EMNZ medium-based temperature and humidity sensor and preparation method thereof

Abstract

The application discloses a temperature and humidity sensor based on an EMNZ medium and a preparation method thereof, and comprises a first substrate integrated waveguide structure, a second substrate integrated waveguide structure and an air waveguide structure; the air waveguide structure is arranged between the first substrate integrated waveguide structure and the second substrate integrated waveguide structure, the internal medium of the air waveguide structure is air, and a plurality of measuring areas are arranged in the air waveguide structure; the measuring areas are used for adding doped materials of substances to be measured; the outer edges of the first substrate integrated waveguide structure and the second substrate integrated waveguide structure are each provided with a plurality of metallized through holes; the first substrate integrated waveguide structure is provided with a first coaxial feeder, and the second substrate integrated waveguide structure is provided with a second coaxial feeder. The application solves the technical problems of low measuring precision and low measuring efficiency of the sensor in the prior art.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a temperature and humidity sensor based on EMNZ medium and its fabrication method. Background Technology

[0002] With the rapid development of the Internet of Things in the power sector, smart homes, and smart cities, real-time monitoring of environmental temperature, humidity, and harmful gases is necessary. To reduce costs and improve measurement accuracy, sensors for simultaneously monitoring changes in multiple environmental parameters have been proposed.

[0003] EMNZ medium is a medium with near-zero relative permittivity and relative permeability. ENZ medium is a medium with near-zero refractive index. Currently, for sensors that measure multiple parameters, such as temperature and humidity sensors, there are still problems such as not considering the coupling effect between two resonators, the resonators being affected by factors other than the measured parameters, and the inability to independently adjust different measured parameters, resulting in a large mean square error of the detected temperature and humidity parameters.

[0004] Therefore, there is an urgent need for a sensor that can effectively and accurately measure the temperature and humidity of the environment. Summary of the Invention

[0005] This invention provides a temperature and humidity sensor based on EMNZ medium and its fabrication method, in order to solve the technical problems of low measurement accuracy and low measurement efficiency in existing sensors.

[0006] To address the aforementioned technical problems, this invention provides a temperature and humidity sensor based on EMNZ medium, comprising: a first substrate integrated waveguide structure, a second substrate integrated waveguide structure, and an air waveguide structure;

[0007] The air waveguide structure is disposed between the first substrate integrated waveguide structure and the second substrate integrated waveguide structure. The internal medium of the air waveguide structure is air, and several measurement areas are disposed inside. The measurement areas are used to add doping materials of the substance to be measured.

[0008] Both the first substrate integrated waveguide structure and the second substrate integrated waveguide structure have a plurality of metallized vias on their outer edges; the first substrate integrated waveguide structure has a first coaxial feed line, and the second substrate integrated waveguide structure has a second coaxial feed line.

[0009] As a preferred embodiment, the air waveguide structure is a cuboid structure that is open at both ends and closed by metal plates on all sides;

[0010] The first substrate integrated waveguide structure and the second substrate integrated waveguide structure are respectively disposed at the open end of the air waveguide structure.

[0011] As a preferred embodiment, the first substrate integrated waveguide structure includes: an upper metal plate, a lower metal plate, and an intermediate matrix layer disposed between the upper metal plate and the lower metal plate;

[0012] The first coaxial feed line is not connected to the lower metal plate, and the lower metal plate is provided with a first through hole through which the first coaxial feed line passes.

[0013] As a preferred embodiment, the second substrate integrated waveguide structure includes: an upper metal plate, a lower metal plate, and an intermediate matrix layer disposed between the upper metal plate and the lower metal plate;

[0014] The second coaxial feed line is not connected to the lower metal plate, and the lower metal plate is provided with a second through hole through which the second coaxial feed line passes.

[0015] As a preferred embodiment, the metallized vias are uniformly disposed on the outer edges of the first substrate integrated waveguide structure and the second substrate integrated waveguide structure.

[0016] As a preferred embodiment, the number of measurement areas set inside the air waveguide structure is 2.

[0017] As a preferred option, the doping materials of the substance to be measured added to the measurement area are different.

[0018] Accordingly, the present invention also provides a method for fabricating a temperature and humidity sensor based on EMNZ medium, used to fabricate the temperature and humidity sensor based on EMNZ medium as described in any of the above claims, comprising:

[0019] Depending on the operating frequency band of the temperature and humidity sensor to be fabricated, it can be prepared using PCB processing technology, wire EDM, or photolithography.

[0020] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0021] The technical solution of this invention adds a doped material to a near-zero refractive index (ENZ) cavity in an air waveguide structure, so that the electric field is mainly concentrated at the cylindrical edge of the doped material measurement area, while the magnetic field is mainly concentrated inside the cylinder of the doped material measurement area. That is, the equivalent relative permittivity and equivalent relative permeability of the doped ENZ cavity are both zero, thus forming an equivalent EMNZ sensing structure. By exciting the air waveguide structure, metallized vias and coaxial feed lines on the first and second substrate integrated waveguides are introduced, thereby achieving high-precision sensing measurement of the relative permittivity through the locally enhanced electric field around the doped material. At the same time, the field enhancement and uniform phase distribution result in high sensitivity of the sensor to small changes in ambient temperature and humidity, thereby effectively improving the measurement accuracy of the sensor. Attached Figure Description

[0022] Figure 1 This is a structural diagram of the temperature and humidity sensor based on EMNZ medium proposed in the embodiments of the present invention.

