Half-mode substrate integrated waveguide type microwave gas sensor based on metal-organic framework and preparation method and application of sensing system

Abstract

The invention discloses a half-mode substrate integrated waveguide type microwave gas sensor based on a metal-organic framework. The half-mode substrate integrated waveguide type microwave gas sensor comprises a substrate; the bottom wall is arranged on the lower surface of the substrate in a covering manner; the top wall is arranged on the upper surface of the substrate; the complementary open-loop resonator is etched on the top wall; the sensitive material layer covers the complementary open-loop resonator; wherein the sensitive material is a metal-organic framework material, the top wall and the bottom wall are made of metal copper, and the substrate is a high-frequency dielectric plate; the plurality of via holes are respectively formed in the substrate, the bottom wall and the top wall in a one-to-one correspondence manner; the plurality of via holes serve as side walls of the waveguide on the substrate, and the equivalent magnetic wall is used for replacing the via holes on the other side, so that a closed waveguide structure is formed on the substrate together with the top wall and the bottom wall. The invention further provides a half-mode substrate integrated waveguide type microwave gas sensing system based on the metal-organic framework and application of the half-mode substrate integrated waveguide type microwave gas sensing system.

Description

Technical Field

[0001] The present invention relates to a preparation method and application of a half-mode substrate integrated waveguide type microwave gas sensor and a sensing system based on metal-organic frameworks, belonging to the technical field of microwave gas sensing. Background Art

[0002] In order to monitor the atmospheric environment and human well-being, real-time monitoring of toxic substances in the air has become an important research topic. Among various environmental monitoring technologies, gas sensors have received extensive attention and applications due to their high sensitivity, strong real-time performance, and easy deployment.

[0003] Chemiresistive gas sensors are one of the most widely used sensors in the world at present. They mainly detect gas types and concentrations by relying on the change in the resistance of the material caused by the chemical reaction between the gas and the surface of the sensitive material, and have the advantages of high sensitivity, low cost, small volume, and easy integration.

[0004] The sensitive material usually uses metal oxide semiconductors, such as tin oxide (SnO2), zinc oxide (ZnO), etc. However, the high working temperature and poor selectivity of metal oxide semiconductor materials restrict the long-term development of gas sensors. Metal-organic frameworks (MOFs) have gradually attracted attention in the sensing field due to their diverse and adjustable pore structures and large specific surface areas. However, due to its dependence on the conductivity of the material, MOFs with high resistance are difficult to be directly used for gas sensing, and the material often needs to be modified and optimized.

[0005] Microwave gas sensors measure gas types and concentrations by analyzing the influence of gas on microwave signals (such as frequency shift, amplitude, phase change, etc.), which can effectively avoid the limitations of high-resistance materials in the sensing field. Current research mostly adopts two-dimensional planar circuit structures and three-dimensional waveguide structures. Planar circuits have the advantages of small volume, simple processing, and low cost, but the electric field and magnetic field often intertwine, and the quality factor and electromagnetic field intensity are restricted by the planar circuit structure. The three-dimensional structure of the waveguide cavity can transmit TE mode and TM mode, and can well separate the electric field concentration region and the magnetic field concentration region, making the quality factor of the circuit much higher than that of the planar circuit, and greatly improving the sensitivity of the microwave sensor. However, the cavity resonator of the conventional waveguide structure has a high manufacturing cost and a large volume, which seriously hinders the application of the cavity resonator. Substrate integrated waveguide combines some advantages of traditional waveguide structures and planar circuit structures, and has its unique structural characteristics.

[0006] Although the currently used chemiresistive gas sensors have the advantages of high sensitivity, low cost, easy integration, etc., they are limited by the sensitive materials, have high requirements for the conductivity and working temperature of the materials, and are not applicable to extreme weather; while the substrate integrated waveguide (SIW) microwave gas sensor can overcome the sensing limitations caused by poor material conductivity through tracking the change of dielectric constant during the adsorption process. Secondly, the SIW microwave sensor has a strong and concentrated electromagnetic field distribution and can perform target detection at room temperature, solving the limitation in terms of energy consumption.

[0007] Currently, most microwave gas sensors use planar circuits. Limited by the planar structure, the electric field and magnetic field often intertwine and the quality factor is relatively low; while the waveguide cavity with SIW structure has a closed electromagnetic field structure, and its quality factor is much higher than that of planar circuits, greatly improving the sensitivity of microwave sensors.

