Soil moisture content detection sensor and soil moisture content measuring device

Abstract

To measure a moisture content in the soil at the desired depth with high accuracy.SOLUTION: A soil moisture content detection sensor 10 is configured by stacking a protective layer 21, a conductor mesh layer 22, a dielectric layer 23 on which a radio wave propagates, a shielding layer 24 and a protective layer 25. The shielding layer 24 is provided on one side of the dielectric layer 23 and is composed of conductive materials such as aluminum. In addition, the conductor mesh layer 22 is provided on the other side of the dielectric layer 23; only an area to which a transmission antenna and a reception antenna are attached and a sensing area are mesh-like with conductive materials; and the other area has the same shielding structure as the shielding layer 24. The protective layers 21, 25 are configured to cover the shielding layer 24 and the conductor mesh layer 22, respectively.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a soil moisture detection sensor and a soil moisture measuring device.

Background Art

[0002] When managing a field for cultivating plants such as agricultural crops, in order to grow the plants smoothly, it is necessary to adjust the moisture content in the soil to be appropriate. And if the soil moisture content of the field can be measured and an accurate value can be grasped, watering can be performed at an appropriate timing.

[0003] For example, Patent Document 1 discloses a wireless soil humidity measuring device that sets a measurement transmission antenna and a measurement reception antenna at a measurement target site, measures the intensity of the measurement radio wave received by the measurement reception antenna, and detects the humidity of the measurement target site. However, in this Patent Document 1, only the case where the measurement target site is a flower pot is shown. And in the technology disclosed in this Patent Document 1, since radio waves are propagated in the soil, the measurement accuracy deteriorates due to the influence of multipath. In particular, in the technology disclosed in Patent Document 1, when the measurement target site is actual soil instead of a flower pot, both the reception antenna and the transmission antenna need to be buried in the soil, and the radio waves also spread to the surroundings, so that the moisture content of a specific place cannot be accurately detected. Also, in the technology disclosed in Patent Document 1, since both the reception antenna and the transmission antenna need to be buried in the soil, there are problems such as generating metal corrosion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The object of the present invention is to provide a soil moisture content detection sensor and a soil moisture content measuring device that can measure the amount of moisture in the soil at a depth to be measured with high accuracy. [Means for solving the problem]

[0006] To achieve the above objective, the first embodiment of the present invention is a soil moisture content detection sensor for detecting the amount of moisture in the soil, A dielectric layer through which radio waves propagate, A shielding layer made of a conductive material is provided on one side of the dielectric layer, A mesh layer is provided on the other side of the dielectric layer, in which the area where the transmitting antenna and receiving antenna are attached and the sensing area for measuring the amount of moisture when inserted into the soil are made of a mesh made of a conductive material, and the other areas have the same shielding structure as the shield layer, The system includes a protective layer configured to cover the shield layer and the mesh layer.

[0007] Furthermore, the soil moisture content measuring device according to the second aspect of the present invention includes a transmitting antenna and Receiving antenna and A soil moisture content detection sensor comprising: a dielectric layer through which radio waves propagate; a shielding layer provided on one side of the dielectric layer and made of a conductive material; a mesh layer provided on the other side of the dielectric layer, having a mesh-like structure made of a conductive material in the area where a transmitting antenna and a receiving antenna are mounted and a sensing area for measuring moisture content when inserted into soil, and the other area having the same shielding structure as the shielding layer; and a protective layer configured to cover the shielding layer and the mesh layer. The system includes a determination unit that determines the amount of moisture in the soil adjacent to the mesh-like region of the mesh layer based on the state of the received signal received by the receiving antenna.

[0008] Furthermore, in the soil moisture content measuring device of the third aspect of the present invention, the determination unit uses the correspondence between the received signal intensity and the soil moisture content, which has been measured in advance, to determine the moisture content of the soil adjacent to the sensing area of ​​the mesh layer as the amount of moisture in the soil, based on the received signal intensity in the received signal.

