A temperature and gas dual-parameter sensor measurement method and sensor suitable for high-temperature and temperature change environment

Abstract

The present application relates to the technical field of sensor monitoring, and provides a temperature and gas dual-parameter sensor measurement method and sensor suitable for high-temperature and temperature change environment, to solve the problems that existing metal oxide sensors are difficult to work at high temperature and are difficult to decouple, etc., the method comprises the following steps: obtaining a microwave electromagnetic signal emitted by an interrogation antenna, calculating a reflection coefficient based on the microwave electromagnetic signal, and extracting a resonance frequency and an amplitude depth in the reflection coefficient based on a preset dual-parameter decoupling design; based on the resonance frequency, calculating a to-be-measured environment temperature value according to a preset frequency-temperature relationship model; and simultaneously based on the amplitude depth, calculating a to-be-measured environment gas concentration value according to a preset amplitude-gas concentration relationship model. The present application can realize in-situ monitoring of dual parameters in a wide temperature change range of 25 DEG C to 400 DEG C, without the need of built-in heating elements, and has the outstanding advantages of fast response, high reliability and strong environmental adaptability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensor monitoring, in particular to a temperature and gas dual-parameter sensor measurement method and sensor suitable for high-temperature and temperature change environment. BACKGROUND

[0002] Metal-oxide-semiconductor (MOS) gas sensors have a history of more than 60 years. With the advantages of high sensitivity, fast response and low cost, such sensors have shown broad prospects for industrialization in air quality detection applications in residential, industrial and automotive environments. The traditional use of such sensors is to measure the change in conductivity of the sensitive material on the MOS gas sensor. However, MOS gas sensors are limited by operating temperature, and they usually require a miniature heating device to control and generate a specific temperature cycle while obtaining the resistance value at the corresponding temperature. The above-mentioned active heating strategy has caused a series of problems, such as decreased stability, long-term drift, high power consumption, accelerated aging, and unstable sensitivity or signal-to-noise ratio. Researchers have invested a lot of effort to solve the above problems through micro-hotplate, cyclic temperature modulation, advanced chemical metrology models and convolutional neural networks, and have made many encouraging progress. However, people are still looking for a method to avoid introducing noise from the source. It is well known that temperature changes will directly change the conductivity of the sensitive material on the MOS gas sensor; in addition, the temperature cycle strategy requires preset parameter configuration (including specific temperature points and their corresponding duration), and the algorithm compares the resistivity measurement values at different temperature cycles with empirical data to analyze and calculate the gas concentration. However, higher environmental temperature conditions or unpredictable sudden random temperature changes will interfere with the above calculation results, and even cause the temperature modulation strategy to fail to operate normally. Therefore, accurate measurement of gas concentration in a wide range, fast or random temperature change environment is a common and urgent problem in the industry.

[0003] Previous studies on the role of temperature have shown that MOS gas sensors need to operate at higher temperatures to achieve the following purposes: activate surface defects and generate effective gas-sensitive signals; overcome energy barriers to trigger gas-sensitive reactions; or promote oxygen molecules to capture electrons from metal oxides and dissociate into charged oxygen ions, which then interact with specific target gases. In summary, the change in MOS gas sensor conductivity with gas concentration relies on the participation of thermal energy.

[0004] In summary, the core dilemma of the prior art lies in its deep dependence on "active heating" and "bulk conductivity measurement", which makes it inherently difficult to adapt to high-temperature and wide-range, rapid or random temperature change environments accompanied by high temperature, and unable to realize in-situ, synchronous and accurate measurement of temperature and gas concentration. Developing a new method that fundamentally avoids these defects from the sensing mechanism has become a key problem that needs to be solved in the field. SUMMARY

[0005] To solve at least one of the above technical problems in the prior art, the present application provides a temperature and gas dual-parameter sensor measurement method and sensor suitable for high-temperature and temperature change environments.

[0006] In a first aspect, the present application provides a temperature and gas dual-parameter sensor measurement method suitable for high-temperature and temperature change environments, the method comprising:

[0007] acquiring a microwave electromagnetic signal emitted by an interrogation antenna, and calculating a reflection coefficient based on the microwave electromagnetic signal, and extracting a resonance frequency and an amplitude depth in the reflection coefficient based on a preset dual-parameter decoupling design;

[0008] based on the resonance frequency, calculating a measured environmental temperature value according to a preset frequency-temperature relationship model; and based on the amplitude depth, calculating a measured environmental gas concentration value according to a preset amplitude-gas concentration relationship model.

[0009] In an optional embodiment, the construction of the preset frequency-temperature relationship model comprises:

[0010] The complementary open resonant structure of the temperature and gas dual-parameter sensor produces electromagnetic resonance under the microwave excitation of the microwave electromagnetic signal, and the resonance frequency of the electromagnetic resonance is determined by the equivalent inductance and equivalent capacitance of the complementary open resonant structure;

[0011] wherein the equivalent capacitance is dominated by the capacitance component provided by the dielectric substrate of the temperature and gas dual-parameter sensor, and the dielectric substrate is made of a material whose dielectric constant changes monotonically with temperature;

[0012] When the environmental temperature rises, the dielectric constant of the dielectric substrate increases with the environmental temperature, and the equivalent capacitance increases with the dielectric constant of the dielectric substrate, which causes the resonance frequency to shift towards low frequency;

[0013] According to the mapping relationship between the shift amount of the resonance frequency and the environmental temperature, a preset frequency-temperature relationship model is constructed.

[0014] In an optional embodiment, the construction of the preset amplitude-gas concentration relationship model comprises:

[0015] The gas sensitive layer of the warm gas dual parameter sensor adsorbs sensitive gas in the environment, thereby generating a carrier concentration variation amplitude; the higher the sensitive gas concentration is, the greater the carrier concentration variation amplitude is;

[0016] The carrier concentration variation causes the gas sensitive layer to change in a microwave frequency band corresponding to the microwave electromagnetic signal, so that the conductivity of the gas sensitive layer changes, thereby affecting the dielectric loss characteristics of the gas sensitive layer, causing the absorption capacity of the gas sensitive layer to change, finally modulating the energy of the reflected signal and changing the amplitude depth.

[0017] According to the response relationship between the sensitive gas concentration and the amplitude depth, a preset amplitude gas concentration relationship model is constructed.

