE wave (full name is Transverse Electric Wave, also known as transverse electric wave. It is an electromagnetic wave whose characteristic is that the electric field component is always parallel to the plane of the ceramic plate) is incident at 88°, the transmittance of the detection device changes with frequency under different refractive indices of the gas to be tested. Figure 2 As shown, when the refractive index of the gas to be detected in the detection device changes by only 0.05, the transmission peak position of the detection device will also shift significantly. Using the quality factor formula, it can be calculated that the quality factor of the detection device is 76 at this time.

[0044] When the TE wave is incident at 89°, the trend of the transmission rate of the detection device with frequency under different refractive indices of the gas to be tested is as follows: Figure 3 When the refractive index of the gas to be measured changes by only 0.05, compared with Figure 2 , the transmission peak position of the detection device shows a more significant shift. Calculated by the quality factor formula, the quality factor of the detection device is 148 at this time. It is worth noting that under the same detection device parameters, increasing the incident angle of the electromagnetic wave under the same refractive index of the gas to be tested will cause the transmission rate of the detection device to change more rapidly with frequency, thereby improving the quality factor of the detection device.

[0045] Case 2: The parameters of the detection device are as follows: t1 = 0.035 [mm], t2 = 1 [mm], t3 = 3 [mm], w = 0.2 [mm], a = 10 [mm].

[0046] After changing the parameters of the detection device, when the TE wave is incident at 88°, the trend of the transmission rate of the detection device changing with frequency under different refractive indices of the gas to be tested is as follows: Figure 4 When the refractive index of the gas to be measured changes by only 0.05, compared with Figure 2 The transmission peak position of the detection device shows an obvious shift, but relative to Figure 3 , the transmittance changes slowly. According to the quality factor formula, the quality factor of the detection device is 102, which is between Figure 1 and Figure 3 Compared to Figure 2 , at the same incident angle, the quality factor can be improved by adjusting the parameters of the detection device.

[0047] exist Figure 4 Under the configuration of the detection device parameters shown, when the TE wave is incident at 89°, the trend of the transmission rate of the detection device changing with the frequency under different refractive indices of the gas to be tested is as follows Figure 5As shown. When the refractive index of the gas to be measured changes by only 0.05, the transmission peak position of the detection device shows the most obvious shift. Calculated by the quality factor formula, the quality factor of the detection device is 209 at this time. It is obvious that when the incident angle is increased, under the condition of the gas to be measured with a fixed refractive index, the detection device changes more rapidly with the frequency. The intervals between the resonance peaks corresponding to the gases to be measured with different refractive indices are more obvious, which significantly improves the resolution of the detection device for gas concentration.

[0048] In summary, the present invention can achieve highly selective detection of specific gases by adjusting the structure of the resonant cavity and optimizing the incident angle of the electromagnetic wave. The gas detection device of the present invention has greater tunability, making it suitable for a variety of gas detection tasks, and can accurately measure gas concentrations in a short time, providing faster detection results.

[0049] In this embodiment, the resonant cavity sensor of the present invention can generally be used for non-destructive detection by microwave methods. This makes it suitable for non-destructive detection of biological samples and helps to maintain the integrity and repeatability of the samples. The resonant cavity sensor can achieve detection of biogas in different microwave frequency bands by adjusting the structural parameters.

[0050] In this embodiment, the resonant cavity sensor of the present invention is generally simple in structure, easy to miniaturize and integrate, and suitable for laboratories and portable devices. Miniaturization and integration help to realize portable biogas detection equipment, which is convenient for field application.

[0051] Embodiment 2

[0052] The present invention provides a microwave biogas detection method, which adopts the microwave biogas detection device of the first embodiment, and specifically comprises:

[0053] The gas to be measured is placed between the first substrate plate 1 and the second substrate plate 2. Electromagnetic waves are incident at different incident angles. The concentration and composition of the gas to be measured are detected by measuring the shift of the microwave transmission peak caused by the change in the refractive index of the gas to be measured. The range of the incident angle is 80-90 degrees.

[0054] In this embodiment, the electromagnetic wave is incident at a large angle, and the incident angle is required to be greater than 85°.

[0055] In this embodiment, the following method is used to detect the concentration and composition of the gas to be tested:

[0056] Under the same detection device parameters, the measurement accuracy is tuned by changing the incident angle of the electromagnetic wave; under the same incident angle of the electromagnetic wave, the measurement accuracy is tuned by adjusting the detection device parameters. The detection device parameters include the thickness of the first substrate plate 1 and the second substrate plate 2, and the size of the cross resonant structure 3.

[0057] In this embodiment, the detection device detects information such as gas concentration and composition by measuring the shift of the microwave transmission peak caused by the change in the refractive index of the gas to be measured. By changing the incident angle of the electromagnetic wave, the working frequency band can be changed to achieve tuning of the measurement accuracy, and gas detection can still be achieved for the preset working frequency band. By changing the thickness of the substrate plate, the working frequency band can be changed to achieve tuning of the measurement accuracy, and gas detection can still be achieved for the preset working frequency band. By changing the size of the metal resonant structure, the working frequency band can be changed to achieve tuning of the measurement accuracy, and gas detection can still be achieved for the preset working frequency band. At the same time, the detection device of the present invention is suitable for terahertz design.

[0058] A microwave biogas detection method of this embodiment adopts the aforementioned microwave biogas detection device. Therefore, the specific implementation of the microwave biogas detection method can be found in the embodiment of the microwave biogas detection device above, and will not be repeated here to avoid redundancy.

[0059] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A microwave biogas detection device, characterized in that: It includes a first substrate plate, a second substrate plate and a resonant cavity; the first substrate plate and the second substrate plate are two identical substrate plates with a cross resonant structure on the surface; the resonant cavity is composed of the first substrate plate and the second substrate plate, and the first substrate plate and the second substrate plate are arranged opposite to each other.

2. The microwave biogas detection device according to claim 1, characterized in that: The detection device uses the resonant cavity as a sensor and detects the change in the refractive index of the gas to be detected to achieve gas detection.

3. The microwave biogas detection device according to claim 1, characterized in that: The material used for the cross resonance structure is a good conductor, including but not limited to copper, aluminum, and silver.

4. The microwave biogas detection device according to claim 1, characterized in that: The first substrate plate and the second substrate plate are both made of high-dielectric and low-loss dielectric materials, including but not limited to aluminum oxide ceramics and titanium oxide ceramics.

5. A microwave biogas detection method, characterized in that: The microwave biogas detection device according to any one of claims 1 to 4 specifically comprises: The gas to be measured is placed between the first substrate plate and the second substrate plate. Electromagnetic waves are incident at different incident angles. The concentration and composition of the gas to be measured are detected by measuring the shift of the microwave transmission peak caused by the change of the refractive index of the gas to be measured.

6. The microwave biogas detection method according to claim 5, characterized in that: The range of the incident angle is 80-90 degrees.

7. The microwave biogas detection method according to claim 5, characterized in that: When detecting the concentration and composition of the gas to be tested, the following methods are used: Under the same detection device parameters, the measurement accuracy can be tuned by changing the incident angle of the electromagnetic wave. Under the same electromagnetic wave incident angle, the measurement accuracy can be tuned by adjusting the parameters of the detection device.

8. The microwave biogas detection method according to claim 7, characterized in that: The detection device parameters include the thickness of the first substrate plate and the second substrate plate, and the size of the cross resonance structure.

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