[0009] Furthermore, in the fourth aspect of the present invention, the soil moisture content measuring device uses a learning model generated by machine learning using previously measured soil moisture content and channel state information as training data, to determine the moisture content of soil adjacent to the sensing area of ​​the mesh layer as the amount of moisture in the soil from the channel state information in the received signal. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a soil moisture content detection sensor and a soil moisture content measuring device that can measure the amount of moisture in the soil at a depth to be measured with high accuracy. [Brief explanation of the drawing]

[0011] [Figure 1] This is a perspective view of a typical 2D communication sheet 100. [Figure 2] This is a cross-sectional view of the two-dimensional communication sheet 100 shown in Figure 1. [Figure 3] This figure shows the appearance of a soil moisture content detection sensor 10 used in a soil moisture content measuring device according to one embodiment of the present invention. [Figure 4] Figure 3 is a cross-sectional view of the soil moisture content detection sensor 10. [Figure 5] This is a diagram illustrating the structure of the soil moisture content detection sensor 10. [Figure 6] This diagram illustrates the configuration of a soil moisture content measuring device using a soil moisture content detection sensor 10. [Figure 7] This diagram shows the functional block configuration of the moisture content determination device 50. [Figure 8] This figure shows an example of data illustrating the relationship between soil moisture content and RSSI. [Figure 9]FIG. is a diagram showing a modified example of the soil moisture detection sensor 10A which is a modified example of the soil moisture detection sensor 10 in one embodiment of the present invention. [Figure 10] FIG. is a diagram showing a modified example of the soil moisture detection sensor 10B which is a modified example of the soil moisture detection sensor 10 in one embodiment of the present invention. [Figure 11] It is a flowchart for explaining the flow of processing for measuring the moisture content in soil based on CSI data using machine learning. [Figure 12] FIG. is a diagram showing an example of a system configuration when CSI data acquired by the moisture content determination device 50 is transmitted to the server device 74 on the cloud service for processing.

MODE FOR CARRYING OUT THE INVENTION

[0012] Next, embodiments of the present invention will be described in detail with reference to the drawings.

[0013] The soil moisture measurement device of the present embodiment uses a two-dimensional communication technology using a planar communication medium called a two-dimensional communication sheet. Therefore, before explaining the soil moisture measurement device of the present embodiment, this two-dimensional communication technology will be explained. <00E0092>

[0014] FIG. 1 shows a perspective view of a general two-dimensional communication sheet 100, and FIG. 2 shows a cross-sectional view of the two-dimensional communication sheet 100.

[0015] As shown in FIG. 2, when the surface for inputting and outputting electromagnetic waves is defined as the front surface, the two-dimensional communication sheet 100 has a structure in which a protective layer 101, a conductor mesh layer 102 forming a mesh-like conductor wiring, a dielectric layer 103, a shield layer 104 in which the entire sheet is a conductor, and a protective layer 105 on the back surface are sequentially laminated.

[0016] For the dielectric layer 103, resin materials or rubber materials are used, and materials with lower dielectric constant and electrostatic loss tangent (tanδ) are more suitable because they have better transmission characteristics. For the conductive mesh layer 102 and shielding layer 104, materials used in wiring materials such as aluminum, copper, and silver are suitable. In this case, the grid shape of the conductive mesh layer 102 has an optimal wiring pattern (line width, line pitch) depending on the sheet characteristics including thickness and size, and the characteristics of the dielectric material used for the dielectric layer 103. Therefore, the wiring pattern of the conductive mesh layer 102 is designed with the optimal line width and line pitch.

[0017] Next, we will explain the communication principle of 2D communication using this 2D communication sheet 100.