[0018] In a second aspect, the present application provides a warm gas dual parameter sensor suitable for high temperature and temperature change environment, which can perform the measurement method of the warm gas dual parameter sensor suitable for high temperature and temperature change environment as described in the first aspect and any optional embodiment. The warm gas dual parameter sensor adopts a multi-layer planar structure, which includes, from bottom to top:

[0019] A bottom metal ground layer completely covers the lower surface of the dielectric substrate.

[0020] A dielectric substrate is arranged on the bottom metal ground layer.

[0021] A top metal layer is patterned on the upper surface of the dielectric substrate by a micro-nano processing technology, and the top metal layer integrates: a square complementary open resonant ring located in the center as a main resonant unit; a plurality of periodically arranged ring-shaped complementary open resonant rings symmetrically distributed on both sides of the square complementary open resonant ring, and the opening directions of the ring-shaped complementary open resonant rings on both sides are opposite, and the square complementary open resonant ring and the ring-shaped complementary open resonant ring together form an artificial electromagnetic super material waveguide structure for guiding and localizing electromagnetic field.

[0022] A gas sensitive layer is coated on the square complementary open resonant ring by spraying and heat treatment process, and is kept apart from the ring-shaped complementary open resonant ring.

[0023] In an optional embodiment, the dielectric substrate is made of aluminum oxide ceramic material with high thermal conductivity, high insulation and positive temperature coefficient of dielectric constant, and the upper and lower surfaces thereof form firm ohmic contact and mechanical connection with the bottom metal ground layer and the top metal layer respectively through magnetron sputtering or sintering process.

[0024] In an alternative embodiment, the gas sensitive layer is a porous titanium dioxide film, the planar size of the gas sensitive layer is 15mm*15mm, and the key thickness parameter of the gas sensitive layer is 240nm.

[0025] In an alternative embodiment, the preparation of the gas sensitive layer comprises the following steps:

[0026] Slurry preparation: mix the nanometer titanium dioxide powder with deionized water at a weight ratio of 1:2, and add a dispersing agent to obtain a mixed slurry;

[0027] Homogenization treatment: sequentially perform 10 minutes of magnetic stirring, 60 minutes of ultrasonic vibration, and 10 minutes of secondary magnetic stirring on the mixed slurry to obtain a suspension;

[0028] Masking and spraying: use a traceless masking tape to cover the non-coating area of the temperature-gas dual-parameter sensor, and use a high-pressure air spraying method to spray the suspension onto the target area in three layers;

[0029] Drying treatment: after spraying, dry the temperature-gas dual-parameter sensor to remove the solvent and stabilize the film structure.

[0030] In an alternative embodiment, it further comprises:

[0031] According to the preset dual-parameter decoupling design, the sensor is designed, including selecting aluminum oxide ceramic as the medium substrate material; through structural design, it is ensured that the medium substrate between the bottom metal grounding layer and the top metal layer does not contact the measured environmental gas, thereby sealingly protecting the medium substrate; at the same time, the gas sensitive layer is only applied to the center of the temperature-gas dual-parameter sensor and is located above the square complementary opening resonant ring.

[0032] Compared with the prior art, the beneficial effects of the present application are:

[0033] By proposing an innovative sensing mechanism of microwave transduction of metal oxide surface carrier concentration fluctuation, and combining with a unique complementary opening resonant structure, the industry problem of difficult simultaneous and in-situ measurement of temperature and gas concentration in a wide range, fast or random temperature change environment accompanied by high temperature is fundamentally solved; the temperature-gas dual-parameter sensor constructed in the present application can simultaneously and zero-delay decouple the environmental temperature and gas concentration information using a single measurement of microwave reflection coefficient in a high temperature and temperature change environment without built-in heating elements or complex circuits, realizing dual-parameter measurement with decoupling characteristics, and having high reliability, strong environmental adaptability and excellent engineering application potential. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the accompanying drawings needed to be used in the description of the specific embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0035] Figure 1 is a structural schematic diagram of a temperature and gas dual-parameter sensor according to an embodiment of the present application;

[0036] Figure 2 is a schematic diagram of the installation position of a titanium dioxide porous film according to an embodiment of the present application;

[0037] Figure 3 is a flowchart of a measurement method of a temperature and gas dual-parameter sensor suitable for high-temperature and temperature-varying environments according to an embodiment of the present application;

[0038] Figure 4 is a schematic diagram of an artificial magnetic metamaterial structure based on a metal split ring resonator (SRR) according to an embodiment of the present application;

[0039] Figure 5 is a schematic diagram of a typical geometric configuration of a square complementary split ring resonator according to an embodiment of the present application;

[0040] Figure 6 is a schematic diagram of a typical geometric configuration of a ring complementary split ring resonator according to an embodiment of the present application;

[0041] Figure 7 is a schematic diagram of an inductance-capacitance equivalent circuit of a lumped element according to an embodiment of the present application;

[0042] Figure 8 is a schematic diagram of a temperature response result according to an embodiment of the present application;

[0043] Figure 9 is a schematic diagram of the response result of a temperature and gas dual-parameter sensor to ammonia concentration according to an embodiment of the present application;

[0044] Figure 10 is a schematic diagram of the influence result of ammonia concentration on the resonant frequency in the temperature range of 25-400℃ according to an embodiment of the present application. DETAILED DESCRIPTION

[0045] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0046] In the fields of chemical production, steel smelting, energy exploration, aerospace, etc., real-time capture of real parameters such as temperature, gas concentration, pressure, stress, flow rate, etc. under in-situ working conditions can provide the most accurate and basic data support for improved design decisions, control of product quality, and optimization of equipment performance. However, the special environment of high temperature, wide range of random temperature variation, etc. under the above working conditions poses a severe challenge to conventional testing methods. For example, in production scenarios such as flue gas denitrification, high-temperature pyrolysis hydrogen production, non-soluble metal smelting, sulfur deposition purification, etc. and energy conversion systems such as gas turbines, nuclear reactors, aircraft engines, etc., not only do they need to face high temperatures above 150℃, but also are accompanied by various intermediate reaction gases such as ammonia, hydrogen sulfide, carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide, water vapor, hydrogen chloride, sulfur dioxide, sulfur trioxide, etc. The gas concentration of various intermediate reactions not only directly affects the system working condition, but also can accelerate the corrosion failure of equipment materials, affecting the safety, efficiency and service life of the system. The simultaneous measurement of temperature-gas concentration under the above harsh environment is not only urgent, but also faces great difficulties and challenges.