[0023] Figure 2 This is a side cross-sectional view of the temperature and humidity sensor based on EMNZ medium proposed in the embodiments of the present invention.

[0024] Figure 3 This is a top view of the temperature and humidity sensor based on EMNZ medium proposed in the embodiments of the present invention.

[0025] Figure 4 This is a graph showing the transmission coefficient of the temperature and humidity sensor based on EMNZ medium proposed in this embodiment of the invention after temperature change.

[0026] Figure 5 This is a graph showing the transmission coefficient of the temperature and humidity sensor based on EMNZ medium proposed in this embodiment of the invention after the humidity has been changed.

[0027] Figure 6 This is a transmission coefficient diagram of the temperature and humidity sensor based on EMNZ medium proposed in this embodiment of the invention after simultaneously changing the temperature and humidity.

[0028] Figure 7 This is a comparison chart and mean square error of the predicted and expected values ​​of the ambient temperature and low-loss material test set of the temperature and humidity sensor based on EMNZ medium proposed in the embodiments of the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] Please refer to Figure 1 and 2 The temperature and humidity sensor based on EMNZ medium provided in this embodiment of the invention includes: a first substrate integrated waveguide structure (1), a second substrate integrated waveguide structure (2), and an air waveguide structure (3).

[0032] The air waveguide structure (3) is disposed between the first substrate integrated waveguide structure (1) and the second substrate integrated waveguide structure (2). The internal medium of the air waveguide structure (3) is air, and several measurement areas (15) and (16) are provided inside. The measurement areas (15) and (16) are used to add doping materials of the substance to be measured.

[0033] It should be noted that the air waveguide structure (3) is used to simulate the ENZ cavity. The air waveguide structure (3) is excited by the first substrate integrated waveguide structure (1) and the second substrate integrated waveguide structure (2) and operates in TE mode. 10 Near the modulus cutoff frequency.

[0034] As a preferred embodiment, the air waveguide structure (3) is a cuboid structure with open ends and closed by metal plates on all sides; the first substrate integrated waveguide structure (1) and the second substrate integrated waveguide structure (2) are respectively disposed at the open end of the air waveguide structure (3).

[0035] It should be noted that the air waveguide structure (3) is made of metal and is a cuboid structure that is open at both ends but closed on all sides. The closed metal plates can restrict the propagation of electromagnetic waves. The upper metal plate (5) is on top, the lower metal plate (6) is on the bottom, the metal plate (14) is in front, and the metal plate (13) is at the back. The specific physical dimensions of the air waveguide structure (3) are selected according to the operating frequency (operating mode) of the designed air waveguide structure (3).

[0036] Furthermore, the doped material in the air waveguide structure (3) is the object of the sensing study. When doped material is added to the rectangular air waveguide, the electric field is mainly concentrated at the edge of the doped cylinder, while the magnetic field is mainly concentrated inside the doped cylinder. That is, the equivalent relative permittivity and equivalent relative permeability of the doped ENZ cavity are both zero, forming an EMNZ medium sensing structure. This field enhancement and uniform phase distribution result in the sensor having high sensitivity to small changes in ambient temperature and humidity. Therefore, the relative permittivity of the doped material is changed for sensing measurement.

[0037] As a preferred embodiment, the number of measurement areas (15) and (16) set inside the air waveguide structure (3) is 2.

[0038] It is understandable that by adding double doping to the near-zero refractive index (ENZ) cavity of the air waveguide structure (3) to make it equivalent to an EMNZ sensing structure, the electric field enhanced by the local field around the doped material can achieve high-precision sensing measurement of the relative permittivity.

[0039] As a preferred embodiment, the doping materials of the substances to be measured added to the measurement areas (15) and (16) are different.

[0040] It should be noted that in this embodiment, by introducing different doping materials into the ENZ structure to form an EMNZ structure, the effect of simultaneously and independently measuring temperature and humidity is achieved. This method is simple and effective. Meanwhile, the relative permittivity of the air waveguide structure (3) can change depending on the material being measured.

[0041] In this embodiment, the operating frequency of the temperature and humidity sensor can be adjusted by replacing the material to be measured in the measurement areas (15) and (16) of the air waveguide structure (3). For instructions on replacement, please refer to [link to relevant documentation]. Figure 1 The upper metal plate (5) above the air waveguide structure (3) in the temperature and humidity sensor can be removed directly, which facilitates the replacement of doped materials.

[0042] The outer edges of the first substrate integrated waveguide structure (1) and the second substrate integrated waveguide structure (2) are provided with a plurality of metallized vias (7); the first substrate integrated waveguide structure (1) is provided with a first coaxial feed line (9), and the second substrate integrated waveguide structure (2) is provided with a second coaxial feed line (10).

