Liquid surface level detection sensor and liquid surface level measurement device

Abstract

To measure the liquid surface level of a liquid in a container with high accuracy from outside the container.SOLUTION: A liquid surface level detection sensor 10 is a liquid surface level detection sensor for detecting the liquid surface level of a liquid in a container 70, and has a laminated structure of a dielectric layer 23 through which radio waves propagate, a wiring mesh layer 22, and a shield layer 24. The wiring mesh layer 22 is provided on any surface of the dielectric layer 23, and an area where a transmitting antenna 41 and a receiving antenna 42 are mounted and a sensing area arranged close to the container 70 whose liquid surface level is to be detected are formed at least in a mesh shape made of a conductive material. The shield layer 24 is provided in an area of the dielectric layer 23 where the wiring mesh layer 22 is not provided, and is made of a conductive material such as aluminum.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a liquid level detection sensor and a liquid level measurement device. [Background technology]

[0002] Generally, when detecting the liquid level of a liquid contained in a container, a liquid level detection sensor using a float is provided in the container to detect the liquid level. However, when the liquid in the container is food, problems such as hygiene problems may arise, or the liquid level detection sensor provided in the container may be corroded by the liquid in the container.

[0003] Therefore, there is a demand for a technology that can detect the liquid level in a container from outside the container.For example, Patent Document 1 discloses a method for detecting the presence of water or the like in a non-contact manner based on a change in the received intensity of electromagnetic waves of a frequency that is easily absorbed by the substance to be detected, such as water. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-135928 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the conventional technology disclosed in the above-mentioned Patent Document 1 can detect the presence or absence of a substance such as water from the outside of a container, but cannot detect the liquid level of the liquid such as water. Furthermore, since such conventional technology uses changes in the received strength of electromagnetic waves, there is a problem that it may be affected by the positions of the transmitting antenna and receiving antenna and the presence of metal objects in the vicinity.

[0006] An object of the present invention is to provide a liquid level detection sensor and a liquid level measurement device that are capable of measuring the liquid level of a liquid in a container from outside the container with high accuracy. [Means for solving the problem]

[0007] In order to achieve the above object, a liquid level detection sensor according to a first aspect of the present invention is a liquid level detection sensor for detecting a liquid level of a liquid in a container, comprising: A dielectric layer through which radio waves propagate; a mesh layer provided on any one surface of the dielectric layer, the mesh layer having an area where a wireless transmitting antenna and a wireless receiving antenna are mounted and a sensing area disposed adjacent to a container whose liquid level is to be detected, the area being made of at least a conductive material and having a mesh shape; a shield layer made of a conductive material and provided in an area of ​​the dielectric layer where the mesh layer is not provided.

[0008] In addition, the liquid level measuring device according to the second aspect of the present invention is A radio transmitting antenna; A radio receiving antenna; a liquid level detection sensor comprising: a dielectric layer through which radio waves propagate; a mesh layer provided on either side of said dielectric layer, said mesh layer having at least a region where a wireless transmitting antenna and a wireless receiving antenna are attached and a sensing region disposed adjacent to a container for which the liquid level is to be detected, said mesh layer being made of a conductive material; and a shield layer provided on an area of ​​said dielectric layer where said mesh layer is not provided and made of a conductive material; and a determination unit that determines the liquid level of the liquid in a container to which the mesh region of the mesh layer is placed in close contact, based on the state of the reception signal received by the wireless receiving antenna.

[0009] In addition, in the liquid level measuring device of the third aspect of the present invention, the determination unit determines the liquid level in a container to which the sensing area of ​​the mesh layer is placed in close proximity from the received signal strength in the received signal, using a correspondence relationship between the received signal strength measured in advance and the liquid level of the liquid in the container.