[0047] Take the flue gas denitrification in the process of municipal solid waste incineration as an example. Flue gas denitrification process is a key technology to reduce nitrogen oxide emissions. Through the catalyst, nitrogen oxides are reduced to harmless nitrogen and water in a specific temperature range, and is widely used in coal-fired power plants, industrial boilers and steel production fields. The effectiveness of flue gas denitrification process is closely related to the reaction temperature. Different denitrification technologies use different catalysts and have specific requirements for temperature, which are generally divided into three temperature zone processes, including low temperature process (70-250℃), medium temperature process (250-500℃), and high temperature process (above 500-1100℃). Take the most widely used selective catalytic reduction (SCR) process as an example, its reaction temperature range is large, usually between 70℃ and 500℃.

[0048] These processes involve specific temperature ranges and multiple gas components, and there are strict requirements for accurate detection of temperature and gas concentration. For example, when the inlet flue gas temperature of the selective catalytic reduction device is lower than the optimal range for denitration, the nitrogen oxide emissions will increase. The flue gas temperature may change due to factors such as load changes of industrial boilers, fluctuations in fuel composition, etc., and needs to be monitored in real time to adjust operating parameters. Nitrogen oxide emission prediction is crucial for improving the efficiency of the denitration system in the municipal solid waste incineration process. The initial concentration of nitrogen oxides in the flue gas needs to be accurately measured before entering the denitration reactor, which provides baseline data for evaluating the performance of the denitration system and calculating the denitration efficiency. At the same time, the amount of ammonia gas as a reducing agent also needs to be accurately controlled. Excessive ammonia gas can cause "ammonia slip", causing secondary pollution, while insufficient ammonia gas can reduce the removal efficiency of nitrogen oxides. However, because of the complex changes in the composition of the incinerator feed and the operating mode, and the presence of high temperatures and wide temperature changes during operation, there is a lack of accurate in-situ gas concentration measurement methods.

[0049] In related technologies, for the problem of in-situ measurement of gas concentration in high-temperature environment, existing metal oxide semiconductor gas sensors are difficult to adapt to environmental temperatures above 125℃ due to the internal integration of conventional circuits. Other gas measurement schemes such as ultraviolet differential absorption spectroscopy, tunable diode laser absorption spectroscopy, and Fourier transform infrared spectroscopy are commonly used for gas concentration measurement in high-temperature environments, but they are all non-in-situ measurement methods. The core components of a surface acoustic wave gas sensor include only a piezoelectric substrate and an interdigital transducer, which can be made entirely of high-temperature-resistant piezoelectric materials. There are no internal circuits, and only surface acoustic wave signals are excited and received by external circuits, avoiding the aging and short circuit risks of electronic components at high temperatures. Not only is it suitable for high-temperature environments, but it also performs excellently in multi-parameter measurement. In terms of simultaneous measurement of temperature and gas concentration, surface acoustic wave sensors have made some encouraging progress, but they face difficulties and challenges in decoupling because both temperature and gas concentration are expressed through acoustic wave frequency. In-situ gas sensors made of high-temperature-resistant materials such as zirconia and zeolites cannot achieve simultaneous measurement of temperature and gas concentration.

[0050] In existing technologies, for the problem of in-situ measurement of gas concentration in temperature-varying environments, existing metal oxide semiconductor gas sensors require active heating (temperature cycling) strategies and pre-configured parameters (including specific temperature points and their corresponding durations). By comparing the resistivity measurement values at different temperature cycles with empirical data, the gas concentration can be analyzed and calculated. However, higher environmental temperature conditions or unpredictable sudden random temperature changes can interfere with the above calculation results, and even cause the temperature modulation strategy to fail to operate normally.

[0051] In the prior art, the surface acoustic wave gas sensor works by detecting the frequency or phase shift change of the acoustic wave caused by the interaction between the gas molecules and the surface of the surface acoustic wave gas sensor. Temperature change will cause the thermal expansion and acoustic velocity change of the piezoelectric substrate (such as quartz, aluminum nitride or lithium niobate) in the surface acoustic wave gas sensor, resulting in a shift in the resonant frequency, and temperature compensation measures need to be taken. However, in the case of rapid temperature change or wide range of temperature change, the difference between the thermal expansion coefficient of the substrate material (such as quartz, lithium niobate) of the medium substrate and the gas sensitive layer, the nonlinear frequency-temperature relationship presented in the wide temperature range, the path asymmetry error, the response delay under rapid temperature change and other factors need to be considered, which greatly increases the design difficulty.

[0052] In the prior art, for the problem of using metal oxide semiconductor materials for gas sensing at room temperature, the MOS gas sensor needs to respond to the gas at a higher temperature. By using a built-in micro-heating plate, an active heating strategy is adopted to activate surface defects and generate effective gas sensitive signals, or to overcome the energy barrier to trigger the gas sensitive reaction, or to promote oxygen molecules to capture electrons from the metal oxide and dissociate into charged oxygen ions, which then interact with specific target gases. In summary, the bulk conductivity of the MOS gas sensor changes with the change in gas concentration, and this sensitive characteristic relies on the participation of thermal energy.

[0053] In the prior art, for the problem of time synchronization of temperature and gas concentration measurement, metal oxide semiconductor gas sensors were originally used only to measure gas concentration, but due to the problem of temperature interference with gas concentration, they gradually developed into a technology system that measures both temperature and gas simultaneously to achieve feedback compensation. Although integrating a temperature measurement module inside the chip of the metal oxide semiconductor gas sensor can achieve temperature compensation, temperature measurement and gas concentration measurement are not completely synchronized. Similarly, surface acoustic wave sensors also need to use temperature compensation for gas concentration, but both cannot achieve zero delay in theory. In a fast temperature change environment, the problem of temperature response delay needs to be paid extra attention to.