[0008] The traditional metal waveguide structure has high manufacturing cost, complex preparation process and large volume; the SIW structure can be integrated with other microwave circuits and components on the same substrate, which is convenient for packaging and miniaturization, with low cost and simple preparation.

[0009] Traditional metal oxide materials used for gas sensing have the disadvantages of poor selectivity and low stability; metal-organic framework materials have stable chemical properties. By adjusting the composition, synthesis conditions and ligands, their pore structures can be controlled. The functional groups and active sites in their organic ligands can bind to different gas molecules through hydrogen bonding, electrostatic and van der Waals interactions, and specifically adsorb specific gases.

[0010] The half-mode SIW is a simplified form designed based on the traditional SIW. It uses an equivalent magnetic wall to replace the metallized vias on one side and utilizes the symmetry of the electromagnetic field to achieve a smaller physical size. By adjusting the size and spacing of the metallized holes or slots, the electromagnetic characteristics of the half-mode SIW can be flexibly controlled to meet different application requirements. At the same time, the half-mode SIW with a compact circuit size can be integrated with other screen circuit components on the same substrate, combining the low-loss characteristics of the waveguide and the easy integration characteristics of the planar circuit. Summary of the Invention

[0011] The present invention designs and develops a half-mode substrate integrated waveguide type microwave gas sensor based on metal-organic framework. Based on the symmetry of the electromagnetic field, only half of the structure of the substrate integrated waveguide is retained, and the vias on the other side are replaced with an equivalent magnetic wall, realizing a compact design.

[0012] The present invention also designs and develops a preparation method of a semi-mode substrate integrated waveguide type microwave gas sensing system based on metal-organic framework, which combines the metal-organic framework material as a sensitive material layer with a microwave gas sensor, and has a simple preparation process and is easy to integrate.

[0013] The present invention also designs and develops an application of a semi-mode substrate integrated waveguide type microwave gas sensing system based on metal-organic framework, which can achieve high-precision detection of specific gases at room temperature, reduce detection energy consumption, and improve the selectivity and sensitivity of gas detection.

[0014] The technical solution provided by the present invention is as follows:

[0015] A substrate integrated waveguide type microwave gas sensor based on metal-organic framework, comprising:

[0016] A substrate;

[0017] A bottom wall, which is covered and arranged on the lower surface of the substrate;

[0018] A top wall, which is arranged on the upper surface of the substrate;

[0019] A complementary split-ring resonator, which is in a U-shaped structure and is etched at the middle position of the top wall;

[0020] A sensitive material layer, which is covered on the complementary split-ring resonator;

[0021] The sensitive material layer is a metal-organic framework material, the materials of the top wall and the bottom wall are copper, and the substrate is a high-frequency dielectric board;

[0022] A plurality of vias, which are respectively and correspondingly opened on the substrate, the bottom wall and the top wall;

[0023] Among them, the plurality of vias act as the side walls of the waveguide on the substrate, and the vias on the other side are replaced by equivalent magnetic walls, so as to form a closed waveguide structure on the substrate together with the top wall and the bottom wall.

[0024] Preferably, the metal-organic framework material is SIFSIX-1-Cu.

[0025] Preferably, the substrate and the bottom wall have the same structure, both are quadrilateral structures, and the size is 24.0 mm × 55.0 mm.

[0026] Preferably, the middle of the top wall is a square structure, and both ends are strip-like structures extending outwards.

[0027] Preferably, the plurality of vias are all circular structures, and are respectively and equally spaced on one side of the top wall, the substrate and the bottom wall.

[0028] Preferably, the sensitive material layer has a square structure with dimensions of 9.0 mm × 9.0 mm.

[0029] A preparation method of a semi-mode substrate integrated waveguide type microwave gas sensing system based on metal-organic framework, characterized by using the semi-mode substrate integrated waveguide type microwave gas sensor based on metal-organic framework, including:

[0030] Step 1: Insulate and waterproof the areas other than the complementary split-ring resonator area on the semi-mode substrate integrated waveguide type microwave gas sensor, and remove impurities from the exposed parts.

[0031] Step 2: Prepare a methanol solution containing SIFSIX-1-Cu, and quickly and evenly brush it on the sensitive area to form a sensitive layer.

[0032] Step 3: After the sensitive layer dries naturally, place the entire semi-mode substrate integrated waveguide type microwave gas sensor in a sealed gas chamber, and connect it to a vector network analyzer, a computer, and a humidifying system to form a complete microwave sensing system.