[0010] In addition, in the liquid level measuring device of the fourth aspect of the present invention, the determination unit determines the liquid level in a container to which the sensing area of ​​the mesh layer is placed in close proximity from the channel state information in the received signal using a learning model generated by performing machine learning using a previously measured liquid level in the container and channel state information as learning data. Effect of the Invention

[0011] According to the present invention, it is possible to provide a liquid level detection sensor and a liquid level measurement device that are capable of measuring the liquid level of a liquid in a container from outside the container with high accuracy. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view of a typical two-dimensional communication sheet 100. [Diagram 2] 2 is a cross-sectional view of the two-dimensional communication sheet 100 shown in FIG. [Diagram 3] FIG. 1 is a diagram for explaining the configuration of a liquid level measurement device according to a first embodiment of the present invention. [Figure 4] 4 is an enlarged view of the liquid level detection sensor 10 shown in FIG. [Diagram 5] FIG. 1 is an external view of a liquid level detection sensor 10 according to a first embodiment of the present invention, as viewed from a wiring mesh layer 22 side. [Figure 6] 2 is a diagram showing a functional block configuration of a liquid level determination device 50. FIG. [Figure 7] FIG. 13 is a diagram showing an example of data showing the relationship between the liquid level and RSSI. [Figure 8] FIG. 4 is a diagram showing a liquid level detection sensor 10A according to a second embodiment of the present invention. [Figure 9] FIG. 11 is an external view of a liquid level detection sensor 10A according to a second embodiment of the present invention, as viewed from the wiring mesh layer 22A side. [Figure 10] FIG. 11 is a diagram showing a liquid level detection sensor 10B according to a third embodiment of the present invention. [Figure 11] FIG. 11 is an external view of a liquid level detection sensor 10B according to a third embodiment of the present invention, as viewed from the sensing region side of a wiring mesh layer 22D. [Figure 12] FIG. 13 is a diagram showing a liquid level detection sensor 10C according to a fourth embodiment of the present invention. [Figure 13] FIG. 11 is an external view of a liquid level detection sensor 10C according to a fourth embodiment of the present invention, as viewed from the sensing region side of a wiring mesh layer 22D. [Figure 14] 13 is a diagram showing an example of use of a liquid level detection sensor 10C according to a fourth embodiment of the present invention. FIG. [Figure 15] 11 is a flowchart for explaining the flow of a liquid level measurement process based on CSI data using machine learning. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Next, an embodiment of the present invention will be described in detail with reference to the drawings.

[0014] The liquid level measurement device of this embodiment uses a two-dimensional communication technology that uses a planar communication medium called a two-dimensional communication sheet. Therefore, before describing the liquid level measurement device of this embodiment, this two-dimensional communication technology will be described.

[0015] FIG. 1 shows a perspective view of a typical two-dimensional communication sheet 100, and FIG.

[0016] As shown in FIG. 2, the two-dimensional communication sheet 100 has a structure in which, from the front side, the surface that inputs and outputs electromagnetic waves is the front, a protective layer 101, a conductor mesh layer 102 that forms a mesh-like conductor wiring, a dielectric layer 103, a shielding layer 104 whose entire surface is a conductor, and a protective layer 105 on the back side are laminated in that order.

[0017] Resin materials, rubber materials, etc. are used as materials for the dielectric layer 103, and materials with lower dielectric constants and electrostatic dissipation factor (tan δ) are more suitable as materials because they have better transmission characteristics. Materials used for wiring materials such as aluminum, copper, and silver are suitable for the materials used for the conductor mesh layer 102 and the shield layer 104. In this case, the lattice shape of the conductor mesh layer 102 has an optimal wiring pattern (line width, line pitch) depending on the sheet characteristics including thickness and size, the characteristics of the dielectric material used for the dielectric layer 103, etc. For this reason, the wiring pattern of the conductor mesh layer 102 is designed to have an optimal line width and line pitch.

[0018] Next, the principle of two-dimensional communication using this two-dimensional communication sheet 100 will be described.

[0019] When two-dimensional communication is performed, 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 travel inside the dielectric layer 103 by electromagnetic coupling. In the process, a small amount of electromagnetic waves leaks onto the surface of the two-dimensional communication sheet 100. The leaked electromagnetic waves are a type of electromagnetic waves called evanescent waves. When a receiving antenna 120 is placed close to an arbitrary point on the surface of the two-dimensional communication sheet 100, communication is established by electromagnetic coupling. The two-dimensional communication performed in this manner has the advantage that the electromagnetic wave intensity rapidly attenuates when it is several centimeters away from the surface of the two-dimensional communication sheet 100, so that the problem of information leakage is unlikely to occur and radio wave interference from space is unlikely to occur. Therefore, 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 an office.