[0054] In view of the various defects of the existing sensors in actual application, the present application provides a temperature and gas dual parameter sensor measurement method embodiment suitable for high temperature and temperature change environment. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0055] Figure 1 is a structural schematic diagram of a temperature and gas dual parameter sensor according to an embodiment of the present application. The temperature and gas dual parameter sensor adopts a multi-layer planar structure, which includes, from bottom to top, in order:

[0056] a bottom metal ground layer completely covering the lower surface of the dielectric substrate;

[0057] a dielectric substrate stacked on the bottom metal ground layer;

[0058] a top metal layer patterned on the upper surface of the dielectric substrate by a micro-nano processing technology, the top metal layer integrated with: a square complementary split-ring resonator (S-CSRR) at the center as a main resonant unit; and a plurality of periodically arranged ring complementary split-ring resonators symmetrically distributed on both sides of the square complementary split-ring resonator, and the opening directions of the ring complementary split-ring resonators on both sides are opposite, which together form an artificial electromagnetic metamaterial waveguide structure for guiding and localizing electromagnetic field;

[0059] a gas sensitive layer coated on the square complementary split-ring resonator by a spraying and heat treatment process, and spaced apart from the ring complementary split-ring resonators.

[0060] In this embodiment, the temperature and gas dual-parameter sensor includes, from top to bottom, a gas sensitive layer, a top metal layer, a dielectric substrate, and a bottom metal ground layer; the top metal layer is integrated with a single square complementary split-ring resonator (S-CSRR) and a plurality of periodically arranged ring complementary split-ring resonators, and C-shaped ring complementary split-ring resonators (C-CSRRs) are used in this application; the square complementary split-ring resonator is located at the center of the top metal layer; the ring complementary split-ring resonators are located on both sides of the top metal layer, and the opening directions of the ring complementary split-ring resonators on both sides are opposite. The dielectric substrate, the top metal layer, the bottom metal ground layer, and the ring complementary split-ring resonators form a planar waveguide, and the square complementary split-ring resonator acts as a resonant circuit and transmits wireless signals. The gas sensitive layer is coated on the square complementary split-ring resonator in the central position of the temperature and gas dual-parameter sensor. In practical applications, titanium dioxide can be used as the core material of the gas sensitive layer, and metal oxide sensitive materials such as tin dioxide, zinc oxide, tungsten trioxide, iron oxide, and molybdenum disulfide, as well as doped modified materials formed by doping platinum, palladium, gold, etc. in the above-mentioned materials or heterostructures formed by multiple metal oxides, or structure modified materials formed by nano-structuring (into nanoparticles, nanofibers, hollow spheres, etc.), defect engineering (by introducing oxygen vacancies such as oxygen-deficient titanium dioxide through calcination, reduction, etc.) can be used to make the gas sensitive layer have gas sensing capability, and the present application is not limited thereto.

[0061] In this embodiment, the specific size parameters of the constructed temperature and gas dual-parameter sensor are shown in Table 1.

[0062] Table 1

[0063]

[0064] Optionally, the medium substrate is made of alumina ceramic material with a positive temperature coefficient of dielectric constant, and the upper and lower surfaces of the medium substrate are respectively formed into firm ohmic contact and mechanical connection with the bottom metal grounding layer and the top metal layer through magnetron sputtering or sintering process.

[0065] Optionally, the gas sensitive layer is a porous titanium dioxide film, the medium substrate has a planar size of 15mmx15mm, and a key thickness parameter of the medium substrate is 240nm.

[0066] Optionally, the preparation of the gas sensitive layer includes the following steps: slurry preparation: mixing high specific surface area nano-titanium dioxide powder and deionized water at a weight ratio of 1:2, and adding a dispersing agent to obtain a mixed slurry; homogenization treatment: sequentially performing 10-minute magnetic stirring, 60-minute ultrasonic vibration and 10-minute secondary magnetic stirring on the mixed slurry to obtain a suspension; mask and spraying: covering the non-coating area of the temperature-gas dual-parameter sensor with a traceless mask tape, and using a high-pressure air spraying method to spray the suspension to the target area in three times layer by layer; drying treatment: after spraying, drying the temperature-gas dual-parameter sensor.

[0067] In this embodiment, Figure 2The uppermost gray square block in the middle represents a titanium dioxide porous film. To prepare a high-quality titanium dioxide porous film, first, mix nano-titanium dioxide powder with a high specific surface area (i.e., the total surface area of the nano-titanium dioxide powder per unit mass is much higher than that of conventional materials) with deionized water at a weight ratio of 1:2, and add an appropriate amount of dispersant to prevent agglomeration. The mixed slurry is subjected to magnetic stirring for 10 minutes (primary dispersion), ultrasonic vibration for 60 minutes (deep depolymerization and improved uniformity), and then subjected to secondary magnetic stirring for 10 minutes to ensure that the mixed slurry has good rheological properties and stability, forming a homogeneous suspension suitable for spraying. Thin film deposition is performed using a high-pressure air spraying method. By adjusting the fan angle of the spray nozzle, compressed air pressure, slurry flow rate, and spraying distance, controllable atomization and uniform deposition of the titanium dioxide suspension are achieved. To accurately define the coating area, a non-marking masking tape is used for area protection to avoid contamination of other circuit parts by sensitive materials. The entire spraying process is divided into three layers, and each layer is sprayed and then subjected to short air drying. Finally, a titanium dioxide porous film with a thickness of about 240 nm is formed. The porous structure is beneficial for the rapid adsorption and desorption of gas molecules, improving the response speed and sensitivity. After spraying, the prepared temperature and gas dual-parameter sensor is placed in an 80°C vacuum oven for drying for 30 minutes to completely remove moisture and stabilize the film structure. The dried titanium dioxide porous film does not need additional annealing to have preliminary sensitive properties, but in actual applications, it will be further heat-treated at 400°C to enhance the connection between grains and optimize its gas sensitivity.

[0068] In this embodiment, since the temperature and gas dual-parameter sensor needs to withstand high temperature, and the dielectric constant of the material between the electrodes should not be sensitive to the gas, the base material of the temperature and gas dual-parameter sensor in the present application is selected as aluminum oxide ceramic. At the same time, in order to ensure the convenience of decoupling, it is necessary to avoid the coupling interference of the sensitive gas concentration on the resonant frequency as much as possible. As known from the sensitive mechanism of the resonant frequency, the resonant frequency of the complementary split-ring resonator (CSRR) is mainly affected by the coupling capacitance between the bottom metal ground layer and the ground plane. Therefore, the structure design of the temperature and gas dual-parameter sensor must ensure that the inter-electrode dielectric between the bottom metal ground layer and the ground plane is well protected so that it does not come into contact with the environment gas. Further, as shown in Figure 2 the titanium dioxide porous film used in the present application needs to be coated in the center of the temperature and gas dual-parameter sensor, maintaining a certain distance from the edge of the temperature and gas dual-parameter sensor, thereby reducing the influence of the electric field edge effect.

