Artificial magnetic conductor antenna ethanol gas sensor based on sputtering ZnO sensitive film

Abstract

The invention discloses an artificial magnetic conductor antenna ethanol gas sensor based on a sputtered ZnO sensitive film, which comprises an antenna and an artificial magnetic conductor, the antenna is located at the central position of one surface of the artificial magnetic conductor, and the antenna is not contacted with the artificial magnetic conductor; the antenna comprises a first dielectric substrate, a metal radiation patch, a first metal grounding plate and a zinc oxide sensitive film, the metal radiation patch and the first metal grounding plate are connected to the two opposite faces of the first dielectric substrate respectively, and the zinc oxide sensitive film is formed on the face, away from the first dielectric substrate, of the metal radiation patch. The sensitivity of the artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film reaches up to 2.24 kHz / ppm, the maximum transmission distance is 20 m under the condition that the concentration of ethanol gas is 2500 ppm, real-time signal transmission can be conducted, remote wireless monitoring of high-concentration ethanol gas is achieved, and good stability is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of wireless sensors, and in particular relates to an artificial magnetic conductor antenna ethanol gas sensor based on a sputtered ZnO sensitive film. Background Art

[0002] As a colorless gas, ethanol gas is flammable and explosive when mixed with air in the presence of high heat energy. As a volatile organic compound (VOCs), ethanol gas is widely present in food safety, health care, fuel processing, human living environment and physical health. Long-term exposure to high concentrations of ethanol gas can cause a variety of diseases, such as damage to the respiratory system, asthma, heart disease, stroke, cancer, and even irreversible damage.

[0003] As a new type of wireless communication device, artificial magnetic conductor antenna sensor realizes miniaturization, high sensitivity, and remote wireless monitoring of ethanol gas. Most ethanol gas sensors (a type of artificial magnetic conductor antenna sensor) need to work at high temperature. A few ethanol gas sensors can work at room temperature, but their sensitivity is low. It is still a challenge to develop a sensor that can accurately detect ethanol gas concentration at room temperature. Reference "Facilesynthesis of W 18 O 49 / Graphene nanocomposites for highly sensitive ethanol gas sensors” Using a quartz crystal resonator (QCR) in series with digital inter-electrodes (IDEs) coated with ZnO / WSe2 nanocomposite films, a low-cost room-temperature ethanol gas sensor with slightly improved sensitivity was proposed, but its maximum detection concentration was 300ppm and the detection range was small. Therefore, it is promising to develop an artificial magnetic conductor antenna sensor with high sensitivity, miniaturization, fast response / recovery time, long-term stability, and remote wireless monitoring of ethanol gas at room temperature. Summary of the invention

[0004] In view of the deficiencies in the prior art, the object of the present invention is to provide an artificial magnetic conductor antenna ethanol gas sensor based on a sputtered ZnO sensitive film.

[0005] The purpose of the present invention is achieved through the following technical solutions.

[0006] An artificial magnetic conductor antenna ethanol gas sensor based on a sputtered ZnO sensitive film comprises: an antenna and an artificial magnetic conductor, wherein the antenna is located at the center of one side of the artificial magnetic conductor, and the antenna and the artificial magnetic conductor are not in contact;

[0007] The antenna comprises: a first dielectric substrate, a metal radiation patch, a first metal grounding plate and a zinc oxide sensitive film. The metal radiation patch and the first metal grounding plate are respectively connected to two opposite surfaces of the first dielectric substrate. The zinc oxide sensitive film is formed on a surface of the metal radiation patch away from the first dielectric substrate.

[0008] In the above technical solution, the metal radiation patch includes: three branch radiation patches and one connecting radiation patch, each branch radiation patch includes: a first square patch and a first rectangular patch connected to one side edge of the first square patch;

[0009] The connected radiation piece includes: a second square patch, a second rectangular patch and a third rectangular patch, the top edge of the second rectangular patch is connected to the bottom edge of the second square patch, the bottom edge of the second rectangular patch is connected to the top edge of the third rectangular patch, and the top edge, the left edge and the right edge of the second square patch are respectively connected to an edge of the first rectangular patch of a branch radiation piece;

[0010] The metal radiation patch is symmetrical along the center line of the second rectangular patch in the length direction.