[0020] Here, the frequency of the electromagnetic waves used in the two-dimensional communication is high, for example, 2.4 GHz. Therefore, when a dielectric material such as metal or water is placed on the two-dimensional communication sheet 100, the electromagnetic waves are absorbed on the surface of the two-dimensional communication sheet 100, and the propagation characteristics of the electromagnetic waves passing through the internal dielectric layer change depending on the electrical characteristics such as the dielectric constant and electrostatic tangent of the material placed on the two-dimensional communication sheet 100. Therefore, in this embodiment, the liquid level of a liquid such as water contained in a container is measured using such a two-dimensional communication technology. Here, the dielectric constant of a liquid such as water is large and the dielectric constant of air is small compared to the dielectric constant of the liquid, so the more the amount of liquid contained in the container, the greater the change in the propagation characteristics in the two-dimensional communication. And the amount of liquid close to the two-dimensional communication sheet changes depending on the liquid level. Therefore, in the liquid level measurement device of this embodiment, the liquid level of the liquid contained in the container is measured by utilizing such characteristics of two-dimensional communication.

[0021] In this embodiment, the liquid level is measured as the liquid surface position of the liquid contained in a container. Here, the liquid surface position means the position of the interface between the liquid and the gas in the container (water level). If the cross-sectional area of ​​the container is approximately the same at any height in the container, the liquid surface position means the remaining amount of liquid in the container, and is a value indicating the percentage of the remaining amount when a full tank is 100%.

[0022] [First embodiment] Next, the configuration of the liquid level measuring device according to the first embodiment of the present invention will be described with reference to FIG.

[0023] As shown in Fig. 3, the liquid level measurement device of this embodiment is composed of a liquid level detection sensor 10 that uses two-dimensional communication technology, a transmitting antenna 41, a receiving antenna 42, and a liquid level determination device 50. An enlarged view of the liquid level detection sensor 10 shown in Fig. 3 is shown in Fig. 4.

[0024] In this embodiment, a case where the remaining amount of a beverage such as water, coffee, juice, etc. in a container 70 in a drink server will be described as an example.

[0025] The liquid level detection sensor 10 of this embodiment is a liquid level detection sensor for detecting the liquid level of a liquid in a container 70, and has a laminated structure of a dielectric layer 23 through which radio waves propagate, a wiring mesh layer 22, and a shielding layer 24.

[0026] The wiring mesh layer 22 is provided on either surface of the dielectric layer 23, and the area where the transmitting antenna 41 and the receiving antenna 42 are mounted and the sensing area located adjacent to the container 70 in which the liquid level is to be detected are at least mesh-like made of a conductive material.

[0027] The shield layer 24 is provided in an area of ​​the dielectric layer 23 where the wiring mesh layer 22 is not provided, and is made of a conductive material such as aluminum.

[0028] The transmitting antenna 41 and the receiving antenna 42 are each attached to one of the end regions of the wiring mesh layer 22. In Fig. 4, the transmitting antenna 41 is attached to an upper region of the region where the wiring mesh layer 22 contacts the container 70, and the receiving antenna 42 is attached to a lower region of the region where the wiring mesh layer 22 contacts the container 70.

[0029] The material of the dielectric layer 23 is preferably a relatively flexible resin or rubber material that has a low dielectric constant and dielectric loss and can be easily fitted to the shape of the container 70. The container 70 is also preferably flat and free of irregularities.

[0030] The transmitting antenna 41 and the receiving antenna 42, which are patch antennas, are fixed so as to be in close contact with the wiring mesh layer 22, and shielding films 25, 26 made of, for example, aluminum tape are provided on the side opposite to the side in close contact with the wiring mesh layer 22. The shielding films 25, 26 are provided to eliminate the effects of radio wave leakage and disturbances (such as radio waves entering directly from a transmitter through space).

[0031] The measurement target in this embodiment is the liquid level in a non-metallic container 70 such as a plastic tank, and is assumed to be of a weight and size that can be carried by hand. Therefore, the liquid level detection sensor 10 of this embodiment is smaller than a general two-dimensional communication sheet, and since the distance between the transmitting antenna 41 and the receiving antenna 42 is short, it is necessary to provide shielding films 25 and 26 to suppress the influence of disturbances. In addition, the transmitting antenna 41 and the receiving antenna 42 may be made of a general glass epoxy base material or a flexible base material.