[0069] To illustrate the performance of the temperature and gas dual-parameter sensor, a set of integrated gas concentration regulation, temperature accurate control, and signal acquisition unit comprehensive experimental platform is taken as an example for detailed description and introduction.

[0070] The comprehensive experiment platform built by the embodiment of the application adopts a temperature control box (model: CGS-MT, SINO AGGTECH, China) to heat or cool the comprehensive experiment platform, so as to realize stable control of the temperature of the closed test chamber in the range of 25°C to 400°C, and the precision can reach ±0.2°C. The temperature-gas dual-parameter sensor designed in the application is fixed on the heating base of the comprehensive experiment platform, so as to ensure good thermal contact between the temperature-gas dual-parameter sensor and the heat source, thereby accurately reflecting the change of the ambient temperature. Such precise temperature control capability is crucial for studying the influence of temperature on the performance of the sensor, and is particularly helpful for analyzing the coupling relationship between temperature and gas-sensitive response.

[0071] In the comprehensive experiment platform, high-purity standard dry ammonia gas and nitrogen gas are accurately mixed by a dynamic gas mixing instrument according to a preset ratio, introduced into the closed test chamber, and a target concentration of ammonia gas sensitive gas environment is generated. The fan arranged in the closed test chamber continuously operates to promote the convection and uniform distribution of the sensitive gas, so as to ensure that the gas-sensitive layer of the temperature-gas dual-parameter sensor is exposed to a stable and uniform ammonia gas sensitive gas environment. In order to realize multi-cycle cyclic testing, nitrogen gas is introduced to thoroughly purge the closed test chamber after each round of testing, effectively removing the residual ammonia gas, completing the environmental reset, thereby ensuring the full desorption and performance recovery of the temperature-gas dual-parameter sensor, and improving the test repeatability and data reliability.

[0072] The comprehensive experiment platform includes a temperature-gas dual-parameter sensor, an interrogation antenna, a temperature control box, a closed test chamber, a humidity generator, a dynamic gas mixing instrument, a vector network analyzer and a signal acquisition unit. Specifically, when the temperature changes, the resonant frequency of the temperature-gas dual-parameter sensor shifts accordingly; when the ammonia gas concentration changes, the electromagnetic response of the temperature-gas dual-parameter sensor changes accordingly, the vector network analyzer records the amplitude change of the reflection coefficient at a fixed frequency, and reflects the change of the electrical characteristics caused by the adsorption of the sensitive gas. By simultaneously detecting the changes of the reflection coefficient amplitude and the resonant frequency, the temperature effect and the gas response can be effectively distinguished, and the dual-parameter synchronous detection can be realized.

[0073] As shown in Figure 3 The application provides a flowchart of a temperature-gas dual-parameter sensor measurement method suitable for high-temperature and temperature-varying environments, including the following steps:

[0074] S1: Obtain the microwave electromagnetic signal emitted by the interrogation antenna, calculate the reflection coefficient based on the microwave electromagnetic signal, and extract the resonant frequency and amplitude depth in the reflection coefficient based on a preset dual-parameter decoupling design.

[0075] In this embodiment, the reflection coefficient is S11 parameter, and the S11 parameter is the input reflection coefficient of port 1 of a vector network analyzer (VNA). The S11 parameter is specifically the ratio of the reflected signal (in complex form) to the incident signal (in complex form). Port 1 is the physical test port marked on the vector network analyzer, and is also the input and reflection port when measuring the S11 parameter. The panel of the VNA usually clearly marks it as "port 1" or the number "1", which is the interface for connecting the test cable. When measuring the S11 parameter, port 1 is responsible for outputting the incident signal to the temperature and gas dual-parameter sensor, and also responsible for receiving the signal reflected by the temperature and gas dual-parameter sensor, and calculating the S11 parameter by comparing the incident and reflected signals.

[0076] S2: Based on the resonance frequency, a preset frequency-temperature relationship model is used to calculate the measured ambient temperature value; and based on the amplitude depth, a preset amplitude-gas concentration relationship model is used to calculate the measured ambient gas concentration value.

[0077] Optionally, the construction of the preset frequency-temperature relationship model comprises: the complementary split ring resonator structure of the temperature and gas dual-parameter sensor generates electromagnetic resonance under the microwave excitation of the microwave electromagnetic signal, and the resonance frequency of the electromagnetic resonance is determined by the equivalent inductance and the equivalent capacitance of the complementary split ring resonator structure; wherein the equivalent capacitance is dominated by the capacitance component provided by the dielectric substrate of the temperature and gas dual-parameter sensor, and the dielectric substrate is made of a material whose dielectric constant monotonically changes with temperature; when the ambient temperature rises, the dielectric constant of the dielectric substrate increases with the ambient temperature, and the equivalent capacitance increases with the dielectric constant of the dielectric substrate, which causes the resonance frequency to shift to low frequency; a preset frequency-temperature relationship model is constructed according to the mapping relationship between the shift amount of the resonance frequency and the ambient temperature.

[0078] In this embodiment, as shown in Figure 4 , it is a kind of artificial magnetic metamaterial structure based on metal open resonant ring (Split Ring Resonator, SRR), this structure can produce strong magnetic dipole resonance response under the excitation of incident electromagnetic wave, and effective magnetic permeability is less than 0. As shown in Figure 5 , Figure 6 , it is the complementary split ring resonator of SRR: the metal ring region in the original SRR structure is replaced by dielectric gap, and the original opening area is filled with metal, so as to obtain "complementary" topology structure. In order to further expand the working bandwidth, improve the field localization ability and enhance the design flexibility, a variety of derivative structures are successively proposed, including nested type, bending type, interdigital type and multi-layer stacked CSRR. In the figure, represents the side length of the outer ring of SRR, represents the side length of the inner ring of SRR, denotes the width at the opening of the SRR, denotes the side length of the outermost ring of the square complementary open resonant ring, denotes the side length of the inner ring of the square complementary open resonant ring, denotes the width at the opening of the square complementary open resonant ring.

[0079] The temperature and gas dual-parameter sensor designed in the present application adopts a CSRR structure, and the equivalent circuit of the lumped element inductance and capacitance thereof is as shown in Figure 7 .