[0011] In the above technical solution, the zinc oxide sensitive film is formed by magnetron sputtering.

[0012] In the above technical solution, the method for preparing the zinc oxide (ZnO) sensitive film comprises: sending the metal radiation patch into the chamber of the ultra-high altitude radio frequency magnetron sputtering equipment, and evacuating the vacuum to 1.0×10 -4 ~6.0×10 -4 Pa, introduce argon (Ar) into the chamber, turn on the RF source for controlling the ignition of the ZnO target, adjust the RF source power to 100-105W, make the ZnO target ignite, pre-sputter for 15-20min at a power of 100-105W, and then formally sputter for 15-30min at a power of 100-105W to obtain a zinc oxide (ZnO) sensitive film.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The surface of the metal radiation patch of the present invention is sputtered with a ZnO sensitive film. Under room temperature conditions, the sensitivity of the artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film of the present invention is as high as 2.24kHz / ppm. When the concentration of ethanol gas is 2500ppm, the maximum transmission distance is 20m. It can perform real-time signal transmission, realize remote wireless monitoring of high-concentration ethanol gas, and has good stability.

[0015] 2. The artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film of the present invention can detect 0 to 5100 ppm of ethanol gas and has a wide detection range.

[0016] 3. The present invention introduces an artificial magnetic conductor on the basis of the antenna, which can increase the radiation gain of the antenna and improve the sensitivity of testing ethanol gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 (a) front view and (b) top view of the artificial magnetic conductor antenna ethanol gas sensor based on sputtered ZnO sensitive film;

[0018] Figure 2 (a) and Figure 2 (b) is a dimensional diagram of the metal radiation patch of the artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film;

[0019] Figure 3 The dimension diagram of the first metal ground plate of the artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film;

[0020] Figure 4 (a) and Figure 4 (b) is a dimensional diagram of the AMC unit of the artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film;

[0021] Figure 5 The return loss test diagrams of Example 2, Example 5 and Example 6;

[0022] Figure 6 (a) is the gain diagram of the antenna ethanol gas sensor (Antenna), Figure 6 (b) is the electric field current diagram of the antenna ethanol gas sensor (Antenna), Figure 6 (c) is the gain diagram of the artificial magnetic conductor antenna ethanol gas sensor (Antennawith AMC), Figure 6 (d) is the electric field current diagram of the artificial magnetic conductor antenna ethanol gas sensor (Antenna with AMC);

[0023] Figure 7 The straight line is the fitting line of the artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film prepared in Example 2;

[0024] Figure 8 (a) is the frequency and signal strength changes of the artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film prepared in Example 2 and the handheld spectrum analyzer at different distances. Figure 8 (b) is Figure 8 (a) Photo of the test site;

[0025] Fig. 9(a) is the signal strength of the artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film prepared in Example 2 under different obstacles, Fig. 9 (b) is a photo of the test site without obstacles;

[0026] Fig.10 Schematic diagram of detecting ethanol gas concentration in an ultra-clean room. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0028] In the following embodiment, the first dielectric substrate adopts a FR4 substrate with a dielectric constant of 4.6 and a thickness of 1 mm, and the length and width of the first dielectric substrate are both 30 mm. The second dielectric substrate adopts a FR4 substrate with a dielectric constant of 4.7 and a thickness of 1 mm, and the length and width of the second dielectric substrate are both 60 mm. The first metal ground plate and the second metal ground plate both adopt copper foil with a thickness of 0.1 mm.

[0029] The detection of ethanol gas concentration in the following examples was carried out at room temperature.

[0030] Embodiments 1 to 4

[0031] like Figures 1 to 4 As shown, an artificial magnetic conductor antenna ethanol gas sensor (Antenna with AMC / ZnO) based on a sputtered ZnO sensitive film includes: an antenna 1 and an artificial magnetic conductor 2, the antenna 1 is located at the center of one side of the artificial magnetic conductor 2, the antenna 1 and the artificial magnetic conductor 2 are not in contact, the antenna 1 and the artificial magnetic conductor 2 are bonded and connected by a foam material (not shown in the figure), the cross-sectional area of ​​the antenna 1 is 1 / 4 of the artificial magnetic conductor 2, and the thickness of the foam material is 18.5 mm. The foam material is polyvinyl chloride.