[0018] When performing two-dimensional communication, a transmitting antenna (patch antenna) 110 is placed on the surface of the two-dimensional communication sheet 100. When the transmitting antenna 110 is placed on the surface of the two-dimensional communication sheet 100, electromagnetic waves propagate inside the dielectric layer 103 due to electromagnetic coupling. In this process, a small amount of electromagnetic waves leak out onto the surface of the two-dimensional communication sheet 100. These leaked electromagnetic waves are a type of electromagnetic wave called an evanescent wave. When a receiving antenna 120 is brought close to any point on the surface of the two-dimensional communication sheet 100, communication is established due to electromagnetic coupling. Two-dimensional communication performed in this manner has the advantage that the electromagnetic wave intensity rapidly attenuates when moved a few centimeters away from the surface of the two-dimensional communication sheet 100, making it less prone to information leakage and less susceptible to radio wave interference from space. For this reason, this two-dimensional communication is used as a communication medium between devices placed on the two-dimensional communication sheet 100, and is used for communication between devices such as PCs (personal computers) and smartphones in offices.

[0019] In this two-dimensional communication, high frequencies such as 2.4 GHz are used for electromagnetic waves. Therefore, when dielectric materials such as metal or water are placed on the two-dimensional communication sheet 100, electromagnetic wave absorption occurs on the surface of the two-dimensional communication sheet 100. The propagation characteristics of electromagnetic waves passing through the internal dielectric layer change depending on the electrical properties of the material placed on the two-dimensional communication sheet 100, such as the dielectric constant and electrostatic loss tangent. Furthermore, since the relative permittivity of soil itself is small, the relative permittivity of the entire soil is determined by the amount of water contained in the soil. Therefore, the soil moisture content measuring device of this embodiment utilizes these characteristics of two-dimensional communication to measure the amount of moisture in the soil.

[0020] In this embodiment, we will describe the case where the water content of the soil is measured as the amount of water in the soil. Here, the water content of the soil refers to the ratio of the mass of water contained in the soil to the total mass of the soil. It is also possible to use the water content ratio of the soil as a value indicating the amount of water in the soil.

[0021] Next, Figure 3 shows the external appearance of the soil moisture content detection sensor 10 used in the soil moisture content measuring device of this embodiment. Figure 4 shows a cross-sectional view of the soil moisture content detection sensor 10 shown in Figure 3.

[0022] The soil moisture content detection sensor 10 of this embodiment is a soil moisture content detection sensor for detecting the amount of moisture in the soil, and as shown in Figure 3, it is formed in a U-shape or concave shape and has regions 11 and 12 to which a transmitting antenna or a receiving antenna is attached, and a sensing region 13 which is a region for measuring the amount of moisture when inserted into the soil.

[0023] As shown in Figure 4, the soil moisture content detection sensor 10 of this embodiment is constructed by laminating a protective layer 21, a conductive mesh layer 22, a dielectric layer 23 through which radio waves propagate, a shielding layer 24, and a protective layer 25.

[0024] The shield layer 24 is provided on one side of the dielectric layer 23 and is made of a conductive material such as aluminum. The conductive mesh layer 22 is provided on the other side of the dielectric layer 23, and only the areas 11 and 12 where the transmitting antenna and receiving antenna are mounted, and the sensing area 13 are made of a mesh made of conductive material, while the other areas have the same shielding structure as the shield layer 24.

[0025] Furthermore, the protective layers 21 and 25 are configured to cover the shield layer 24 and the conductor mesh layer 22, respectively.

[0026] Thus, unlike the two-dimensional communication sheet 100 for office use described above, the soil moisture content detection sensor 10 in this embodiment has a mesh area of ​​the conductive mesh layer 22 that does not exist over the entire surface of the sheet, but only in the areas 11, 12 where the transmitting antenna or receiving antenna is attached and the sensing area 13, with the remaining areas being conductive areas of the same material as the shielding layer 24.

