A humidity sensor

Abstract

The application provides a humidity sensor, comprising a substrate, a power divider and a power combiner, a first microstrip line, a first interdigital capacitor plate, a second microstrip line, a second interdigital capacitor plate and a humidity sensitive material layer; the power divider and the power combiner are arranged on the substrate, and the power divider and the power combiner are opposite; one end of the power divider close to the power combiner is connected with the first microstrip line, and a preset distance is formed between the first microstrip line and the substrate; the first interdigital capacitor plate is arranged on the first microstrip line; one end of the power combiner close to the power divider is connected with the second microstrip line, and a preset distance is formed between the second microstrip line and the substrate. One technical effect of the application is that the design is reasonable, and the measurement precision and the adjustment range of the humidity are very convenient.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of microelectronic devices, and particularly relates to a humidity sensor. BACKGROUND

[0002] Humidity sensors are widely used in meteorological detection, industrial control, home monitoring and other fields. With the trend of miniaturization and microfabrication, humidity sensors have been developing rapidly in recent years. The combination of new structures with humidity sensors is an important means to improve sensor performance. New humidity sensors combined with MEMS (Micro Electromechanical System) structures have the advantages of small size, easy integration, low cost, high precision, etc.

[0003] However, the current humidity sensor is greatly affected by temperature during detection, and the detection range cannot be adjusted, which is very inconvenient to use. SUMMARY

[0004] The present application aims to at least solve one of the technical problems existing in the prior art, and provides a new technical solution for a humidity sensor.

[0005] According to one aspect of the present application, a humidity sensor is provided, comprising:

[0006] a substrate;

[0007] a power divider and a power combiner, both of which are arranged on the substrate, and the power divider and the power combiner are opposite to each other;

[0008] a first microstrip line and a first interdigital capacitor plate, the power divider is connected to the first microstrip line at one end close to the power combiner, and a predetermined distance is formed between the first microstrip line and the substrate; the first interdigital capacitor plate is arranged on the first microstrip line;

[0009] a second microstrip line and a second interdigital capacitor plate, the power combiner is connected to the second microstrip line at one end close to the power divider, and a predetermined distance is formed between the second microstrip line and the substrate; the second interdigital capacitor plate is arranged on the second microstrip line, and the interdigital fingers of the second interdigital capacitor plate and the interdigital fingers of the first interdigital capacitor plate are interlaced with each other; the first interdigital capacitor and the second interdigital capacitor together form an interdigital capacitor structure;

[0010] a humidity-sensitive material layer, which covers one side of the first microstrip line away from the first interdigital capacitor plate;

[0011] The humidity sensor is placed in the detection environment, when the humidity of the detection environment increases, the humidity sensitive material layer expands and generates stress at the interface between the humidity sensitive material layer and the first microstrip line, so as to drive the first interdigital capacitor plate to move towards the second interdigital capacitor plate, the capacitance value of the interdigital capacitor structure increases, so that the output power of the power combiner increases, and the humidity of the detection environment is obtained according to the output power.

[0012] Optionally, the power divider comprises a divider input branch, a first divider output branch and a second divider output branch; the first divider output branch and the second divider output branch are connected with one end of the divider input branch close to the power combiner; one end of the first divider output branch away from the divider input branch is connected with one of the first microstrip lines; the other end of the second divider output branch away from the divider input branch is connected with the other of the first microstrip lines; each of the first microstrip lines is provided with a first interdigital capacitor plate, and each of the first microstrip lines is provided with a humidity sensitive material layer away from the first interdigital capacitor plate;

[0013] The power combiner comprises a first combiner input branch, a second combiner input branch and a combiner output branch; the first combiner input branch and the second combiner input branch are connected with one end of the combiner output branch close to the power divider; one end of the first combiner input branch away from the combiner output branch is connected with one of the second microstrip lines; the other end of the second combiner input branch away from the combiner output branch is connected with the other of the second microstrip lines; each of the second microstrip lines is provided with a second interdigital capacitor plate matched with the first interdigital capacitor plate.

[0014] Optionally, the first microstrip line and the second microstrip line form a concentric circular arc structure, and the radius of the first microstrip line is greater than the radius of the second microstrip line.

[0015] Optionally, the first divider output branch and the second divider output branch are connected and form a first arc structure, and the radius of the first arc structure is the same as the radius of the first microstrip line.