[0032] 5 shows an external view of the liquid level detection sensor 10 in this embodiment as viewed from the wiring mesh layer 22 side. Referring to Fig. 5, it can be seen that the areas of the wiring mesh layer 22 where the transmitting antenna 41 and the receiving antenna 42 are provided are covered with the shielding films 25 and 26, respectively, and only the sensing area in contact with the container 70 is exposed.

[0033] This embodiment can be used in various fields that detect liquid levels such as water levels, for example, in residential / commercial facilities as a remaining gauge for water / drink servers and for detecting when to refill, and in medical settings as a progress management and end detection for infusions. In addition, the liquid level measuring device of this embodiment is not limited to cases where the liquid to be measured contains water because it detects differences in dielectric constant, and can also be used in fields such as remaining gauges for fuels such as gasoline and ethanol in plastic fuel tanks.

[0034] 3, the liquid level determination device 50 is connected to a transmitting antenna 41 and a receiving antenna 42, outputs an electrical signal for transmitting electromagnetic waves for two-dimensional communication to the transmitting antenna 41, and inputs a received signal received by the receiving antenna 42. The liquid level determination device 50 determines the liquid level of the liquid in the container 70 that is placed in close contact with or close to the mesh-like sensing region of the conductor mesh layer 22, based on the state of the received signal received by the receiving antenna 42.

[0035] Specifically, the liquid level determination device 50 determines the liquid level of the liquid in the container 70, which is placed in close contact with or adjacent to the mesh-shaped sensing region of the conductor mesh layer 22, from the received signal strength of the received signal, using a correspondence between a previously measured received signal strength (RSSI: Received Signal Strength Indication) and the liquid level of the liquid in the container 70.

[0036] Alternatively, the liquid level determination device 50 may use a learning model generated by performing machine learning using a previously measured liquid level in the container and channel state information (CSI) as learning data, to determine the liquid level of the liquid in the container 70 that is placed in close contact with or close to the mesh-like sensing region of the conductor mesh layer 22, from the channel state information in the received signal. Details of the measurement of the liquid level based on the channel state information (CSI) using machine learning will be described later.

[0037] Next, a functional block configuration of the liquid level determination device 50 in the case where the liquid level is determined using the RSSI of the signal received by the receiving antenna 42 is shown in FIG.

[0038] 6, the liquid level determination device 50 includes 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 also composed of a circuit control unit 61, a signal intensity detection unit 62, a liquid level calculation unit 63, and a display control unit 64.

[0039] The transmission circuit 51 is controlled by the circuit control unit 61 and transmits a high-frequency signal to the transmission antenna 41. The reception circuit 52 converts the electromagnetic waves received by the reception antenna 42 into a reception signal and transmits it to the circuit control unit 61.

[0040] The circuit control unit 61 controls the operation of the signal processing unit 60, and also controls the operation of the transmission circuit 51 and the reception circuit 52. In order to perform periodic measurements, the circuit control unit 61 controls the transmission circuit 51 and the reception circuit 52 at specific intervals to transmit and receive electromagnetic waves.

[0041] The signal processing unit 60 is configured by a computer having a storage unit and the like, and processes output signals to each unit including the transmitting circuit 51 and the receiving circuit 52 and signals from each unit.

[0042] The signal strength detection unit 62 acquires from the circuit control unit 61 information on the RSSI of the signal received by the receiving antenna 42 .

[0043] The liquid level calculation unit 63 calculates the liquid level from the information of the RSSI acquired by the signal strength detection unit 62. An example of the relationship between the liquid level and the RSSI is shown in the graph of FIG. 7. The horizontal axis of the graph shown in FIG. 7 is the liquid level in the container 70, with 0% indicating an empty water state and 100% indicating a full water state. The liquid level and the RSSI have a linear relationship as shown in FIG. 7, and the liquid level calculation unit 63 calculates the liquid level of the liquid in the container 70 by referring to a correspondence table generated based on such a relationship. For example, the data storage unit 54 stores data showing the correspondence relationship between the liquid level and the RSSI value as shown in FIG. 7. Then, the liquid level calculation unit 63 calculates the liquid level from the RSSI value acquired by the signal strength detection unit 62 using the data as shown in FIG. 7.