[0027] Furthermore, a typical two-dimensional communication sheet 100, as shown in Figures 1 and 2, is not intended for use in a state exposed to moisture, and therefore its sides have an exposed dielectric layer 103. Consequently, if a typical two-dimensional communication sheet 100 is buried in the soil as is, it will be affected by moisture in the soil adhering to its sides. In contrast, the soil moisture content detection sensor 10 of this embodiment, as shown in Figure 5, has a dielectric layer 23 with a slightly smaller area than the protective layers 21 and 25, the shielding layer 24, and the conductive mesh layer 22, creating a pouch structure similar to that of a retort food package. Therefore, unlike a typical two-dimensional communication sheet 100, the soil moisture content detection sensor 10 of this embodiment has a structure in which the dielectric layer 23 is not exposed on the sides of the sheet.

[0028] Next, the configuration of the soil moisture content measuring device using the soil moisture content detection sensor 10 described above will be explained with reference to Figure 6.

[0029] As shown in Figure 6, the soil moisture content measuring device of this embodiment consists of a soil moisture content detection sensor 10 shown in Figures 3 and 4, a transmitting antenna 41, a receiving antenna 42, and a moisture content determination device 50.

[0030] The transmitting antenna 41 and the receiving antenna 42 are attached to either region 11 or 12 of the soil moisture content detection sensor 10, respectively. Figure 6 shows the case where the transmitting antenna 41 is attached to region 11 and the receiving antenna 42 is attached to region 12.

[0031] The soil moisture content sensor 10 is then buried in the soil so that the sensing area 13 reaches the depth to which the moisture content is to be measured. However, the areas 11 and 12 on which the transmitting antenna 41 and receiving antenna 42 are attached are adjusted to be above the ground surface.

[0032] The moisture content determination device 50 is connected to the transmitting antenna 41 and the receiving antenna 42. It outputs an electrical signal to the transmitting antenna 41 to transmit electromagnetic waves for two-dimensional communication and receives the received signal at the receiving antenna 42. Based on the state of the received signal received by the receiving antenna 42, the moisture content determination device 50 determines the moisture content of the soil adjacent to the mesh-like sensing area 13 of the conductive mesh layer 22 as the moisture content of the soil.

[0033] Specifically, the moisture content determination device 50 uses the correspondence between the previously measured received signal strength (RSSI: Received Signal Strength Indication) and the soil moisture content to determine the soil moisture content of the soil adjacent to the mesh-like sensing area 13 of the conductive mesh layer 22 from the received signal strength in the received signal.

[0034] Alternatively, the moisture content determination device 50 may use a learning model generated by machine learning using pre-measured soil moisture content and channel state information (CSI) as training data to determine the moisture content of soil adjacent to the sensing area 13 of the conductive mesh layer 22 as the moisture content in the soil from the channel state information in the received signal. Details of measuring the moisture content in the soil based on channel state information (CSI) using machine learning will be described later.

[0035] Next, Figure 7 shows the functional block configuration of the moisture content determination device 50 when determining the soil moisture content using the RSSI of the received signal received by the receiving antenna 42.

[0036] As shown in Figure 7, the moisture content determination device 50 comprises a transmission circuit 51, a reception circuit 52, a signal processing unit 60, a display panel 53, and a data storage unit 54. The signal processing unit 60 is composed of a circuit control unit 61, a signal intensity detection unit 62, a soil moisture content calculation unit 63, and a display control unit 64.

[0037] The transmitting circuit 51 is controlled by the circuit control unit 61 and transmits a high-frequency signal to the transmitting antenna 41. The receiving circuit 52 converts the electromagnetic waves received by the receiving antenna 42 into a received signal and transmits it to the circuit control unit 61.

[0038] The circuit control unit 61 controls the operation of the signal processing unit 60, as well as the operation of the transmitting circuit 51 and the receiving circuit 52. The circuit control unit 61 controls the transmitting circuit 51 and the receiving circuit 52 at specific intervals to perform periodic measurements and transmit and receive electromagnetic waves.

[0039] The signal processing unit 60 is composed of a computer having a memory unit and the like, and processes output signals and signals from each part, including the transmission circuit 51 and the receiving circuit 52.