[0016] Optionally, the first combiner input branch and the second combiner input branch are connected and form a second arc structure, and the radius of the second arc structure is the same as the radius of the second microstrip line.

[0017] Optionally, the divider input branch and the combiner output branch are located on the same straight line.

[0018] Optionally, the length of the first combiner input branch is equal to the length of the second combiner input branch; and the length of the first divider output branch is equal to the length of the second divider output branch.

[0019] Optionally, an anchor region is further included, one end of the second microstrip line away from the power combiner is connected to the anchor region, and the anchor region is fixed to the substrate.

[0020] Optionally, the material of the humidity-sensitive material layer is polydimethylsiloxane or polyimide.

[0021] Optionally, the first interdigital capacitor electrode plate includes three interdigital plates, and the distances between adjacent interdigital plates are the same; and the second interdigital capacitor electrode plate includes four interdigital plates, and the distances between adjacent interdigital plates are the same.

[0022] The three interdigital plates of the first interdigital capacitor electrode plate are respectively inserted into three gaps formed by the four interdigital plates of the second interdigital capacitor electrode plate.

[0023] One technical effect of the present application is that:

[0024] In the embodiments of the present application, in a first aspect, the humidity sensor can adjust the measurement accuracy and detection range of humidity by adjusting the interdigital capacitor structure and the thickness of the humidity-sensitive material layer according to different environmental requirements, and the design is very flexible; in a second aspect, the humidity sensor uses a humidity-sensitive material layer, and since the humidity-sensitive material layer is not affected by temperature and other environments, and the accuracy can be adjusted by adjusting the input power, the humidity sensor has the advantages of strong anti-interference ability and high measurement accuracy; in a third aspect, the humidity sensor has a novel structure, small size, and stable performance, and can realize high reliability and miniaturization application requirements; and in a fourth aspect, the humidity sensor is fully compatible with microelectronic processing technology, which is conducive to the miniaturization and mass production of the humidity sensor. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 FIG. 1 is a structural schematic diagram of a humidity sensor according to an embodiment of the present application;

[0026] Figure 2 FIG. 2 is a structural schematic diagram of the humidity sensor along a direction A-A; Figure 1 FIG. 3 is a structural schematic diagram of the humidity sensor along a direction B-B.

[0027] Figure 3 FIG. 4 is a structural schematic diagram of the humidity sensor along a direction C-C. Figure 1

[0028] In the figure: 1, substrate; 2, power divider; 21, divider input branch; 22, first divider output branch; 23, second divider output branch; 3, power combiner; 31, first combiner input branch; 32, second combiner input branch; 33, combiner output branch; 41, first microstrip line; 42, second microstrip line; 51, first interdigital capacitor electrode plate; 52, second interdigital capacitor electrode plate; 6, humidity-sensitive material layer; 7, anchor region. DETAILED DESCRIPTION​

[0029] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0030] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0031] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0032] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0033] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0034] like Figures 1 to 3 As shown in the figure, this application provides a humidity sensor for detecting humidity.

[0035] Specifically, the humidity sensor comprises a substrate 1, a power divider 2, a power combiner 3, a first microstrip line 41, a first interdigital capacitor plate 51, a second microstrip line 42, a second interdigital capacitor plate 52 and a humidity-sensitive material layer 6. The power divider 2 is used for dividing power, and the power combiner 3 is used for combining power.

[0036] Further specifically, the power divider 2 and the power combiner 3 are both arranged on the substrate 1, and the power divider 2 and the power combiner 3 are opposite. The power divider 2 and the power combiner 3 are firmly fixed on the substrate 1 to ensure the stability of their functions.

[0037] The power divider 2 is connected to the first microstrip line 41 at one end close to the power combiner 3, and a preset distance is formed between the first microstrip line 41 and the substrate 1, i.e. the first microstrip line 41 is arranged above the substrate 1 in a suspended manner; the first interdigital capacitor plate 51 is arranged on the first microstrip line 41; the power combiner 3 is connected to the second microstrip line 42 at one end close to the power divider 2, and a preset distance is formed between the second microstrip line 42 and the substrate 1, i.e. the second microstrip line 42 is arranged above the substrate 1 in a suspended manner; the second interdigital capacitor plate 52 is arranged on the second microstrip line 42, and the interdigital fingers of the second interdigital capacitor plate 52 and the interdigital fingers of the first interdigital capacitor plate 51 are interlaced with each other; the first interdigital capacitor and the second interdigital capacitor jointly constitute an interdigital capacitor structure; and the humidity-sensitive material layer 6 covers one side of the first microstrip line 41 away from the first interdigital capacitor plate 51. The humidity-sensitive material layer 6 expands with the increase of humidity in the detection environment, and the expansion rate of the humidity-sensitive material layer 6 is positively correlated with the humidity.