[0032] The antenna 1 includes: a first dielectric substrate 1-1, a metal radiation patch 1-2, a first metal ground plate and a zinc oxide (ZnO) sensitive film. The metal radiation patch 1-2 and the first metal ground plate are respectively connected to two opposite surfaces of the first dielectric substrate 1-1, and the zinc oxide (ZnO) sensitive film is formed (sputtered) on a surface of the metal radiation patch 1-2 away from the first dielectric substrate 1-1.

[0033] like Figure 2 As shown, the metal radiation patch 1-2 includes: three branch radiation patches and one connecting radiation patch, each branch radiation patch includes: a first square patch and a first rectangular patch connected to an edge of one side of the first square patch;

[0034] The connected radiation piece includes: a second square patch, a second rectangular patch and a third rectangular patch. The top edge of the second rectangular patch is connected to the bottom edge of the second square patch, the bottom edge of the second rectangular patch is connected to the top edge of the third rectangular patch, and the top edge, left edge and right edge of the second square patch are each connected to an edge of the first rectangular patch of a branch radiation piece.

[0035] The first square patch and the second square patch are in the shape of squares, and the first rectangular patch, the second rectangular patch and the third rectangular patch are in the shape of rectangles. The side length of the first square patch is b1=8mm, the length of the first rectangular patch is b4=3.5mm, the width of the first rectangular patch is b2=3mm, and the shorter edge of the first rectangular patch is used to connect with the first square patch, so that the two opposite shorter edges of each first rectangular patch are respectively connected to the second square patch and the first square patch.

[0036] The side length of the second square patch is b2=3mm, the length of the second rectangular patch is b5=11mm, the width of the second rectangular patch is 1.4mm, and the shorter edges of the second rectangular patch are the top and bottom edges of the second rectangular patch. The length of the third rectangular patch is b6=3mm, the width of the third rectangular patch is b7=2.5mm, and the longer edges of the third rectangular patch are the top and bottom edges of the third rectangular patch.

[0037] The metal radiation patch 1-2 is symmetrical along the center line of the second rectangular patch in the length direction.

[0038] like Figure 2 (a) and Figure 2 As shown in (b), the dimensions of the metal radiation patch 1-2 are: b1=8mm, b2=3mm, b3=4.3mm, b4=3.5mm, b5=11mm, b6=3mm, b7=2.5mm.

[0039] After arranging three hollows on the third square patch, a first metal grounding plate is formed. The three hollows are the first hollow, the second hollow and the third hollow. The first hollow and the second hollow are respectively outline hollows. The first hollow is located at the left edge of the third square patch, and the second hollow is located at the right edge of the third square patch. The shapes of the first hollow and the third hollow are respectively square, and the shape of the second hollow is rectangular. The side length of the third square patch is 30 mm, the side length of the third hollow is a8=5.3 mm, the side length of the first hollow is a3=12.1 mm, and the length of the second hollow is 14.5 mm and the width is a6=7.9 mm. The first hollow is located on one side of the longitudinal edge (longer side) of the second hollow. The distance between the top edge of the first hollow and the top edge of the third square patch is a1=7.9 mm, and the distance between the top edge of the second hollow and the top edge of the third square patch is a2=7 mm. The distance between the left edge of the third hollow and the right edge of the first hollow is a9=1.6mm, the distance between the right edge of the third hollow and the left edge of the second hollow is a7=3.1mm, and the distance between the top edge of the third hollow and the top edge of the third square patch is 7mm.

[0040] like Figure 3 As shown, the dimensions of the first metal ground plate are: a1=7.9 mm, a2=7 mm, a3=12.1 mm, a4=10 mm, a5=8.5 mm, a6=7.9 mm, a7=3.1 mm, a9=1.6 mm, a8=5.3 mm;

[0041] The artificial magnetic conductor 2 includes: a second dielectric substrate 2-1, a second metal ground plate (not shown in the figure) and an AMC unit array 2-2. The AMC unit array 2-2 and the second metal ground plate are respectively connected to two opposite surfaces of the second dielectric substrate 2-1. The AMC unit array 2-2 is close to the antenna 1 and the second metal ground plate is far away from the antenna 1. The AMC unit array 2-2 is four AMC units arranged in a 2×2 matrix, and the second metal ground plate is a 60mmx60mm copper foil.