[0033] Preferably, the metal-organic framework SIFSIX-1-Cu is ground using an agate mortar, and the particle size is 10 - 15 μm.

[0034] Preferably, in the methanol solution containing SIFSIX-1-Cu, the mass of SIFSIX-1-Cu is 50 mg, the mass fraction of the methanol solution is 99.5%, and the thickness of the sensitive layer after natural drying is 0.2 mm.

[0035] An application of a semi-mode substrate integrated waveguide type microwave gas sensing system based on metal-organic framework, using the prepared semi-mode substrate integrated waveguide type microwave gas sensing system based on metal-organic framework to detect various concentrations and various gases.

[0036] The beneficial effects of the present invention:

[0037] (1) The substrate integrated waveguide structure combines the advantages of low cost, simple process, easy integration of the planar circuit structure and low loss, high quality factor of the traditional waveguide structure, and at the same time has its unique structural characteristics.

[0038] (2) The half-mode SIW realizes a compact design and saves space by forming metallized vias or slots on the dielectric substrate to simulate the metal walls of traditional waveguides. By adjusting the size and spacing of the metallized holes or slots, the electromagnetic characteristics of the half-mode SIW can be flexibly controlled to meet different application requirements. The half-mode SIW can be integrated with other planar circuit elements on the same substrate, combining the low-loss characteristics of waveguides and the easy integration characteristics of planar circuits.

[0039] (3) Compared with traditional chemiresistive gas sensors, the substrate integrated waveguide type microwave gas sensor has the advantages of low energy consumption (operating at room temperature), high sensitivity, small material limitations, and can work in harsh environments.

[0040] (4) The high operating temperature and poor selectivity of metal oxide semiconductor materials restrict the long-term development of gas sensors. Metal-organic framework materials (MOFs) have good stability, and the diverse and adjustable pore structures are conducive to improving selectivity, while the high porosity and large specific surface area are beneficial to gas adsorption.

[0041] (5) The half-mode SIW circuit is first combined with metal-organic framework materials for microwave gas sensing. The unique detection mechanism enables the metal-organic framework materials to avoid additional regulation, effectively preventing the loss of material active sites, and at the same time, room temperature detection can effectively reduce energy consumption. Description of the Drawings

[0042] Figure 1 It is a schematic structural diagram of the half-mode substrate integrated waveguide type microwave gas sensor based on metal-organic framework according to the present invention.

[0043] Figure 2 It is a schematic structural diagram of the bottom wall according to the present invention.

[0044] Figure 3 It is a schematic structural diagram of the substrate according to the present invention.

[0045] Figure 4 It is a schematic structural diagram of the top wall according to the present invention.

[0046] Figure 5 It is the electric field and magnetic field distribution of the half-mode substrate integrated waveguide circuit microwave sensor according to the present invention at the resonant frequency.

[0047] Figure 6 It is the equivalent circuit diagram of the sensitive circuit of the half-mode substrate integrated waveguide type microwave gas sensor based on metal-organic framework according to the present invention.

[0048] Figure 7(a) is a schematic structural diagram of the half-mode substrate integrated waveguide type microwave gas sensor based on metal-organic framework according to the present invention.

[0049] Figure 7(b) is the actual circuit layout diagram of the complementary open-loop resonator in the sensitive circuit of the present invention.

[0050] Figure 8 This is the scanning electron microscope photo of the SIFSIX-1-Cu sample used in the microwave gas sensor in the embodiment of the present invention.

[0051] Figure 9 This is the scattering parameter S of the microwave gas sensor in the 0-1000 ppm SO2 atmosphere in the embodiment of the present invention. 21 Curve graph.

[0052] Figure 10 This is the ΔS of the microwave gas sensor in the 0-1000 ppm SO2 atmosphere in the embodiment of the present invention. 21 Response value line graph.

[0053] Figure 11 This is the ΔS of the microwave gas sensor to different gases of 200 ppb in the embodiment of the present invention. 21 Comparison graph of response values. Specific implementation manners

[0054] The following further elaborates on the present invention in conjunction with the attached drawings, so that those skilled in the art can implement it with reference to the text of the specification.

[0055] As Figures 1 - 11 shown, the present invention provides a half-mode substrate integrated waveguide type microwave gas sensor based on a metal-organic framework, including: a bottom wall 110, a substrate 120, a top wall 130, a sensitive material layer 140, a complementary open-loop resonator 150, and a via 160.