[0040] The signal strength detection unit 62 acquires RSSI information of the received signal received by the receiving antenna 42 from the circuit control unit 61.

[0041] The soil moisture content calculation unit 63 calculates the soil moisture content from the RSSI information acquired by the signal intensity detection unit 62. There is a linear relationship between soil moisture content and RSSI as shown in Figure 8, and the soil moisture content calculation unit 63 calculates the amount of moisture in the soil by referring to a correspondence table generated based on this relationship. For example, the data storage unit 54 stores data showing the correspondence between soil moisture content and RSSI values, as shown in Figure 8. Then, the soil moisture content calculation unit 63 uses this data, as shown in Figure 8, to calculate the soil moisture content from the RSSI value acquired by the signal intensity detection unit 62.

[0042] The soil moisture content calculation unit 63 then stores the calculated soil moisture content data in the data storage unit 54 and displays it on the display panel 53 via the display control unit 64. In addition to displaying it on the display panel 53, the calculated soil moisture content data may also be transmitted externally using wireless communication equipment or the like. Furthermore, the moisture content determination device 50 may be provided with detection mechanisms for measuring soil information, such as a temperature detection unit like a thermistor capable of measuring the temperature in the ground or on the ground surface, and a pH detection unit capable of detecting the pH in the soil.

[0043] Through this control, the moisture content of the soil near the sensing area 13 of the soil moisture detection sensor 10 buried in the soil is measured, stored in the data storage unit 54, and displayed on the display panel 53.

[0044] In this embodiment, as shown in Figure 6, when the soil moisture content detection sensor 10 is buried in the soil, only the sensing region 13 is mesh-like among the areas that come into contact with the soil. Therefore, the soil in contact with areas other than the sensing region 13 does not affect the propagation characteristics of electromagnetic waves traveling within the dielectric layer 23 inside the sheet.

[0045] Therefore, according to this embodiment, the amount of soil moisture at the desired soil depth, i.e., the location of the sensing area 13, can be accurately measured. Furthermore, the shape of the soil moisture detection sensor 10 is U-shaped or concave, as shown in Figure 3. By making the soil moisture detection sensor 10 U-shaped or concave, the structure is designed to interfere as little as possible with the growth of plant roots in the soil and leaves near the surface. Also, as shown in Figure 6, the areas 11 and 12 of the conductive mesh layer 22, which are the mounting surfaces for the transmitting antenna 41 and the receiving antenna 42, are above ground. Therefore, unlike conventional soil moisture sensors that require the transmitting antenna and receiving antenna to be buried underground, in this embodiment, it is not necessary to bury the transmitting antenna 41 and the receiving antenna 42 underground, and the transmitting antenna 41 and the receiving antenna 42 do not necessarily need to have a costly, completely waterproof structure.

[0046] Next, Figure 9 shows a modified soil moisture content detection sensor 10A, which is a modified version of the soil moisture content detection sensor 10 in this embodiment.

[0047] The soil moisture content detection sensor 10A shown in Figure 9 has a strip-like structure, which is the soil moisture content detection sensor 10 shown in Figure 3 folded in half. Specifically, the soil moisture content detection sensor 10A has a structure in which a transmitting antenna 41 and a receiving antenna 42 are mounted facing each other in regions 11 and 12, respectively, with a two-dimensional communication sheet sandwiched in between. In this structure of the soil moisture content detection sensor 10A, since both the transmitting antenna 41 and the receiving antenna 42 are mounted in close proximity, the circuit and control sections of the transmitting antenna 41 and the receiving antenna 42, as well as the power supply section that supplies power to them, can be mounted on a common board, enabling the configuration of an integrated unit. Therefore, the soil moisture content detection sensor 10A shown in Figure 9 can achieve reduced wiring, space savings, and lower costs compared to the soil moisture content detection sensor 10 shown in Figure 3.