[0042] Each AMC unit includes: a fourth rectangular patch and two fifth rectangular patches, the longer side of the fourth rectangular patch is vertically arranged, the length of the fourth rectangular patch is 29mm, the width is n5=18.6mm, and the fourth rectangular patch is connected to the longer side of a fifth rectangular patch on each of its two edges along the length direction, so that the outer contour of the AMC unit forms a "cross", and the length of the fifth rectangular patch is n6=14mm and the width is 5.2mm. Four first triangular hollows are formed at the center of the fourth rectangular patch, each of which is an isosceles right triangle, and the right angles of the four first triangular hollows face the center of the fourth rectangular patch, and the two right angles of each first triangular hollow are respectively arranged horizontally and vertically. The distance between the right angles of the two first triangular hollows arranged in the horizontal direction and close to each other is g1=1.66mm, and the distance between the right angles of the two first triangular hollows arranged in the vertical direction and close to each other is g1=1.66mm.

[0043] Two second triangular hollows are formed on each fifth rectangular patch, each second triangular hollow is an isosceles right triangle, the hypotenuse of each second triangular hollow faces the center of the fourth rectangular patch, and the two right-angled sides of each second triangular hollow are respectively set horizontally and vertically.

[0044] Two third triangular hollows are formed at the upper and lower parts of the fourth rectangular patch, each of which is an isosceles right triangle. The hypotenuse of each third triangular hollow faces the center of the fourth rectangular patch, and the two right-angled sides of each third triangular hollow are respectively set horizontally and vertically.

[0045] Each AMC unit is symmetrically arranged along the horizontal center line and the vertical center line.

[0046] The shape of the first triangular hollow is the same as that of the second triangular hollow. The distance between the horizontal right-angled side of the second triangular hollow on the top and the top edge of the fifth rectangular patch is n7 = 3.02 mm. The right-angled side of the second triangular hollow is 7.2 mm. The distance between the vertical right-angled side of the second triangular hollow on the right and the right edge of the fifth rectangular patch is 0.93 mm.

[0047] The distance between the horizontal right-angled side of the third triangular hollow on the top and the top edge of the fourth rectangular patch is n3 = 0.56 mm. The distance between the vertical right-angled side of the third triangular hollow on the right and the right edge of the fourth rectangular patch is g2 = 1.69 mm.

[0048] like Figure 4 (a) and Figure 4As shown in (b), the dimensions of the AMC unit are: n1=3.2mm, n8=3.2mm, n2=7.2mm, n4=7.2mm, n5=18.6mm, n6=14mm, n7=3.02mm, n3=0.56mm, g2=1.69mm, g1=1.66mm.

[0049] The method for preparing the zinc oxide (ZnO) sensitive film includes: feeding the pretreated copper foil (metal radiation patch, thickness of 0.1 mm) into the chamber of the ultra-high altitude radio frequency magnetron sputtering equipment (JGP450), and fixing the ZnO target in the chamber (it should be noted that the screws for fixing should not be tightened too much, and it is best to loosen them slightly), and evacuating to 1.0×10 -4 Pa, turn on the vacuum gauge, then start the mechanical pump to start extracting the air in the cavity, when the speed reaches 36000r / min, introduce argon (Ar) into the chamber (the flow rate of Ar is 30sccm, and the pressure is controlled to 1.0Pa), turn on the RF source for controlling the ignition of the ZnO target, adjust the RF source power to 100W, so that the ZnO target is ignited, pre-sputter for 15min at 100W power, and then formally sputter for Xmin at 100W power to obtain a zinc oxide (ZnO) sensitive film, wherein the pretreatment method includes: first using fine sandpaper to polish the oxide layer on the surface of the copper foil, placing it in a 30mL beaker after polishing, and adding 15mL of anhydrous ethanol to the beaker at the same time, using anhydrous ethanol for ultrasonic treatment (ultrasonic frequency of 40kHz, ultrasonic time of 5min, gently clamped with pointed tweezers, and dried under an infrared lamp with a power of 375W for 10min to obtain the pretreated copper foil.