[0056] The substrate 120 is horizontally arranged, and a top wall 130 and a bottom wall 110 are respectively arranged on the upper surface and the lower surface of the substrate 120. A complementary open-loop resonator 150 is etched at the middle position on the top wall 130, and the sensitive material layer 140 is covered on the complementary open-loop resonator 150.

[0057] In the present invention, as a preference, the sensitive material layer 140 is a metal-organic framework material, the materials of the top wall 130 and the bottom wall 110 are metallic copper, and the material of the substrate 120 is a high-frequency dielectric board, with the model of Roger RT / duroid 5880, the relative dielectric constant (ε s ) being 2.2, the thickness (h s ) being 0.787 millimeters, and the dielectric loss (tanδs) being 0.0009.

[0058] A plurality of via holes 160 are respectively provided on one side of the substrate 120, the top wall 130 and the bottom wall 110. The plurality of via holes 160 are neatly arranged on one side of the substrate to serve as the side wall of the waveguide, and an equivalent magnetic wall is used to replace the via holes on the other side, thereby forming a closed waveguide structure on the substrate 120 together with the top wall 130 and the bottom wall 110.

[0059] The modified complementary split-ring resonator (MCSRR) is etched in the center of the copper top wall of the half-mode substrate integrated waveguide, so that the electromagnetic wave produces a strong resonance response in the evanescent band of the half-mode SIW, improving the sensitivity of the sensor. The slot structure of the resonator is folded in a "J" shape to reduce the size of the split-ring resonator.

[0060] In the microwave gas sensor, the sensitive circuit includes: a bottom wall 110, a substrate 120, a top wall 130, and a complementary open-ring resonator 150 etched on the top wall 130, and all parts except the sensitive material layer 140 are sensitive circuits. A sensitive layer is coated on the sensitive circuit, and the sensitive circuit and the sensitive layer together form a complete gas sensor.

[0061] On the top wall 130 , the slot of the complementary open-ring resonator 150 is a sensitive area, and a metal-organic framework material is coated as a sensitive material. The sensitive material is coated on the complementary open-ring resonator 150 to form a sensitive material layer 140 .

[0062] The size of the sensitive circuit is 24.0 mm × 55.0 mm, and the area of ​​the sensitive region is 9.0 mm × 9.0 mm. The sensitive region is the surface of the entire complementary open-ring resonator.

[0063] The method for preparing the sensitive circuit board includes:

[0064] Step 1: Determine the size of the complementary open-ring resonator according to the required frequency band.

[0065] Step 2: Select a suitable half-mode SIW circuit size structure according to the size of the resonator.

[0066] Step 3: Print the actual circuit layout on a film to obtain a circuit mask;

[0067] Step 4: Lay the circuit mask plate on the circuit board with the photosensitive film on both sides and expose it for 35-40 seconds to obtain the transferred circuit board;

[0068] Step 5: Develop, etch and demould the transferred circuit board, then clean and dry it;

[0069] Step 6: Solder a high-frequency signal connector at the port of the circuit board to obtain a sensitive circuit board.

[0070] In the present invention, as a preference, the upper and lower surfaces of the substrate 120 are covered with metal layers, serving as the top wall 130 and the bottom wall 110 of the waveguide respectively. A metal via 160 is formed on one side of the top wall 130, the bottom wall 110 and the substrate 120 to act as the side wall of the waveguide, thereby forming a closed waveguide structure within the substrate 120 to restrict the propagation of electromagnetic waves within the substrate. An improved complementary split-ring resonator 150 is etched on the top of the substrate integrated waveguide circuit through printed circuit board (PCB) technology. The complementary split-ring resonator 150 is coupled with the substrate integrated waveguide circuit structure, causing a strong resonance response in the evanescent mode band of the substrate integrated waveguide circuit for electromagnetic waves, and then generating a passband before the cut-off frequency, such that the sensor has a strong response to signals within a specific frequency range. The zigzag folded slotted area of the complementary split-ring resonator 150 is the sensitive area of the circuit, that is, the electromagnetic field convergence area that can cause changes in the microwave parameters of the device. A metal-organic framework material is coated on the electric field aggregation area. The microwave sensor is mainly sensitive to dielectric properties. When a gas adsorbs onto the surface of the sensitive material, the dielectric properties (dielectric constant / permittivity) of the material will change.

