Frequency domain sensor for measuring soil surface moisture

Abstract

The utility model discloses a frequency domain sensor for measuring soil surface moisture, which relates to the technical field of near-surface soil moisture measurement and comprises a data analysis device. The sampling assembly is connected with the input end of the data analysis device and comprises a printed circuit board and an insulation unit located on the side face, away from the data analysis device, of the printed circuit board, and a probe unit is arranged on the insulation unit; the probe unit comprises a central signal probe and a plurality of grounding probes arranged along the circumference of the central signal probe. The central signal probe and the grounding probe form a coaxial structure, the transmission stability of signals can be improved on the premise of ensuring the uniformity of a magnetic field, and the cooperation of the printed circuit board and the insulation unit can also reduce noise obstruction, signal interference and cross influence.

Description

TECHNICAL FIELD

[0001] The utility model relates to near surface soil moisture measurement technical field, concretely relates to a frequency domain sensor for measuring soil surface layer moisture. BACKGROUND

[0002] Near surface soil moisture is a highly dynamic environmental state variable, which is of fundamental importance to many climate, hydrology, biology and biogeochemical processes, and plays an important role in soil composition determination, border and coastline monitoring and scientific and technical support in the field of engineering construction. Therefore, accurate quantification and monitoring of its spatio-temporal variation is often crucial.

[0003] In the near surface soil moisture test, the soil dielectric probe is an important way and implementation to guide the electromagnetic wave into the soil sample, and is an important condition to ensure the smooth progress of the test. The probe can collect temperature, humidity and other parameters in the soil in real time, and convert these parameters into electrical signals for transmission. In the existing probe specification, the single-axis probe has uniform electromagnetic field distribution, which can better collect soil data. However, the soil environment is complex and changeable, and the single-axis probe may be affected by soil humidity, temperature and other factors during the measurement process, resulting in errors in the measurement results. Compared with single probe, multiple probes can ensure the accuracy of data collection, but at the same time, signal interference and cross between multiple probes may occur. SUMMARY

[0004] The present application provides a frequency domain sensor for measuring soil surface layer moisture, which can solve the technical problems of single-axis probe being easily affected by soil environment, leading to errors in measurement results, and signal interference and cross between multiple probes.

[0005] The present application provides a frequency domain sensor for measuring soil surface layer moisture, which can solve the technical problems of single-axis probe being easily affected by soil environment, leading to errors in measurement results, and signal interference and cross between multiple probes.

[0006] The data analysis device is connected to the sampling assembly, and the sampling assembly includes a printed circuit board and an insulating unit located on the side of the printed circuit board away from the data analysis device.

[0007] The data analysis device is connected to the sampling assembly, and the sampling assembly includes a printed circuit board and an insulating unit located on the side of the printed circuit board away from the data analysis device.

[0008] In one embodiment, the side of the printed circuit board close to the data analysis device is provided with an analysis device connector.

[0009] In one embodiment, the printed circuit board is provided with a welding hole unit opposite the position of the probe unit for connecting the probe unit.

[0010] In one embodiment, the welding hole unit comprises a center welding hole located at the center of the printed circuit board, and a plurality of peripheral welding holes corresponding to the number of the grounding probes.

[0011] In one embodiment, the insulation unit comprises an insulation positioning base fixedly connected to the printed circuit board.

[0012] In one embodiment, the insulation positioning base is provided with a positioning hole unit penetrating through the insulation positioning base along the axial direction.

[0013] In one embodiment, the positioning hole unit comprises a center positioning hole located at the center of the insulation positioning base, and a plurality of peripheral positioning holes corresponding to the number of the grounding probes.

[0014] In one embodiment, the center signal probe penetrates through the center positioning hole to connect the center welding hole, and each of the grounding probes penetrates through a peripheral positioning hole to connect a peripheral welding hole.

[0015] In one embodiment, the plurality of grounding probes are equidistantly arranged along the circumference of the center signal probe.

[0016] In one embodiment, the length of the center signal probe is smaller than the length of the grounding probes.