[0038] It should be noted that the first microstrip line 41, the second microstrip line 42, the humidity-sensitive material layer 6, the first interdigital capacitor plate 51 and the second interdigital capacitor plate 52 are all in a suspended state relative to the substrate 1, so as to facilitate the first interdigital capacitor plate 51 to move close to the second interdigital capacitor plate 52, thereby changing the capacitance value of the interdigital capacitor structure.

[0039] The humidity sensor is placed in a detection environment. When the humidity in the detection environment increases, the humidity-sensitive material layer 6 expands and generates stress at the interface between the humidity-sensitive material layer 6 and the first microstrip line 41, so as to drive the first interdigital capacitor plate 51 to move close to the second interdigital capacitor plate 52. The increase of the capacitance value of the interdigital capacitor structure causes the output power of the power combiner 3 to increase, and the humidity in the detection environment is obtained according to the output power. The humidity in the detection environment is detected by the humidity sensor through the physical change of the humidity-sensitive material, which is simple to operate. Meanwhile, the humidity-sensitive material layer 6 is not easily affected by the temperature in the detection environment, and the detection result is relatively accurate.

[0040] Therefore, the humidity sensor formed by the power divider 2, the power combiner 3 and the interdigital capacitor structure can convert the humidity of the external detection environment into the output power of the power combiner 3 while meeting the high precision, and the humidity of the detection environment can be detected by measuring the output power, which is simple to operate.

[0041] Further, the humidity sensor can adjust the coupling power by adjusting the input power according to the requirements of the detection environment, further adjust the detection precision of the humidity sensor, and realize the high-precision measurement of the humidity. In addition, the humidity sensor has the advantages of flexible design, simple structure, high precision, small size, process compatibility and the like.

[0042] In the embodiments of the present application, in a first aspect, the humidity sensor can adjust the measurement precision and the detection range of the humidity by adjusting the thickness of the interdigital capacitor structure and the humidity-sensitive material layer 6 according to different environmental requirements, and the design is very flexible; in a second aspect, the humidity sensor uses the humidity-sensitive material layer 6, and since the humidity-sensitive material layer 6 is not affected by the temperature and other environments, and the precision can be adjusted by adjusting the input power, the humidity sensor has the advantages of strong anti-interference ability and high measurement precision; in a third aspect, the humidity sensor has a novel structure, small size and stable performance, and can realize the application requirements of high reliability and miniaturization; in a fourth aspect, the humidity sensor is fully compatible with the microelectronic processing technology, which is conducive to the miniaturization and mass production of the humidity sensor.

[0043] Optionally, the power divider 2 includes a divider input branch 21, a first divider output branch 22 and a second divider output branch 23; the first divider output branch 22 and the second divider output branch 23 are both connected to one end of the divider input branch 21 close to the power combiner 3; one first microstrip line 41 is connected to the end of the first divider output branch 22 away from the divider input branch 21; another first microstrip line 41 is connected to the end of the second divider output branch 23 away from the divider input branch 21; each first microstrip line 41 is provided with a first interdigital capacitor plate 51, and each first microstrip line 41 is provided with a humidity-sensitive material layer 6 away from the first interdigital capacitor plate 51;

[0044] The power combiner 3 comprises a first combiner input branch 31, a second combiner input branch 32 and a combiner output branch 33; the first combiner input branch 31 and the second combiner input branch 32 are connected to one end of the combiner output branch 33 close to the power divider 2; one of the second microstrip lines 42 is connected to the end of the first combiner input branch 31 away from the combiner output branch 33; another of the second microstrip lines 42 is connected to the end of the second combiner input branch 32 away from the combiner output branch 33; each of the second microstrip lines 42 is provided with a second interdigital capacitor plate 52 matched with the first interdigital capacitor plate 51.