[0050] The X values ​​are shown in Table 1.

[0051] Table 1

[0052] Zinc oxide (ZnO) sensitive film X(min) Example 1 15 Example 2 20 Example 3 25 Example 4 30

[0053] Example 5

[0054] An antenna ethanol gas sensor (Antenna) is basically the same as Example 2, except that the antenna ethanol gas sensor of Example 5 does not contain an artificial magnetic conductor and the antenna ethanol gas sensor of Example 5 is not sputtered with a zinc oxide (ZnO) sensitive film.

[0055] Example 6

[0056] An artificial magnetic conductor antenna ethanol gas sensor (Antenna with AMC) is basically the same as Example 2, except that the artificial magnetic conductor antenna ethanol gas sensor of Example 6 is not sputtered with a zinc oxide (ZnO) sensitive film.

[0057] The return loss test was performed using the artificial magnetic conductor antenna ethanol gas sensor (Antennawith AMC / ZnO) based on the sputtered ZnO sensitive film of Example 2, the antenna ethanol gas sensor (Antenna) of Example 5, and the artificial magnetic conductor antenna ethanol gas sensor (Antenna with AMC) of Example 6. The test results are as follows: Figure 5 As shown, Figure 5 There are three sets of "Antenna with AMC / ZnO" data, which means that two more artificial magnetic conductor antenna ethanol gas sensors based on sputtered ZnO sensitive film are prepared, which are the same as those in Example 2. A total of three Antenna with AMC / ZnO are tested once each to verify their stability. Figure 5 It can be seen that the frequencies of the three sets of “Antenna with AMC / ZnO” vary between 2.481 and 2.482 GHz, which is very stable.

[0058] Figure 6 (a) is the gain diagram of Antenna. Figure 6 (b) is the electric field current diagram of Antenna, Figure 6 (c) is the gain diagram of Antenna with AMC. Figure 6 (d) is the electric field current diagram of Antenna with AMC. The gain and current density of the antenna ethanol gas sensor (Antenna) in Example 5 and the artificial magnetic conductor antenna ethanol gas sensor (Antenna with AMC) in Example 6 were simulated using HFSS software. The gain of Antenna and Antenna with AMC were 1.83 dB (as shown in Figure 2). Figure 6 a) and 4.19dB (as shown in Figure 6 The current density of Antenna and Antenna with AMC is 180A / m (as shown in c). Figure 6 b) and 220A / m (as shown in Figure 6 As shown in d), the electric field and current distribution of Antenna with AMC are enhanced. The gain of Antenna with AMC is more than doubled compared with Antenna, which increases the radiation capability. This shows that artificial magnetic conductors can improve the performance of antennas.

[0059] In the ethanol gas concentration range of 0 to 5100 ppm, the frequency offset of the sensor testing different concentrations of ethanol was obtained, fitted into a straight line, and then the sensitivity was calculated (the calculation method of the sensitivity refers to Yu, X (Yu, Xiang); chen, XD (chen, Xiangdong); Ding, X (Ding, Xing); Tang, K (Tang, Kun); Zhao, X (Zhao, Xuan); Liu, F (Liu, Fang), DOI: 10.1016 / j.snb.2023.133530). The artificial magnetic conductor antenna ethanol gas sensor (Antenna with AMC / ZnO) based on the sputtered ZnO sensitive film prepared in Examples 1 to 4, the antenna ethanol gas sensor (Antenna) prepared in Example 5, and the artificial magnetic conductor antenna ethanol gas sensor (Antenna with AMC) prepared in Example 6 were used as sensors for sensitivity testing, as shown in Table 3.

[0060] The straight line fitting of Example 2 is as follows Figure 7 shown.