[0017] The technical scheme provided by the embodiments of the present application has the following beneficial effects:

[0018] The frequency domain sensor in the present application is provided with a center signal probe to ensure efficient and accurate signal transmission, and the plurality of grounding probes further enhance the stability of signal transmission, reduce signal attenuation and distortion, and cooperate with the printed circuit board to simplify the traditional multiplexer with channel switching function into a printed circuit board, effectively reducing noise interference, and the insulation positioning base can shield the probe unit, effectively isolate the electromagnetic field between the probes and the probe unit and the outside world, prevent signal interference and cross-influence between them, and further ensure measurement accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical scheme in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0020] Figure 1A frequency domain sensor structure diagram for measuring soil surface moisture provided by the embodiment of the present application;

[0021] Figure 2 A printed circuit board side view of the frequency domain sensor for measuring soil surface moisture provided by the embodiment of the present application;

[0022] Figure 3 An insulating positioning base side view of the frequency domain sensor for measuring soil surface moisture provided by the embodiment of the present application.

[0023] In the figure: 1, data analysis device; 2, printed circuit board; 3, center signal probe; 4, ground probe; 5, analysis device connector; 6, center solder hole; 7, outer periphery solder hole; 8, insulating positioning base; 9, center positioning hole; 10, outer periphery positioning hole. DETAILED DESCRIPTION

[0024] In order to make the person skilled in the art better understand the scheme of the present application, the technical scheme in the embodiment of the present application will be described clearly and completely below in combination with the drawings in the embodiment of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor fall within the scope of protection of the present application.

[0025] First, some technical terms in the present application are explained and described in order to facilitate the understanding of the present application by the person skilled in the art:

[0026] SMA: Soil Moisture Analyzer, is a highly integrated device integrating soil moisture content, temperature sensing, acquisition, embedded computing, wireless transmission and power supply functions. It is based on the frequency dielectric reflection (FDR) measurement principle, which measures the soil moisture content by the frequency change of the electromagnetic wave in different dielectric coefficient substances. At the same time, the device also has a built-in high-precision digital temperature sensor for measuring soil temperature.

[0027] The embodiment of the present application provides a frequency domain sensor for measuring soil surface moisture, which can solve the technical problems in the prior art that single-axis probes are easily affected by soil environment, resulting in errors in measurement results, and signal interference and cross between multiple probes.

[0028] The frequency domain sensor in the application comprises a data analysis device 1 and a sampling assembly connected to the input end of the data analysis device 1, the data analysis device 1 comprises an input end and an output end, the input end is used for connecting the sampling assembly to obtain the soil information obtained by the sampling assembly, and the output end is used for connecting a host computer and sending the soil information obtained by the sampling assembly to the host computer for analysis, calculation and storage.

[0029] Specifically, Figure 1 A frequency domain sensor structure schematic diagram for measuring the surface layer moisture of soil is provided for the embodiment of the application, as shown in Figure 1 The sampling assembly comprises a printed circuit board 2 and an insulating unit located on the side of the printed circuit board 2 away from the data analysis device 1, and the insulating unit is provided with a probe unit.

[0030] In a possible implementation, the data analysis device 1 is a vector network analyzer, and data analysis, storage and the like are performed by connecting a host computer.

[0031] In a possible implementation, the printed circuit board 2 is disc-shaped, the printed circuit board 2 comprises a front surface provided with a circuit pattern and a connecting point and a back surface used for wiring, the insulating unit and the probe unit are arranged on the front surface of the printed circuit board 2, the probe unit penetrates through the insulating unit and contacts the front surface of the printed circuit board 2 to form a complete circuit, information transmission is completed through the printed circuit board 2, and the back surface of the printed circuit board 2 faces the data analysis device 1. The printed circuit board 2 is not only used for connecting the probe unit and the data analysis device 1, but also has a small thickness and a small impedance, and can reduce the information transmission path and the noise source to a certain extent. The insulating unit is used for positioning and isolating the probe unit, preventing magnetic field interference between the multiple probes in the probe unit and between the probe unit and the external environment, and affecting the measurement accuracy.

[0032] Further, the probe unit comprises a center signal probe 3 and a plurality of ground probes 4 arranged along the circumference of the center signal probe 3. The plurality of ground probes 4 are arranged around the center signal probe 3 to form a coaxial structure. In this structure, the center signal probe 3 serves as an inner conductor, and the ground probes 4 serve as a ground ring. The center signal probe 3 is responsible for transmitting signals. Since it is located at the center, the signals can be more uniformly distributed around the center signal probe 3 during transmission, reducing signal distortion and attenuation. The plurality of ground probes 4 are arranged around the outer periphery to form an electromagnetic shielding layer. This shielding layer can effectively block external electromagnetic field interference and protect the signals transmitted by the center signal probe 3 from being affected. This coaxial structure helps to reduce signal interference and attenuation during transmission, thereby improving transmission stability.