[0045] In the above embodiment, not only the power is divided through the divider input branch 21, the first divider output branch 22 and the second divider output branch 23, but also the power is combined through the first combiner input branch 31, the second combiner input branch 32 and the combiner output branch 33, so that when the humidity of the detection environment increases, the capacitance values of the two interdigital capacitor structures change and are output by the power combiner 3, the humidity of the detection environment is obtained according to the output power of the power combiner 3, and the detection result is more accurate. Even a slight change in humidity can easily cause the output power of the power combiner 3 to change through the two interdigital capacitor structures, which is beneficial to improve the accuracy of humidity detection.

[0046] In other embodiments, the power divider 2 comprises a plurality of divider output branches, and the power combiner 3 comprises a plurality of combiner input branches; one of the first microstrip lines 41 is connected to each of the divider output branches; one of the second microstrip lines 42 is connected to each of the combiner input branches; a plurality of interdigital capacitor structures are formed by arranging the first interdigital capacitor substrate 1 on each of the first microstrip lines 41 and arranging the corresponding second interdigital capacitor substrate 1 on each of the second microstrip lines 42, so that when the humidity of the detection environment changes, the capacitance values of the plurality of interdigital capacitor structures can change, the output power of the power combiner 3 can change significantly, which is beneficial to realize the detection of humidity and improve the detection accuracy of the humidity sensor.

[0047] Optionally, the first microstrip line 41 and the second microstrip line 42 form a concentric circular arc structure, and the radius of the first microstrip line 41 is greater than the radius of the second microstrip line 42. This makes it possible to generate stress at the interface between the humidity-sensitive material layer 6 and the first microstrip line 41 when the humidity-sensitive material layer 6 expands, so as to quickly drive the first interdigital capacitor plate 51 to move towards the second interdigital capacitor plate 52, thereby realizing the change of the capacitance value of the interdigital capacitor structure, and further causing the output power of the power combiner 3 to increase, so as to realize the detection of the humidity of the detection environment.

[0048] For example, according to the requirement of detecting the environment, the measurement accuracy and the detection range of the humidity are adjusted by adjusting the input power of the power divider 2, the curvature of the first interdigital capacitor plate 51 and the second interdigital capacitor plate 52, and the thickness of the humidity-sensitive material layer 6, and the adjustment mode is very simple.

[0049] It should be noted that, since the first interdigital capacitor plate 51 is arranged on the first microstrip line 41, and the second interdigital capacitor plate 52 is arranged on the second microstrip line 42, the curvature of the concentric circular arc structure formed by the first microstrip line 41 and the second microstrip line 42 is adjusted to adjust the curvature of the first interdigital capacitor plate 51 and the second interdigital capacitor plate 52, which is simple to operate and helps to adjust the detection range and detection accuracy of the humidity sensor.

[0050] Optionally, the first divider output branch 22 and the second divider output branch 23 are connected and form a first arc structure, and the radius of the first arc structure is the same as the radius of the first microstrip line 41. This helps to optimize the structure of the power divider 2, ensures the stability of the connection between the power divider 2 and the first microstrip line 41, and makes it easy to change the capacitance value of the interdigital capacitor structure when the first microstrip line 41 moves and drives the first interdigital capacitor substrate 1 to move towards the second interdigital capacitor substrate 1, thereby helping to obtain the humidity of the detected environment by changing the power output by the power combiner 3, which is simple to operate and easy to implement.

[0051] Optionally, the first combiner input branch 31 and the second combiner input branch 32 are connected and form a second arc structure, and the radius of the second arc structure is the same as the radius of the second microstrip line 42. This helps to optimize the structure of the power combiner 3, ensures the stability of the connection between the power combiner 3 and the second microstrip line 42, and enables accurate changes in the capacitance value of the interdigital capacitor structure when the first microstrip line 41 moves and drives the first interdigital capacitor substrate 1 to move towards the second interdigital capacitor substrate 1, thereby helping to accurately obtain the humidity of the detected environment by changing the power output by the power combiner 3, which is simple to operate and easy to implement.

[0052] Optionally, the divider input branch 21 and the combiner output branch 33 are located on the same straight line. This helps to arrange the power divider 2 and the power combiner 3 on the substrate 1, and facilitates stable input and output of power.