[0071] The present invention also provides a preparation method for a half-mode substrate integrated waveguide type microwave gas sensing system based on a metal-organic framework. Using the half-mode substrate integrated waveguide type microwave gas sensor provided by the present invention, it includes:

[0072] Step 1: Except for the sensitive material layer, the remaining areas on the half-mode substrate integrated waveguide type microwave gas sensor are subjected to insulation and waterproof treatment, and the exposed parts are subjected to impurity removal treatment;

[0073] Step 2: Prepare a methanol solution containing the metal-organic framework SIFSIX-1-Cu and evenly brush it within the sensitive area on the surface of the circuit board to form a sensitive layer;

[0074] Step 3: After the sensitive layer dries naturally, the entire half-mode substrate integrated waveguide type microwave gas sensor is placed in a sealed gas chamber and connected to a vector network analyzer, a computer, and a humidification system to form a complete microwave sensing system.

[0075] Among them, the two ports of the circuit are located on both sides of the circuit board and are connected to the vector network analyzer through two coaxial cables to perform real-time testing on the microwave signals transmitted in the half-mode SIW microwave sensor. By analyzing the influence of the gas on the microwave signals (such as frequency, amplitude, phase changes, etc.), the measurement of the gas type and concentration is achieved.

[0076] In the present invention, as a preference, the particle size of the metal-organic framework SIFSIX-1-Cu is: 10 - 15 μm. Using an agate mortar for slight grinding, 50 mg of the ground SIFSIX-1-Cu powder is mixed with 0.2 ml of methanol (99.5%, AR) to form a slurry, and the thickness of the sensitive layer after natural drying is about 0.2 mm.

[0077] The present invention also provides a half-mode substrate integrated waveguide type microwave gas sensing system based on a metal-organic framework. Using the prepared half-mode substrate integrated waveguide type microwave gas sensing system based on a metal-organic framework, various concentrations and various gases are detected.

[0078] Electromagnetic field simulation

[0079] As Figure 5 shown, in the present invention, as a preference, the Ansys HFSS software is used to simulate the electric field and magnetic field distributions of the half-mode SIW-MCSRR microwave sensor at the resonant frequency, so as to determine the sensitive area of the circuit. Strong electric fields exist in regions of high charge density, and strong magnetic fields exist in regions of high current density. As Figure 5 can be seen, the electric field of this sensor is stronger than the magnetic field, indicating that the sensor has strong dielectric sensitivity. Coating the material at the entire circuit position will mainly interact with the electric field, generating a capacitance effect.

[0080] The working process of the half-mode substrate integrated waveguide type microwave gas sensor based on a metal-organic framework includes:

[0081] Step 1: Place the microwave gas sensor in an empty gas chamber, and use a vector network analyzer to collect the real-time scattering parameter S 21(air) ;

[0082] Step 2: Inject the target gas into the gas chamber, and collect the real-time scattering parameter S 21(target gas) ;

[0083] Step 3: Obtain the response of the microwave gas sensor in the target gas according to the scattering parameter S 21(air) in the air and the scattering parameter S 21(target gas) in the target gas.

[0084] Among them, the response of the microwave gas sensor in the target gas satisfies:

[0085] Response = ΔS 21 = S 21(air) - S 21(target gas) ;

[0086] In the formula, ΔS 21 is the response of the microwave gas sensor; S 21(air) is the scattering parameter in air; S 21(target gas) is the scattering parameter in the target gas.

[0087] Step 4: Compare the response of the microwave gas sensor in the target gas with the standard curve of the target gas concentration-response value to obtain the content of the target gas in the atmosphere.

[0088] The acquisition of the standard curve of the target gas concentration-response value includes the following process:

[0089] Inject target gases with different concentrations into the empty gas chamber in sequence, and collect the real-time scattering parameter S 21 of the microwave gas sensor in the target gases with different concentrations. According to S 21(air) in air and S 21(target gas) in the target gases with different concentrations, obtain the response value ΔS 21 of the microwave gas sensor in the target gases with different concentrations, and plot the different target gas concentrations against the corresponding responses of the microwave gas sensor to obtain the standard curve of the target gas concentration-response value.

[0090] As Figures 9 - 10 shown, it shows the S 21 and ΔS 21 response curves of the microwave gas sensor to SO2 of 10 ppb - 1000 ppm at room temperature. As the concentration of SO2 increases, the S 21 value of the sensor continuously decreases, and the response gradually increases. It can be seen from the figure that the detection limit of the sensor is as low as 10 ppb.