[0044] The liquid level calculation unit 63 then stores the calculated liquid level data in the data storage unit 54, and also displays it on the display panel 53 via the display control unit 64. Therefore, according to this embodiment, it is possible to hygienically display the liquid level of the liquid such as a beverage in the container 70, that is, the remaining amount, without providing a float sensor or the like in the container 70. Then, when the remaining amount becomes low, it is possible to prevent the occurrence of a situation in which the beverage in the container 70 runs out by taking measures such as adding more beverage.

[0045] [Second embodiment] Next, a liquid level detection sensor 10A according to a second embodiment of the present invention will be described with reference to FIG.

[0046] In the liquid level detection sensor 10A of this embodiment, a shield layer 24B, a wiring mesh layer 22A, and a shield layer 24C are provided on the side where the dielectric layer 23 contacts the container 70. In addition, in the liquid level detection sensor 10A, a wiring mesh layer 22B, a shield layer 24A, and a wiring mesh layer 22C are provided on the side opposite to the side where the dielectric layer 23 contacts the container 70.

[0047] The container 70 is disposed in close or proximity to the wiring mesh layer 22 A. The transmitting antenna 41 is disposed on the wiring mesh layer 22 B, and the receiving antenna 42 is disposed on the wiring mesh layer 22 C.

[0048] FIG. 9 shows an external view of the liquid level detection sensor 10A according to the present embodiment shown in FIG. 8, as viewed from the wiring mesh layer 22A side.

[0049] In the liquid level detection sensor 10A in this embodiment, unlike the liquid level detection sensor 10 in the first embodiment, the surface on which the transmitting antenna 41 and the receiving antenna 42 are installed and the surface on which the sensing area for detecting the liquid level in the container 70 is provided are not flush with each other. Therefore, according to the liquid level detection sensor 10A in this embodiment, it is possible to prevent interference between the coaxial connectors on the substrates of the transmitting antenna 41 and the receiving antenna 42 and the container 70.

[0050] [Third embodiment] Next, a liquid level detection sensor 10B according to a third embodiment of the present invention will be described with reference to FIG.

[0051] In the second embodiment described above, it was necessary to use a special sheet in which a wiring mesh layer and a shielding layer were mixed. In contrast, in the liquid level detection sensor 10B of this embodiment, interference between the coaxial connectors on the substrates of the transmitting antenna 41 and the receiving antenna 42 and the container 70 is avoided without using such a special sheet.

[0052] The liquid level detection sensor 10B of this embodiment has a configuration in which a shield layer 24D, a dielectric layer 23A, and a wiring mesh layer 22D are wound around a central holding plate 30. A shield film 25A is provided so as to cover the transmitting antenna 41 and a partial area of ​​the wiring mesh layer 22D. A shield film 26A is provided so as to cover the receiving antenna 42 and a partial area of ​​the wiring mesh layer 22D.

[0053] FIG. 11 shows an external view of the liquid level detection sensor 10B according to this embodiment shown in FIG. 10, as viewed from the sensing region side of the wiring mesh layer 22D.

[0054] Even when the liquid level detection sensor 10B having the configuration of this embodiment is used, interference between the coaxial connectors on the substrates of the transmitting antenna 41 and the receiving antenna 42 and the container 70 can be avoided.

[0055] [Fourth embodiment] Next, a liquid level detection sensor 10C according to a fourth embodiment of the present invention will be described with reference to FIG.

[0056] The liquid level detection sensor 10C of this embodiment is configured to have a plurality of sensing regions.

[0057] As shown in FIG. 12, the liquid level detection sensor 10C of this embodiment is configured such that, compared to the liquid level detection sensor 10B of the third embodiment shown in FIG. 13, shielding films 27A, 27B are provided and the shielding films 25A, 26A are replaced with shielding films 25B, 26B.

[0058] FIG. 13 shows an external view of the liquid level detection sensor 10C according to this embodiment shown in FIG. 12, as viewed from the sensing region side of the wiring mesh layer 22D.

[0059] As can be seen by referring to FIG. 13, three sensing regions are configured in the wiring mesh layer 22D.

[0060] An example of use of the liquid level detection sensor 10C of this embodiment is shown in Fig. 14. The liquid level detection sensor 10C of this embodiment is used in a drink server using a plurality of containers 71-73, for example, not to measure the remaining amount in each container, but to determine and display whether the liquid level of the beverage in any container has reached a replacement level that requires replacement. Note that as a method for such determination, a determination method using a learning model generated by machine learning using CSI (Channel State Information) data can be used.