[0053] Optionally, the length of the first combiner input branch 31 is equal to the length of the second combiner input branch 32; the length of the first divider output branch 22 is equal to the length of the second divider output branch 23. This makes the humidity sensor have a symmetrical structure, so that the two interdigital capacitor structures can have the same amount of change in capacitance value when the humidity increases, thereby increasing the amount of change in output power of the power combiner 3 to achieve accurate measurement of humidity.

[0054] Optionally, further comprising an anchor area 7, one end of the second microstrip line 42 away from the power combiner 3 is connected to the anchor area 7, and the anchor area 7 is fixed to the substrate 1. The anchor area 7 can fix the second microstrip line 42 and ensure that the second microstrip line 42 has good stability when the first interdigital capacitor plate 51 moves towards the second interdigital capacitor plate 52, so that the capacitance value of the interdigital capacitor structure changes stably.

[0055] Optionally, the material of the humidity-sensitive material layer 6 is polydimethylsiloxane or polyimide. This makes the humidity-sensitive material layer 6 have a good expansion coefficient, so that when the humidity-sensitive material layer 6 expands, a larger stress can be generated at the interface between the humidity-sensitive material layer 6 and the first microstrip line 41 to drive the first interdigital capacitor plate 51 to move towards the second interdigital capacitor plate 52, thereby changing the capacitance value of the interdigital capacitor structure.

[0056] In the example, the polydimethylsiloxane or polyimide is coated on the surface of the first microstrip line 41 to form the humidity-sensitive material layer 6, so that the humidity-sensitive material layer 6 is formed in a relatively simple manner, and the thickness of the humidity-sensitive material layer 6 can be controlled.

[0057] Optionally, the first interdigital capacitor plate 51 includes three interdigital plates, and the distance between adjacent interdigital plates is the same; the second interdigital capacitor plate 52 includes four interdigital plates, and the distance between adjacent interdigital plates is the same.

[0058] The three interdigital plates of the first interdigital capacitor plate 51 are respectively inserted into the three gaps formed by the four interdigital plates of the second interdigital capacitor plate 52.

[0059] In the above embodiment, the first interdigital capacitor plate 51 and the second interdigital capacitor plate 52 have a good matching relationship, so that when the first interdigital capacitor plate 51 moves towards the second interdigital capacitor plate 52, the capacitance value of the interdigital capacitor structure formed by the first interdigital capacitor plate 51 and the second interdigital capacitor plate 52 can change with temperature, thereby facilitating the detection of the humidity of the detection environment.

[0060] The working principle of the humidity sensor with multiple interdigital capacitor structures is as follows: a power signal is input at one end of the input branch of the power divider 2, and the output branch of the power combiner 3 detects the output signal power, and the multiple humidity-sensitive material layers 6 are exposed to the detection environment. Since the power divider 2 divides the power equally and the capacitance values of each interdigital capacitor structure composed of the first interdigital capacitor plate 51 and the second interdigital capacitor plate 52 are equal, the signal power coupled to the input end of the power combiner 3 of each interdigital capacitor structure is equal. When the humidity of the detection environment increases, each humidity-sensitive material layer 6 expands, causing stress at the interface between the humidity-sensitive material layer 6 and the first microstrip line 41, which drives each first interdigital capacitor plate 51 to move closer to the corresponding second interdigital electrode plate. Further, the capacitance value of each interdigital capacitor structure composed of the first interdigital capacitor plate 51 and the second interdigital capacitor plate 52 increases, thereby increasing the combined power of the power combiner 3. Since the combined power of the power combiner 3 increases, the humidity of the detection environment can be detected by measuring the power at the output end of the power combiner 3.

[0061] In the embodiments of the present application, the humidity sensor has a simple structure, can be processed by microelectronic technology, and the precision of the structure size can reach a high level, and the volume is greatly reduced, which is beneficial to realize the miniaturization of the humidity sensor. Moreover, the humidity sensor uses the humidity-sensitive material layer 6, which is generally not affected by the environment such as temperature, and adjusts the input power through the power divider 2 to realize the purpose of adjustable precision of the humidity sensor, so that the humidity sensor has the advantages of strong anti-interference ability and high measurement precision. In addition, the structure of the humidity sensor is novel, which realizes the application requirements of high reliability and miniaturization, and has important guiding significance for the design of humidity sensors under new structures.