[0048] The above explanation described the case where the amount of moisture in the soil is measured using one soil moisture detection sensor 10. However, multiple soil moisture detection sensors 10 may be buried in the field, and a signal processing mechanism may be configured to perform synchronized measurements and collect the measured values ​​using wireless signals or the like.

[0049] Furthermore, in the embodiment described above, a configuration was described in which a pair of transmitting antennas 41 and receiving antennas 42 are attached to one sensing area 13 on the soil moisture content detection sensor 10. However, the present invention is not limited to such a configuration, and there may be a configuration in which multiple sensing areas 13 are provided, or a configuration in which multiple transmitting antennas 41 and receiving antennas 42 are attached.

[0050] For example, the soil moisture content detection sensor 10B shown in Figure 10 may have a configuration similar to that of the soil moisture content detection sensor 10B shown in Figure 10. In the soil moisture content detection sensor 10B shown in Figure 10, there are two sensing areas 13A and 13B, with one area 11 where the transmitting antenna 41 is mounted and two areas 12A and 12B where the receiving antennas 42A and 42B are mounted. For the sake of simplicity, in the soil moisture content detection sensor 10B shown in Figure 10, the sheet length from the transmitting antenna 41 to each receiving antenna 42A and 42B, and the area of ​​the sensing areas 13A and 13B are the same. If the irrigation amount (soil moisture content) in the two sensing areas 13A and 13B is about the same, the difference in RSSI at the receiving antennas 42A and 42B will be almost zero. If there is a difference in the irrigation amount, the difference in RSSI will be large. By using a soil moisture content detection sensor 10B with such a configuration, it is possible to monitor the irrigation conditions over a wide area with a small number of installations.

[0051] By providing multiple receiving antennas 42A and 42B to a single transmitting antenna 41, it becomes possible to individually determine the amount of soil moisture in the vicinity of multiple sensing areas 13A and 13B. In particular, such determination is possible by using CSI data and a machine learning model, as described below, to determine the amount of soil moisture. For example, if the amount of soil moisture is to be determined in three levels—low, normal, and high—it is sufficient to generate a learning model by performing a minimum of nine combination tests for determination using two sensing areas 13A and 13B.

[0052] Next, we will explain how to measure soil moisture content based on channel status information (CSI) using machine learning.

[0053] In recent years, wireless LAN (Local Area Network) access points and wireless devices (such as personal computers and smartphones) have been placed indoors, and the radio wave conditions and fluctuations between them are acquired as channel status information data (hereinafter abbreviated as CSI data). By analyzing the acquired CSI data, it has become possible to detect human positioning, behavior recognition, and personal identification.

[0054] This CSI (Critical Score Index) is information that indicates changes in amplitude and phase due to the effects of propagation loss, reflection, diffraction, etc., in wireless LAN radio waves. Specifically, this CSI is information on the amplitude and phase of each subcarrier. When the moisture content of the soil near the sensing area 13 of the soil moisture content detection sensor 10 buried in the soil changes, this CSI also changes. Therefore, the moisture content determination device 50 in this embodiment estimates the moisture content in the soil by combining this CSI data with machine learning.

[0055] The process for measuring soil moisture content based on CSI data using machine learning will be explained with reference to the flowchart in Figure 11.

[0056] First, a learning model is generated by performing machine learning using pre-measured soil moisture content and CSI data as training data. The generated learning model takes CSI data from the received signal received by the receiving antenna 42 as input, and outputs the moisture content corresponding to that CSI data. The learning model is then stored in the data storage unit 54 of the moisture content determination device 50. This learning model can be constructed, for example, using a classifier-type neural network model having multiple hidden layers equal to the number of input layers.

[0057] When measuring the amount of moisture in the soil, the moisture content determination device 50 acquires CSI data from the received signal (step S101). Next, the moisture content determination device 50 reads the stored learning model from the data storage unit 54 (step S102). Then, the moisture content determination device 50 inputs the acquired CSI data into the read learning model and acquires the soil moisture content data output from the learning model (step S103). Finally, the moisture content determination device 50 notifies the user of the acquired soil moisture content as a measurement result by displaying it on the display panel 53 or the like (step S104).