[0061] [CSI-based assessment method] Next, we explain a method for measuring liquid levels based on channel state information (CSI) using machine learning.

[0062] 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 have been obtained as channel state information data (hereinafter referred to as CSI data). The obtained CSI data has then been analyzed to detect people's positions, recognize their behavior, and identify individuals.

[0063] The CSI is information indicating changes in amplitude and phase due to the influence of propagation loss, reflection, diffraction, etc., in radio waves of a wireless LAN. Specifically, the CSI is information on the amplitude and phase for each subcarrier. The CSI also changes as the amount of liquid in the container 70 disposed close to the sensing area of ​​the liquid level detection sensor 10 changes. Therefore, the liquid level determination device 50 in the first to fourth embodiments described above estimates the liquid level by combining the CSI data with machine learning.

[0064] The flow of the liquid level measurement process based on CSI data using machine learning will be described with reference to the flowchart of FIG. 15.

[0065] First, a learning model is generated by performing machine learning using a previously measured liquid level and CSI data as learning data. The generated learning model is configured to input the CSI data of the signal received by the receiving antenna 42 and output a liquid level corresponding to the CSI data. The learning model is then stored in the data storage unit 54 of the liquid level determination device 50. This learning model can be configured, for example, using a classifier-type neural network model having a plurality of hidden layers, the same number as the input layers.

[0066] When measuring the liquid level in the container 70, the liquid level determination device 50 acquires CSI data from the received signal (step S101). Next, the liquid level determination device 50 reads out the stored learning model from the data storage unit 54 (step S102). Then, the liquid level determination device 50 inputs the acquired CSI data into the read learning model and acquires the liquid level data output from the learning model (step S103). Finally, the liquid level determination device 50 notifies the user by displaying the acquired liquid level value as a measurement result on the display panel 53 or the like (step S104). [Explanation of symbols]

[0067] 10, 10A, 10B, 10C Liquid level detection sensor 22, 22A to 22D Wiring mesh layer 23, 23A Dielectric layer 24, 24A~24D Shielding layer 25, 25A, 25B Shielding film 26, 26A, 26B Shielding film 27A, 27B Shielding film 30 Holding plate 41 Transmitting Antenna 42 Receiving antenna 50 Liquid level determination device 51 Transmitting circuit 52 Receiving circuit 53 Display Panel 54 Data storage unit 60 Signal Processing Section 61 Circuit control section 62 Signal strength detector 63 Liquid level calculation section 64 Display control section 70~73 container

Claims

1. A liquid level detection sensor for detecting a liquid level of a liquid in a container, comprising: A dielectric layer through which radio waves propagate; a mesh layer provided on any one surface of the dielectric layer, the mesh layer having an area where a wireless transmitting antenna and a wireless receiving antenna are mounted and a sensing area disposed adjacent to a container whose liquid level is to be detected, the area being made of at least a conductive material and having a mesh shape; a shield layer made of a conductive material and provided in an area of ​​the dielectric layer where the mesh layer is not provided; A liquid level detection sensor comprising:

2. A radio transmitting antenna; A radio receiving antenna; a liquid level detection sensor including a dielectric layer through which radio waves propagate, a mesh layer provided on either side of the dielectric layer, the mesh layer being made of at least a conductive material in an area where a wireless transmitting antenna and a wireless receiving antenna are attached and in a sensing area disposed adjacent to a container whose liquid level is to be detected, and a shield layer made of a conductive material and provided in an area of ​​the dielectric layer where the mesh layer is not provided; a determination unit that determines a liquid level in a container to which the mesh region of the mesh layer is placed in close contact based on a state of a reception signal received by the wireless receiving antenna; A liquid level measuring device comprising:

3. 3. The liquid level measuring device according to claim 2, wherein the determination unit determines the liquid level in a container to which the sensing area of ​​the mesh layer is disposed in close proximity from the received signal strength in the received signal by using a correspondence relationship between a previously measured received signal strength and the liquid level of the liquid in the container.

4. 3. The liquid level measuring device according to claim 2, wherein the determination unit determines the liquid level in a container to which the sensing area of ​​the mesh layer is arranged in close proximity from channel state information in the received signal using a learning model generated by performing machine learning using a previously measured liquid level in the container and channel state information as learning data.

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