[0061] Table 3

[0062] Example Sensitivity (kHz / ppm) Example 1 1.09 Example 2 2.24 Example 3 1.55 Example 4 1.21 Example 5 0.682 Example 6 1.03

[0063] The frequency offset of the artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film prepared in Example 2 is 10.62 MHz, R 2 =0.968, the frequency offset of the artificial magnetic conductor antenna ethanol gas sensor based on sputtered ZnO sensitive film prepared in Example 2 is the largest, with a sensitivity of 2.24kHz / ppm. Compared with Antenna with AMC, the sensitivity of the artificial magnetic conductor antenna ethanol gas sensor based on sputtered ZnO sensitive film prepared in Example 2 is nearly doubled (the frequency offset of the antenna ethanol gas sensor (Antenna) prepared in Example 5 is 3.12MHz and the frequency offset of the artificial magnetic conductor antenna ethanol gas sensor (Antenna with AMC) prepared in Example 6 is 5.62MHz).

[0064] like Figure 7 As shown, through Figure 7 The fitting linear equation of the artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film prepared in Example 2 is obtained by fitting into a straight line:

[0065] Δf=(298±318)+(-2.24±0.105)C EtOH , where Δf is the frequency offset, C EtOHis the concentration of ethanol gas, and the maximum value of Δf is taken as the calculation result of the frequency offset.

[0066] The artificial magnetic conductor antenna ethanol gas sensor based on sputtered ZnO sensitive film prepared in Example 2 was connected to a power source, and the effect of different distances between it and a handheld spectrum analyzer on the sensitivity was tested. The frequency of the handheld spectrum analyzer was controlled at about 2.475 GHz, and the concentration of ethanol gas in the environment where the artificial magnetic conductor antenna ethanol gas sensor was located was set to 2500 ppm. The distance between the artificial magnetic conductor antenna ethanol gas sensor based on sputtered ZnO sensitive film (Antenna with AMC / ZnO) and the handheld spectrum analyzer was adjusted within a range of 1 to 20 meters, as shown in FIG. Figure 8 (a) and Figure 8 As shown in (b), as the distance increases from 1 meter to 20 meters, the signal strength of the Antenna with AMC / ZnO prepared in Example 2 decreases from -61.1 dBm to -93.1 dBm. As the distance increases further, no signal will be generated. Therefore, the maximum transmission distance of the artificial magnetic conductor antenna ethanol gas sensor is 20 meters. However, as the distance increases from 1 meter to 20 meters, the frequency remains approximately unchanged, indicating that the sensitivity of the Antenna with AMC / ZnO is not affected by the distance and has a good ability to transmit signals.

[0067] The artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film prepared in Example 2 was connected to a power supply, and an obstacle was set between the artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film and the handheld spectrum analyzer (the distance between the artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film and the handheld spectrum analyzer was 1.6 m), and the signal strength under different obstacles was tested ( Fig. 9 (b) is a photo of the test without obstacles), the obstacle is one of the following: plastic board (thickness: 0.3cm), iron box (thickness: 12cm), bushes (thickness: 80cm), concrete (thickness: 120cm), glass (thickness: 0.2cm), foam (thickness: 12cm), and wooden board (thickness: 1.2cm) (thickness: the length of the obstacle in the direction of the connection between the artificial magnetic conductor antenna ethanol gas sensor and the handheld spectrum analyzer).

[0068] Since electromagnetic waves have the ability to penetrate, they will produce different signal strengths when passing through obstacles made of different materials. Fig. 9As shown in (a), when the obstacle is a plastic board, glass, foam, or wooden board, the signal strength is relatively strong; when the obstacle is concrete or bushes, the electromagnetic wave penetration ability is weakened; when the obstacle is an iron box, the electromagnetic wave has a skin effect on the conductor such as the iron box, and the current is only distributed in a very thin layer on the surface of the conductor. When the electromagnetic wave is incident on the iron box, a large part of the incident electromagnetic wave is reflected due to impedance mismatch. At this time, the electromagnetic field incident on the conductor is weak.