[0033] In a possible implementation, the six grounding probes 4 form a magnetic field similar to that of a single-axis probe, but with a wider coverage and higher uniformity. Based on this arrangement, the frequency domain sensor in the present application can simultaneously have the magnetic field uniformity of a single-axis probe and the stability and comprehensiveness of a multi-axis magnetic field.

[0034] Meanwhile, in combination with the printed circuit board 2 and the insulating unit, the signal transmission between the respective probes of the probe unit can be ensured to be stable and reliable, and the electromagnetic fields between the respective probes and between the probe unit and the outside world can be effectively isolated, preventing signal interference and cross-influence therebetween, which helps to ensure that each probe can independently and accurately collect data, thereby improving the measurement accuracy and reliability of the entire frequency domain sensor.

[0035] Further, as shown in Figure 1 , the side of the printed circuit board 2 close to the data analysis device 1 is provided with an analysis device connector 5. In a possible implementation, the analysis device connector 5 is an SMA adapter, which is a widely used small-sized threaded coaxial connector and is widely used in the radio frequency and microwave industry. The basic structure includes four parts of contact, insulator, shell and accessories. The SMA adapter is a commonly used technology, and its specific internal structure and mechanism will not be described in detail here.

[0036] Further, the printed circuit board 2 is provided with a welding hole unit opposite the position of the probe unit for connecting the probe unit, Figure 2 A side view of a printed circuit board 2 of a frequency domain sensor for measuring soil surface moisture according to an embodiment of the present application is shown in Figure 2 , which includes a central welding hole 6 at the center of the printed circuit board 2 and a plurality of peripheral welding holes 7 corresponding in number and position to the grounding probes 4.

[0037] The central welding hole 6 and the peripheral welding holes 7 are recessed in the area of the front surface of the printed circuit board 2 opposite the probe unit. The central signal probe 3 and the grounding probes 4 are welded to the printed circuit board 2 via the welding hole unit to form an integral transmission circuit. In a possible implementation, the number of peripheral welding holes 7 is six, corresponding to the six grounding probes 4.

[0038] Further, the insulating unit includes an insulating positioning base 8 fixedly connected to the printed circuit board 2. In a possible implementation, the insulating positioning base 8 is made of a model filled with epoxy resin after 3D printing. The whole is a cylinder, and the cross-sectional diameter is equal to the diameter of the printed circuit board 2, and is bonded to the front surface of the printed circuit board 2 by an adhesive, to ensure the connection stability and sealing of the two.

[0039] Further, Figure 3 A side view of an insulating positioning base 8 of a frequency domain sensor for measuring soil surface water is provided for the embodiment of the present application, as shown in Figure 3 As shown, the insulating positioning base 8 is provided with a positioning hole unit penetrating along the axial direction of the insulating positioning base 8, which is used for positioning and separating the probe unit, and can also ensure the stability of the connection between the probe unit and the printed circuit board 2, and improve the installation convenience. Specifically, the positioning hole unit includes a center positioning hole 9 located at the center of the insulating positioning base 8, and a plurality of outer peripheral positioning holes 10 corresponding to the number of ground probes 4 and located opposite to each other. The diameter of the center positioning hole 9 is slightly larger than that of the center signal probe 3, and the diameter of the outer peripheral positioning hole 10 is slightly larger than that of the ground probe 4. In the case of complete assembly, the center signal probe 3 penetrates through the center positioning hole 9 to connect the center soldering hole 6, and each ground probe 4 penetrates through an outer peripheral positioning hole 10 to connect an outer peripheral soldering hole 7.

[0040] Further, the plurality of ground probes 4 are equidistantly arranged along the periphery of the center signal probe 3, which means that the linear distance between each adjacent two ground probes 4 is equal, and the distance between each ground probe 4 and the center signal probe 3 is equal. Based on this design, it is helpful to form a uniform electromagnetic field, reduce interference and attenuation in the signal transmission process, and ensure that the signal receives the least interference in the transmission process. This layout helps to maintain the integrity and stability of the signal, thereby improving the performance of the system.