[0062] It can be understood that the above embodiments are only exemplary embodiments adopted for illustrating the principles of the present application, but the present application is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and essence of the present application, and these modifications and improvements are also regarded as the protection scope of the present application.

Claims

1. A humidity sensor, characterized by, The application relates to a humidity sensor. The humidity sensor comprises: a substrate; a power divider and a power combiner, both of which are arranged on the substrate and opposite to each other; a first microstrip line and a first interdigital capacitor plate, one end of the power divider close to the power combiner is connected with the first microstrip line, and a preset distance is formed between the first microstrip line and the substrate; the first interdigital capacitor plate is arranged on the first microstrip line; a second microstrip line and a second interdigital capacitor plate, one end of the power combiner close to the power divider is connected with the second microstrip line, and a preset distance is formed between the second microstrip line and the substrate; the second interdigital capacitor plate is arranged on the second microstrip line, and the interdigital fingers of the second interdigital capacitor plate are interlaced with the interdigital fingers of the first interdigital capacitor plate; the first interdigital capacitor plate and the second interdigital capacitor plate jointly form an interdigital capacitor structure; a humidity-sensitive material layer, which covers one side of the first microstrip line away from the first interdigital capacitor plate; The humidity sensor is placed in a detection environment, when the humidity of the detection environment increases, the humidity-sensitive material layer expands and generates stress at the interface between the humidity-sensitive material layer and the first microstrip line, so as to drive the first interdigital capacitor plate to move close to the second interdigital capacitor plate, the capacitance value of the interdigital capacitor structure increases, so that the output power of the power combiner increases, and the humidity of the detection environment is obtained according to the output power; 2. The humidity sensor of claim 1, wherein The first microstrip line and the second microstrip line form a concentric circular arc structure, and the radius of the first microstrip line is greater than the radius of the second microstrip line. The power divider comprises a divider input branch, a first divider output branch and a second divider output branch; The first divider output branch and the second divider output branch are both connected with one end of the divider input branch close to the power combiner; one end of the first divider output branch away from the divider input branch is connected with one of the first microstrip lines; one end of the second divider output branch away from the divider input branch is connected with the other first microstrip line; each first microstrip line is provided with a first interdigital capacitor plate, and each first microstrip line away from the first interdigital capacitor plate is provided with a humidity-sensitive material layer; 3. The humidity sensor of claim 2, wherein, The power combiner comprises a first combiner input branch, a second combiner input branch and a combiner output branch; the first combiner input branch and the second combiner input branch are both connected with one end of the combiner output branch close to the power divider; one end of the first combiner input branch away from the combiner output branch is connected with one of the second microstrip lines; one end of the second combiner input branch away from the combiner output branch is connected with the other second microstrip line; each second microstrip line is provided with a second interdigital capacitor plate matched with the first interdigital capacitor plate. The first divider output branch and the second divider output branch are connected and form a first arc structure, and the radius of the first arc structure is the same as the radius of the first microstrip line.

4. The humidity sensor of claim 3, wherein, The first combiner input branch and the second combiner input branch are connected and form a second arc structure, and a radius of the second arc structure is the same as a radius of the second microstrip line.

5. The humidity sensor of claim 4, wherein, The distributor input branch and the combiner output branch are located on the same straight line.

6. The humidity sensor of claim 5, wherein, The first combiner input branch and the second combiner input branch are equal in length; and the first distributor output branch and the second distributor output branch are equal in length.

7. The humidity sensor of claim 1, wherein, An anchor area is further included, and one end of the second microstrip line away from the power combiner is connected to the anchor area, and the anchor area is fixed to the substrate.

8. The humidity sensor of claim 1, wherein, The material of the humidity-sensitive material layer is polydimethylsiloxane or polyimide.

9. The humidity sensor of claim 1, wherein, The first interdigital capacitor electrode plate includes three interdigital plates, and distances between adjacent interdigital plates are the same; and the second interdigital capacitor electrode plate includes four interdigital plates, and distances between adjacent interdigital plates are the same. The three interdigital plates of the first interdigital capacitor electrode plate are respectively inserted into three gaps formed by the four interdigital plates of the second interdigital capacitor electrode plate.

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