[0069] In order to evaluate the potential application of artificial magnetic conductor antenna ethanol gas sensor based on sputtered ZnO sensitive film, remote wireless monitoring of ethanol gas in an ultra-clean room was carried out. Fig.10 As shown, the artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film prepared in Example 2 ( Fig.10 The "artificial magnetic conductor antenna sensor" in the ultra-clean room is connected to a power supply and placed in an ultra-clean room. The handheld spectrum analyzer with a receiving antenna is placed outside the ultra-clean room. The distance between the handheld spectrum analyzer and the artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film is 6m. There is a glass door (total thickness of 8cm) between the handheld spectrum analyzer and the artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film. When the concentration of ethanol gas in the ultra-clean room is 1500ppm, the measured frequency offset is 3180kHz / ppm, and the signal strength reaches -74.3dBm. According to the above-mentioned fitted linear equation, it can be calculated that when the frequency offset is 3180kHz / ppm, the concentration of ethanol gas is 1498.83ppm, and the calculated result is that 1498.83ppm is approximately consistent with 1500ppm. This shows that the artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film has the ability to remotely and accurately monitor ethanol gas.

[0070] During the above-mentioned ethanol gas concentration test (ethanol gas concentration is 0-5100 ppm), the average response time of the artificial magnetic conductor antenna ethanol gas sensor based on the sputtered ZnO sensitive film is 37 s, and the average recovery time is 43 s.

[0071] As a unique n-type metal oxide, ZnO sensitive film has the ability to sensitively monitor the concentration of ethanol gas in the surrounding environment. When the artificial magnetic conductor antenna ethanol gas sensor based on sputtered ZnO sensitive film is exposed to ethanol environment, O2 in ZnO - The conductivity of the ZnO sensitive film changes when reacting with ethanol molecules. After the antenna absorbs a certain amount of ethanol gas, the resonant frequency decreases, which affects the resonant frequency of the antenna sensor and further improves the sensitivity. The present invention uses this feature to measure the concentration of ethanol gas in the environment.

[0072] HFSS software was used to optimize and debug multiple times. The performance indicators (return loss (S 11 ), gain, frequency, and electromagnetic field current distribution), the shapes of the antenna and artificial magnetic conductor of Example 2 are optimal.

[0073] The present invention is described above by way of example. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by those skilled in the art without inventive effort falls within the protection scope of the present invention.

Claims

1. An artificial magnetic conductor antenna ethanol gas sensor based on sputtered ZnO sensitive film, characterized in that: include: The antenna and the artificial magnetic conductor, the antenna is located at the center of one side of the artificial magnetic conductor, and the antenna and the artificial magnetic conductor are not in contact; The antenna comprises: a first dielectric substrate, a metal radiation patch, a first metal grounding plate and a zinc oxide sensitive film. The metal radiation patch and the first metal grounding plate are respectively connected to two opposite surfaces of the first dielectric substrate. The zinc oxide sensitive film is formed on a surface of the metal radiation patch away from the first dielectric substrate.

2. The artificial magnetic conductor antenna ethanol gas sensor according to claim 1, characterized in that: The metal radiation patch includes: three branch radiation patches and one connecting radiation patch, each branch radiation patch includes: a first square patch and a first rectangular patch connected to an edge of one side of the first square patch; The connected radiation piece includes: a second square patch, a second rectangular patch and a third rectangular patch, the top edge of the second rectangular patch is connected to the bottom edge of the second square patch, the bottom edge of the second rectangular patch is connected to the top edge of the third rectangular patch, and the top edge, the left edge and the right edge of the second square patch are respectively connected to an edge of the first rectangular patch of a branch radiation piece; The metal radiation patch is symmetrical along the center line of the second rectangular patch in the length direction.

3. The artificial magnetic conductor antenna ethanol gas sensor according to claim 1, characterized in that: The ZnO sensitive film is formed by magnetron sputtering.

4. The artificial magnetic conductor antenna ethanol gas sensor according to claim 1, characterized in that: The method for preparing the zinc oxide sensitive film comprises: sending the metal radiation patch into the chamber of the ultra-high altitude radio frequency magnetron sputtering equipment, evacuating the vacuum to 1.0×10 -4 ~6.0×10 -4 Pa, introduce argon gas into the chamber, turn on the RF source for controlling the ignition of the ZnO target, adjust the RF source power to 100-105W, make the ZnO target ignite, pre-sputter for 15-20min at a power of 100-105W, and then formally sputter for 15-30min at a power of 100-105W to obtain a zinc oxide sensitive film.

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