[0080] In the present embodiment, as shown in Figure 7 , the left side is an interrogation antenna loop, wherein an alternating voltage source serves as an excitation source and provides electromagnetic energy required for operation; is an equivalent resistance of the interrogation antenna, reflecting ohmic loss in the loop; is an equivalent inductance of the interrogation antenna, used for generating an alternating magnetic field and transferring energy to the equivalent inductance at the end of the temperature and gas dual-parameter sensor through magnetic coupling. Figure 7 The sensor in is the core functional unit of the temperature and gas dual-parameter sensor, and the equivalent circuit of the sensor is composed of an equivalent resistance , an equivalent inductance and an equivalent capacitance . Among them, characterizes internal loss in the loop; is determined by the size of the metal strip line and the center conductive metal patch; is the equivalent capacitance of the temperature and gas dual-parameter sensor, mainly composed of the coupling capacitance between the bottom metal ground layer and the top metal layer, and also contains the inter-ring capacitance introduced by the S-CSRR structure , which is a key element for realizing the temperature sensing function. Since the coupling capacitance dominates the total capacitance, the inter-ring capacitance Figure 7 can be ignored. Therefore, the sensor in

[0081] can be equivalent to a parallel inductance-capacitance resonant circuit driven by external excitation, and the resonant frequency expression thereof is:

[0082] In the formula, denotes the resonant frequency of the CSRR; denotes the equivalent inductance, which is determined by the size of the metal strip line and the center conductive metal patch (related to , in Table 1) and can be regarded as constant; denotes the equivalent capacitance, which is related to , , medium substrate material characteristics, metal oxide semiconductor material characteristics, coating thickness, etc., are composed of three parts, respectively: coupling capacitance between the bottom surface metal ground layer and the top surface metal layer , coupling capacitance related to the gas sensitive layer , and the inter-loop capacitance introduced by the S-CSRR structure .

[0083] Equivalent capacitance The expression is:

[0084]

[0085] The coupling capacitance between the bottom surface metal ground layer and the top surface metal layer can be expressed as:

[0086]

[0087] In the formula, represents the vacuum permittivity; represents the dielectric constant of the medium substrate at temperature ; represents the effective area of the bottom surface metal ground layer and the top surface metal layer; represents the distance between the bottom surface metal ground layer and the top surface metal layer.

[0088] The dielectric constant of the medium substrate at temperature The relationship between the change of the dielectric constant of the medium substrate with temperature is as follows:

[0089]

[0090] In the formula, is the change in the dielectric constant of the aluminum oxide ceramic due to temperature change; represents the change in temperature; and are the second and first order temperature coefficients, , .

[0091] It can be deduced that temperature rise → dielectric constant of medium substrate increases → coupling capacitance between bottom surface metal ground layer and top surface metal layer increases → equivalent capacitance increases → resonance frequency decreases. Therefore, the resonance frequency of the CSRR can be used to characterize the change of temperature.

[0092] In this embodiment, the sensor temperature response characteristic experiment is verified according to the comprehensive experimental platform built.

[0093] ​As the temperature increases from 25℃ to 400℃, the resonant frequency of the S11 parameter of the temperature-gas dual-parameter sensor gradually shifts from 2.965GHz to a lower frequency of 2.905GHz, with a total frequency shift of... For 0.060 GHz, the individual temperature response results are as follows: Figure 8 As shown. From Figure 8 As can be seen, the temperature-gas dual-parameter sensor exhibits excellent temperature response characteristics, with an average temperature sensitivity of 160 kHz / ℃. The resonant frequency of the sensor changes in real time with temperature, a characteristic attributed to the real-time modulation of carrier concentration on the gas-sensitive layer surface by temperature. As mentioned in previous related technologies, most gas sensors require temperature compensation; however, the time synchronization of temperature acquisition faces severe challenges in rapidly changing temperature environments. The temperature-gas dual-parameter sensor designed in this application can acquire the S11 parameter in a single measurement and simultaneously measure temperature and gas concentration using the resonant frequency and amplitude depth of the S11 parameter. Since temperature and gas concentration are not obtained from two separate sensors, it has the advantage of zero delay, which is crucial for obtaining accurate in-situ parameters in environments where gas and temperature fluctuate simultaneously during waste incineration.

[0094] Optionally, the construction of the preset amplitude gas concentration relationship model includes: adsorbing sensitive gases in the environment through the gas-sensitive layer of the temperature-gas dual-parameter sensor, thereby generating a change in carrier concentration amplitude; the higher the concentration of the sensitive gas, the greater the change in carrier concentration amplitude; the change in carrier concentration causes the gas-sensitive layer to change in the microwave frequency band corresponding to the microwave electromagnetic signal, causing a change in the conductivity of the gas-sensitive layer, which in turn affects the dielectric loss characteristics of the gas-sensitive layer, resulting in a change in the absorption capacity of the gas-sensitive layer to microwaves, ultimately modulating the energy of the reflected signal and changing the amplitude depth; based on the above response relationship between the sensitive gas concentration and the amplitude concentration, a preset amplitude gas concentration relationship model is constructed.

[0095] In the embodiment, a technical scheme of realizing temperature and gas concentration simultaneous measurement by designing microwave transduction metal oxide surface carrier concentration fluctuations (MOSCCF) is designed. When the sensitive gas in the environment contacts the metal oxide semiconductor material surface, micro surface carrier concentration fluctuations will be generated, and the fluctuations have the following characteristics: 1. The change of the environmental gas concentration can directly cause the MOSCCF phenomenon of the metal oxide semiconductor material surface; 2. The MOSCCF does not depend on the participation of thermal energy, but can simultaneously respond to the environmental gas concentration and the environmental temperature, which makes it can adapt to temperature and gas concentration simultaneous measurement under various temperatures and temperature change environments; 3. The specific frequency microwave signal is emitted to the metal oxide semiconductor material, and when the microwave signal interacts with the surface carrier, the phase, amplitude or frequency of the reflected or transmitted signal will change, and by detecting the change of the microwave signal parameters, the related information of the MOSCCF can be obtained; 4. The MOSCCF can represent the concentration of the specific sensitive gas in the environment and the environmental temperature, and the temperature and concentration parameters are perfectly decoupled (one of the binary decoupling equations contains only a single variable) through the technical means of the application.