[0091] As Figure 11 shown, it is a comparison diagram of the response values of the microwave gas sensor to 7 different gases at 200 ppb at room temperature. It can be seen from the figure that the sensor has the highest response value to 200 ppb SO2.

[0092] The present invention utilizes the high selectivity and porous adsorption of MOFs, the low loss and high Q value of the SIW structure, the resonant characteristics of MCSRR and the concentrated electromagnetic field distribution, as well as the special detection mechanism of the microwave sensor by tracking the change of the dielectric constant to achieve high-precision detection of specific gases at room temperature.

[0093] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the examples shown and described herein.

Claims

1. A half-mode substrate integrated waveguide based microwave gas sensor using metal-organic frameworks, characterized in that, Comprising: Substrate; Bottom wall, which covers and is disposed on the lower surface of the substrate; Top wall, which is disposed on the upper surface of the substrate; Complementary split-ring resonator, which is in a zigzag structure and etched at the middle position of the top wall; Sensitive material layer, which covers the complementary split-ring resonator; The sensitive material layer is a metal-organic framework material, the materials of the top wall and the bottom wall are copper, and the substrate is a high-frequency dielectric board; Multiple vias, which are respectively and correspondingly opened on the substrate, the bottom wall and the top wall; Wherein, the multiple vias act as the side walls of a waveguide on the substrate, and the vias on the other side are replaced by equivalent magnetic walls, so as to form a closed waveguide structure on the substrate together with the top wall and the bottom wall.

2. The semi-mode substrate integrated waveguide type microwave gas sensor based on metal-organic framework according to claim 1, characterized in that, The metal-organic framework material is SIFSIX-1-Cu.

3. The semi-mode substrate integrated waveguide type microwave gas sensor based on metal-organic framework according to claim 2, wherein, The substrate and the bottom wall have the same structure, both are quadrilateral structures with dimensions of 24.0 mm × 55.0 mm.

4. The semi-mode substrate integrated waveguide type microwave gas sensor based on metal-organic framework according to claim 3, wherein The middle of the top wall is a square structure, and both ends are strip-like structures extending outwards.

5. The semi-mode substrate integrated waveguide type microwave gas sensor based on metal-organic framework according to claim 4, characterized in that The multiple vias are all circular structures and are respectively and equally spaced on one side of the top wall, the substrate and the bottom wall.

6. The semi-mode substrate integrated waveguide type microwave gas sensor based on metal-organic framework according to claim 5, characterized in that, The sensitive material layer is a square structure with dimensions of: 9.0 mm × 9.0 mm.

7. A preparation method of a semi-mode substrate integrated waveguide type microwave gas sensing system based on metal-organic frameworks, characterized in that, Using the half-mode substrate integrated waveguide type microwave gas sensor based on metal-organic framework according to any one of claims 1-6, comprising: Step 1, perform insulation and waterproof treatment on all areas of the half-mode substrate integrated waveguide type microwave gas sensor except the complementary split-ring resonator area, and perform impurity removal treatment on the exposed part; Step 2, prepare a methanol solution containing SIFSIX-1-Cu, and quickly and evenly apply it to the sensitive area to form a sensitive layer; Step 3, after the sensitive layer is naturally dried, put the whole half-mode substrate integrated waveguide type microwave gas sensor into a sealed gas chamber, and connect it to a vector network analyzer, a computer and a humidification system to form a complete microwave sensing system.

8. The preparation method of the metal-organic framework-based semi-substrate integrated waveguide type microwave gas sensing system according to claim 7, characterized in that The metal-organic framework SIFSIX-1-Cu is ground using an agate mortar, and the particle size is 10-15 μm.

9. The preparation method of the metal-organic framework-based half-mode substrate integrated waveguide type microwave gas sensing system according to claim 8, characterized in that, In the methanol solution containing SIFSIX-1-Cu, the mass of SIFSIX-1-Cu is 50 mg, the mass fraction of the methanol solution is 99.5%, and the thickness of the sensitive layer after natural drying is 0.2 mm.

10. Application of a semi-mode substrate integrated waveguide type microwave gas sensing system based on metal-organic framework, characterized in that, Using the half-mode substrate integrated waveguide type microwave gas sensing system based on metal-organic framework prepared according to claim 9, detect various concentrations and various gases.

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