[0041] Further, the length of the center signal probe 3 is less than that of the ground probe 4. The length of the center signal probe 3 will affect its impedance characteristics. A shorter center signal probe 3 can reduce signal reflection and distortion. At the same time, a too long center signal probe 3 can cause multiple reflections and resonances of the signal inside the probe, which will increase the noise component of the signal and reduce the purity of the signal. Therefore, a shorter center signal probe 3 helps to reduce these effects, thereby maintaining the clarity and accuracy of the signal.

[0042] In a possible implementation, the center signal probe 3 and the ground probe 4 are both made of stainless steel. At the same time, the length difference between the center signal probe 3 and the ground probe 4 is preferably 5MM. That is, the length of the center signal probe 3 is 50MM, and the length of the ground probe 4 is 65MM. The thickness of the insulating positioning base 8 is 10MM. Therefore, the exposed length of the center signal probe 3 is 40MM, and the exposed length of the ground probe 4 is 45MM.

[0043] The frequency domain sensor in the application ensures efficient and accurate signal transmission by setting a center signal probe 3, and the surrounding of multiple grounding probes 4 further enhances the stability of signal transmission, reduces signal attenuation and distortion, and cooperates with the printed circuit board 2 to simplify the traditional multiplexer with channel switching function into a circuit board, which reduces noise sources while communicating the probe unit with the data analysis device 1, and shields the probe unit by setting the insulating positioning base 8, effectively isolates the electromagnetic field between each probe in the probe unit and the probe unit and the external environment, prevents signal interference and cross-influence between them, and further ensures measurement accuracy.

[0044] In the description of the application, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application. Unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the communication between two elements inside. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0045] It should be noted that in the present application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the sentence "including a…" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0046] The foregoing detailed description of the application has been presented for purposes of illustration and description. Various modifications and changes can be made to these embodiments without departing from the spirit and scope of the application. It is intended that the scope of the application should not be limited by the particular representative embodiments described above.

Claims

1. A frequency domain sensor for measuring soil surface layer moisture, characterized in that, The utility model relates to a data analysis device (1) and a sampling assembly connected to the input end of the data analysis device (1). The sampling assembly comprises a printed circuit board (2) and an insulating unit located on the side of the printed circuit board (2) away from the data analysis device (1), and the insulating unit is provided with a probe unit comprising a central signal probe (3) and a plurality of ground probes (4) arranged along the circumference of the central signal probe (3). The printed circuit board (2) is provided with an analysis device connector (5) on the side close to the data analysis device (1). The printed circuit board (2) is provided with a solder hole unit opposite the position of the probe unit for connecting the probe unit.

2. A frequency domain sensor for measuring soil surface moisture as claimed in claim 1, wherein, The solder hole unit comprises a central solder hole (6) located at the center of the printed circuit board (2) and a plurality of peripheral solder holes (7) corresponding in number and position to the ground probes (4).

3. A frequency domain sensor for measuring soil surface moisture as claimed in claim 1, wherein, The insulating unit comprises an insulating positioning base (8) fixedly connected to the printed circuit board (2).

4. A frequency domain sensor for measuring soil surface moisture as claimed in claim 3, wherein, The insulating positioning base (8) is provided with a positioning hole unit passing through the insulating positioning base (8) axially.

5. A frequency domain sensor for measuring soil surface moisture as claimed in claim 4, wherein, The positioning hole unit comprises a central positioning hole (9) located at the center of the insulating positioning base (8) and a plurality of peripheral positioning holes (10) corresponding in number and position to the ground probes (4).

6. A frequency domain sensor for measuring soil surface moisture as claimed in claim 5, wherein, The central signal probe (3) penetrates the central positioning hole (9) to connect the central solder hole (6), and each ground probe (4) penetrates a peripheral positioning hole (10) to connect a peripheral solder hole (7).

7. A frequency domain sensor for measuring soil surface moisture as claimed in claim 6, wherein, The plurality of ground probes (4) are equidistantly arranged along the circumference of the central signal probe (3).

8. A frequency domain sensor for measuring soil surface moisture as claimed in claim 7, wherein, The length of the central signal probe (3) is less than the length of the ground probes (4).

9. A frequency domain sensor for measuring soil surface moisture as claimed in claim 1, wherein, ​ 10. A frequency domain sensor for measuring soil surface moisture as claimed in claim 9, wherein, ​

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