[0096] The measurement object of the traditional MOS gas sensor is the bulk conductivity of the sensitive material on the traditional MOS gas sensor, and its expression is:

[0097]

[0098] In the formula, represents the bulk conductivity of the sensitive material on the traditional MOS gas sensor; represents the absolute value of the charge of a single charged particle; is the overall density of the carrier on the sensitive material, is the mobility of the carrier on the sensitive material.

[0099] In the embodiment, in the traditional measurement scheme, the change of the bulk conductivity is the object of attention, and the surface effect is ignored. Unlike the traditional scheme, the object of measurement of the application is the surface effect and carrier concentration fluctuations of the gas sensitive layer on the temperature and gas concentration simultaneous sensor. The interaction of the surface effect and carrier concentration fluctuations with the microwave signal can be described by the following theory under the condition of weak loss:

[0100]

[0101]

[0102]

[0103] In the formula, represents the conductivity of the gas sensitive layer on the warm gas dual-parameter sensor; represents the angular frequency of the alternating electric field; and respectively represent the real part and the imaginary part of the dielectric constant of the medium substrate material; represents the tangent of the dielectric loss; represents the attenuation coefficient caused by the dielectric loss; is a phase constant; represents the wave number.

[0104] In this embodiment, the attenuation coefficient caused by the dielectric loss is positively correlated with the amplitude depth of the reflection coefficient, so it is obtained that the conductivity of the gas sensitive layer on the warm gas dual-parameter sensor increases → the imaginary part of the dielectric constant of the medium substrate material increases → the tangent of the dielectric loss increases → the attenuation coefficient caused by the dielectric loss decreases → the amplitude depth of the reflection coefficient decreases.

[0105] In this embodiment, taking the titanium dioxide porous film as the gas sensitive layer and taking ammonia gas as the sensitive gas, the ammonia gas contacts the gas sensitive layer, injects electrons into the gas sensitive layer, increases the surface carrier concentration of the gas sensitive layer, and further causes the conductivity of the surface of the gas sensitive layer made of the titanium dioxide porous film to increase, and finally causes the amplitude depth of the reflection coefficient to decrease. Therefore, the above theory shows that the sensitive gas concentration can be characterized by the amplitude depth of the reflection coefficient, and this characterization does not have a temperature threshold limit.

[0106] In this embodiment, the sensor gas response characteristic experiment is verified according to the comprehensive experimental platform built.

[0107] The sensor gas response characteristic experiment is carried out in a closed test chamber. The whole measurement process is divided into three main stages: pre-cleaning, baseline establishment, and target gas response test.

[0108] In the first stage, the cavity is pre-cleaned.

[0109] In order to ensure the cleanliness of the test environment, first open the gas inlet and outlet valves, start the built-in fan to promote uniform distribution of the gas, and pass in dry nitrogen (purity is 99.9999%), the total flow is set to 500 SLM (Standard Liter per Minute, standard liters per minute), and the blowing is continued for 1 min, which aims to completely remove the residual gas and humidity in the cavity, and ensure the consistency of the internal environment of the closed test chamber before each test.

[0110] In the second stage, the initial response baseline is established.

[0111] After the completion of the cleaning of the closed test chamber, the gas flow is closed, the temperature control box is set to the target test temperature. After the heating platform surface temperature is stable and maintained at the set value for at least 1 min, it is confirmed that the actual working temperature of the temperature-gas dual parameter sensor has reached the preset condition. Subsequently, in the environment of continuously flowing dry nitrogen, at least five sets of reflection coefficient data are collected by using the vector network analyzer, and the average value is taken as the initial response baseline at this temperature. This step ensures that the temperature-gas dual parameter sensor obtains a repeatable reference signal under stable thermodynamic conditions.

[0112] The third stage is the target gas response test.

[0113] 1) Ammonia concentration response test under dry conditions.

[0114] After the completion of the baseline collection, the nitrogen carrier gas flow is continued, and the standard ammonia / nitrogen mixed gas (ammonia, 985 ppm) is switched to as the standard gas. The dynamic gas proportioner is used to accurately proportion, and dry ammonia with six concentrations of 100 ppm, 200 ppm, 300 ppm, 400 ppm, 500 ppm and 600 ppm is generated in turn. The total flow of the carrier gas and the standard gas is still maintained at 500 SLM. The mixed gas with each concentration is flowed for not less than 1 min to ensure that the gas in the closed test chamber is fully replaced and reaches a steady state concentration distribution. After the mixed gas concentration is stable for 1 min, the vector network analyzer collects at least five sets of reflection coefficients, and the average value is taken as the response value at this concentration. Then switch back to pure nitrogen for purging, repeat the cleaning process, and restore to the initial response baseline state, and then proceed to the next concentration test to avoid cross contamination. The above process is repeated at 25℃, 50℃, 100℃, 150℃, 200℃, 250℃, 300℃, 350℃ and 400℃, a total of 9 temperature points, to complete the wide temperature range dry ammonia response characteristic test. From Figure 9 It can be seen that within the wide temperature change range of 25-400℃ (nine temperature nodes), the response of the temperature-gas dual parameter sensor to ammonia concentration is monotonic, and it can work normally at 400℃.

[0115] In this embodiment, a key technical problem to be solved is the decoupling of temperature and gas concentration. The resonance frequency or amplitude depth of the reflection coefficient may be modulated by both temperature and gas. Through the three preset dual parameter decoupling designs of the present application, the resonance frequency of the reflection coefficient of the temperature-gas dual parameter sensor is successfully realized without being affected by the fluctuation of the gas concentration. For example, Figure 10The ammonia concentration versus resonance frequency is shown in the temperature range of 25-400℃, it can be seen that the ammonia concentration changes from 0 to 600PPM, the resonance frequency remains unchanged at the same temperature, and only changes with temperature. This shows that the measured ambient temperature can be directly calculated by the resonance frequency, that is, the perfect decoupling of temperature and gas concentration is achieved (one of the binary decoupling equations contains only a single parameter. In this application, the temperature and gas concentration sensor measured ambient temperature parameter only causes the frequency shift of the reflection coefficient resonance peak).