[0058] In this way, we will compare the estimated soil moisture content (water content) based on CSI data using machine learning with the actual true value and explain the evaluation results.

[0059] In this evaluation, the CSI (Chemical Saturation Index) was measured using the soil moisture content measuring device of this embodiment for soil samples of black soil with moisture content in 2.5% increments: 0%, 2.5%, 5.0%, 7.5%, 10.0%, 12.5%, 15.0%, 17.5%, and 20.0%. Using the learned model generated from these samples, the CSI of untrained soil samples was evaluated. As a result, the soil moisture content could be estimated with a high accuracy of 99.59%.

[0060] As shown in Figure 12, a wireless communication device 71 may be connected to the moisture content determination device 50, and the system configuration may be such that CSI data is transmitted to a server device 74 on a cloud service via the Internet 73 through a mobile phone communication network 72. The server device 74 on the cloud service stores data for a learning model that estimates soil moisture content as described above, and the estimation of soil moisture content may be performed on this server device 74, and the estimated soil moisture content information may be notified to the user via a personal computer 75 or smartphone. [Explanation of symbols]

[0061] 10, 10A, 10B Soil Moisture Content Detection Sensor 11, 12, 12A, 12B area 13, 13A, 13B Sensing areas 21 Protective layer 22 Conductor mesh layer 23 Dielectric layer 24 Shield layer 25 Protective layer 41 Transmitting antenna 42, 42A, 42B receiving antennas 50 Moisture content determination device 51 Transmitter Circuit 52 Receiving Circuit 53 Display Panel 54 Data Storage Unit 60 Signal Processing Unit 61 Circuit Control Unit 62 Signal strength detection unit 63. Soil moisture content calculation unit 64 Display Control Unit 71 Wireless communication devices 72. Mobile phone network 73 Internet 74 Server equipment (cloud service) 75 Personal computer

Claims

1. A soil moisture content sensor for detecting the amount of moisture in the soil, A dielectric layer through which radio waves propagate, A shielding layer made of a conductive material is provided on one side of the dielectric layer, A mesh layer is provided on the other side of the dielectric layer, in which the area where the transmitting antenna and receiving antenna are attached and the sensing area for measuring the amount of moisture when inserted into the soil are made of a mesh made of a conductive material, and the other areas have the same shielding structure as the shield layer, A protective layer configured to cover the shield layer and the mesh layer, A soil moisture content detection sensor equipped with the following features.

2. Transmitting antenna and Receiving antenna and A soil moisture content detection sensor comprising: a dielectric layer through which radio waves propagate; a shielding layer provided on one side of the dielectric layer and made of a conductive material; a mesh layer provided on the other side of the dielectric layer, having a mesh-like structure made of a conductive material in the area where a transmitting antenna and a receiving antenna are mounted and in the area for measuring moisture content when inserted into soil, and the other area having the same shielding structure as the shielding layer; and a protective layer configured to cover the shielding layer and the mesh layer. A determination unit that determines the amount of moisture in the soil adjacent to the sensing area of ​​the mesh layer based on the state of the received signal received by the receiving antenna, A soil moisture content measuring device equipped with [unspecified features].

3. The soil moisture content measuring device according to claim 2, wherein the determination unit determines the moisture content of the soil adjacent to the sensing area of ​​the mesh layer as the amount of moisture in the soil, based on the received signal intensity in the received signal, using the correspondence between the received signal intensity and the soil moisture content, which has been measured in advance.

4. The soil moisture content measuring device according to claim 2, wherein the determination unit uses a learning model generated by performing machine learning on pre-measured soil moisture content and channel state information as training data to determine the moisture content of soil adjacent to the sensing area of ​​the mesh layer as the amount of moisture in the soil from the channel state information in the received signal.

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