[0116] The embodiment of the present application proposes a technical scheme of microwave transduction MOSCCF for realizing temperature and gas concentration measurement. Through the scheme, temperature and gas concentration can be simultaneously measured in situ under high temperature and temperature change environment. Four main characteristics of MOSCCF are proposed, which lay a theoretical foundation for the research and development of similar sensors based on MOSCCF measurement. Three preset double-parameter decoupling designs required when measuring temperature and gas concentration by MOSCCF are proposed. Through the preset double-parameter decoupling design, perfect decoupling of temperature and gas concentration can be achieved. The detailed structure size of the temperature and gas concentration sensor and the thickness of the coated titanium dioxide porous film are verified by simulation and experiment. The preparation and modification process details of the titanium dioxide porous film are proposed.

[0117] Through the above-mentioned theory and technical innovation, and through actual measurement verification, the present application realizes simultaneous in-situ measurement of temperature and ammonia concentration in the temperature range of 25-400℃. It not only can adapt to high temperature and temperature change environment, but also has perfect decoupling characteristics. Temperature and gas concentration are different components obtained by one measurement data, and two parameters are completely zero delay, which is crucial for the accuracy of data acquisition.

[0118] Although the embodiments of the present application are described in conjunction with the drawings, various modifications and variations can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A method for measuring temperature and air using a dual-parameter sensor suitable for high-temperature and temperature-changing environments, characterized in that, The method comprises: acquiring a microwave electromagnetic signal emitted by an interrogation antenna, and calculating a reflection coefficient based on the microwave electromagnetic signal, and extracting a resonant frequency and an amplitude depth in the reflection coefficient based on a preset dual-parameter decoupling design; based on the resonant frequency, calculating a to-be-measured ambient temperature value according to a preset frequency-temperature relationship model; and based on the amplitude depth, calculating a to-be-measured ambient gas concentration value according to a preset amplitude-gas concentration relationship model; the preset frequency-temperature relationship model is constructed by: the complementary open resonant structure of the temperature-gas dual-parameter sensor produces electromagnetic resonance under microwave excitation of the microwave electromagnetic signal, and the resonant frequency of the electromagnetic resonance is determined by the equivalent inductance and the equivalent capacitance of the complementary open resonant structure; wherein the equivalent capacitance is dominated by the capacitance component provided by the dielectric substrate of the temperature-gas dual-parameter sensor, and the dielectric substrate is made of a material whose dielectric constant monotonically changes with temperature; when the ambient temperature rises, the dielectric constant of the dielectric substrate increases with the ambient temperature, and the equivalent capacitance increases with the dielectric constant of the dielectric substrate, which causes the resonant frequency to shift to a low frequency direction; a preset frequency-temperature relationship model is constructed according to the mapping relationship between the shift amount of the resonant frequency and the ambient temperature; the preset amplitude-gas concentration relationship model is constructed by: the gas-sensitive layer of the temperature-gas dual-parameter sensor adsorbs a sensitive gas in the environment, thereby producing a carrier concentration change amplitude; the higher the concentration of the sensitive gas, the greater the carrier concentration change amplitude; the carrier concentration change causes the gas-sensitive layer to change in the microwave frequency band corresponding to the microwave electromagnetic signal, causing the conductivity of the gas-sensitive layer to change, thereby affecting the dielectric loss characteristics of the gas-sensitive layer, causing the absorption ability of the gas-sensitive layer to change, ultimately modulating the energy of the reflected signal and changing the amplitude depth; a preset amplitude-gas concentration relationship model is constructed according to the response relationship between the sensitive gas concentration and the amplitude depth.

2. The temperature and gas dual parameter sensor suitable for high temperature and temperature change environment can perform the temperature and gas dual parameter sensor measurement method of claim 1, characterized in that, The temperature-gas dual-parameter sensor adopts a multilayer planar structure, which comprises, from bottom to top: a bottom metal ground layer completely covering the lower surface of the dielectric substrate; a dielectric substrate stacked on the bottom metal ground layer; a top metal layer patterned on the upper surface of the dielectric substrate by a micro-nano processing technology, the top metal layer integrated with: a square complementary open resonant ring located at the center as a main resonant unit; a plurality of periodically arranged ring-shaped complementary open resonant rings symmetrically distributed on both sides of the square complementary open resonant ring, and the opening directions of the ring-shaped complementary open resonant rings on both sides are opposite, and the square complementary open resonant ring and the ring-shaped complementary open resonant ring together form an artificial electromagnetic metamaterial waveguide structure for guiding and localizing electromagnetic field; a gas-sensitive layer coated above the square complementary open resonant ring by a spraying and heat treatment process, and spaced apart from the ring-shaped complementary open resonant ring.

3. The temperature and gas dual parameter sensor suitable for high temperature and temperature changing environment according to claim 2, characterized in that, The medium substrate is made of alumina ceramic material with a positive temperature coefficient of dielectric constant, and the upper and lower surfaces of the medium substrate form ohmic contact and mechanical connection with the bottom metal grounding layer and the top metal layer respectively through magnetron sputtering or sintering process.

4. The temperature and gas dual parameter sensor suitable for high temperature and temperature changing environment according to claim 2, characterized in that, The gas sensitive layer is a porous titanium dioxide film, the planar size of the gas sensitive layer is 15mm×15mm, and the key thickness parameter of the gas sensitive layer is 240nm.

5. The temperature and gas dual parameter sensor suitable for high temperature and temperature varying environment according to claim 4, wherein, The preparation of the gas sensitive layer includes the following steps: Slurry preparation: mix nano-titanium dioxide powder and deionized water in a weight ratio of 1:2, and add a dispersing agent to obtain a mixed slurry; Homogenization treatment: the mixed slurry is subjected to 10 minutes of magnetic stirring, 60 minutes of ultrasonic vibration and 10 minutes of secondary magnetic stirring in sequence to obtain a suspension; Masking and spraying: use a traceless masking tape to cover the non-coating area of the temperature-gas dual-parameter sensor, and use a high-pressure air spraying method to spray the suspension onto the target area in three layers; Drying treatment: after spraying, the temperature-gas dual-parameter sensor is subjected to drying treatment.

6. The temperature and gas dual parameter sensor suitable for high temperature and temperature varying environment according to claim 2, wherein, Further comprising: According to the preset dual-parameter decoupling design, the sensor is designed, including selecting alumina ceramic as the medium substrate material; Through structural design, it is ensured that the medium substrate between the bottom metal grounding layer and the top metal layer does not contact the measured environmental gas, thereby sealing and protecting the medium substrate; at the same time, the gas sensitive layer is only coated in the center of the temperature-gas dual-parameter sensor and located above the square complementary opening resonant ring.

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