[0043] It should be noted that in this embodiment, the substrate integrated waveguide (SIW) structure is integrated on one side of the open port of the rectangular air waveguide, and the air waveguide is excited through the metallized via (7) and the first coaxial feed (9) and the second coaxial feed (10).

[0044] As a preferred embodiment, the first substrate integrated waveguide structure (1) includes: an upper metal plate (5), a lower metal plate (6), and an intermediate matrix layer (8) disposed between the upper metal plate (5) and the lower metal plate (6); the first coaxial feed line (9) is not connected to the lower metal plate (6), and the lower metal plate (6) is provided with a first through hole (11) through which the first coaxial feed line (9) passes.

[0045] As a preferred embodiment, the second substrate integrated waveguide structure (2) includes: an upper metal plate (5), a lower metal plate (6), and an intermediate matrix layer (8) disposed between the upper metal plate (5) and the lower metal plate (6); the second coaxial feed line (10) is not connected to the lower metal plate (6), and the lower metal plate (6) is provided with a second through hole (12) through which the second coaxial feed line (10) passes.

[0046] As a preferred embodiment, the metallized vias (7) are uniformly disposed on the outer edges of the first substrate integrated waveguide structure (1) and the second substrate integrated waveguide structure (2).

[0047] In this embodiment, the substrate integrated waveguide (SIW) introduced to excite the air waveguide structure (3) uses a first coaxial feed line (9) and a second coaxial feed line (10) as feed sources to excite the propagation mode of the substrate integrated waveguide. Since the air waveguide structure (3) is composed of four metal plate wall structures and is open at both ends, the physical dimensions of the air waveguide, namely the length, width and thickness, can be reasonably set according to the required operating frequency of the air waveguide structure (3) so that the first substrate integrated waveguide and the second substrate integrated waveguide can be excited at the open ends of the air waveguide structure (3).

[0048] Further, please refer to Figure 3 The coaxial feed line is introduced to excite the substrate integrated waveguide to work normally. The coaxial feed line is not connected to the metal of the substrate integrated waveguide. Therefore, vias are set on the metal plate on the bottom side of the substrate integrated waveguide to ensure the normal operation of the coaxial feed line.

[0049] Please see Figure 4 As an exemplary solution in this embodiment, assuming the ambient temperature is 35°C, the relative permittivity of distilled water will not change. Only when the relative humidity of the environment is changed, the relative permittivity increases from 2 to 4.5 in increments of 0.1. The second resonant frequency shows almost no shift, while the first resonant frequency red-shifts with the increase of the relative permittivity of the polyimide material. This demonstrates that the sensor can independently control the relative permittivity of the polyimide material to achieve measurement of a single material.

[0050] Please see Figure 5 As another exemplary solution in this embodiment, assuming the relative humidity of the environment is 68%, the relative permittivity of the polyimide material does not change. Only when the ambient temperature is changed, the relative permittivity of distilled water increases sequentially from 60 to 74, with a step value of 1. The first resonant frequency point shows almost no shift, while the second resonant frequency point redshifts as the relative permittivity of distilled water increases. This demonstrates that the sensor can independently control the relative permittivity of distilled water to achieve measurement of a single material.

[0051] Please see Figure 6 As another exemplary solution in this embodiment, when the relative permittivity of the low-loss material and the ambient temperature are changed simultaneously—that is, the relative permittivity of the low-loss material increases sequentially from 2 to 7 in steps of 0.2, and the relative permittivity of distilled water increases sequentially from 60 to 74 in steps of 1—the first resonant frequency red-shifts as the relative permittivity of the low-loss material increases, and the second resonant frequency red-shifts as the relative permittivity of the distilled water increases.

[0052] Therefore, based on the above exemplary solution, the temperature and humidity sensor in this embodiment can simultaneously measure the temperature of low-loss materials and the environment.

[0053] Please see Figure 7 , Figure 7 The left side indicates that the predicted value and the expected value are in good agreement. Figure 7 The mean square error of the temperature displayed on the right is between ±0.1, and the mean square error of the low-loss material is between ±0.3. It can be seen that the dual-channel EMNZ medium sensor can have high measurement accuracy when multiple parameters change simultaneously.

[0054] Implementing the above embodiments has the following effects:

[0055] The technical solution of this invention adds a doped material to a near-zero refractive index (ENZ) cavity in an air waveguide structure, so that the electric field is mainly concentrated at the cylindrical edge of the doped material measurement area, while the magnetic field is mainly concentrated inside the cylindrical part of the doped material measurement area. That is, the equivalent relative permittivity and equivalent relative permeability of the doped ENZ cavity are both zero, thus forming an equivalent EMNZ sensing structure. By exciting the air waveguide structure, metallized vias and coaxial feeds on the first and second substrate integrated waveguides are introduced, thereby achieving high-precision sensing measurement of the relative permittivity through the locally enhanced electric field around the doped material. At the same time, the field enhancement and uniform phase distribution result in high sensitivity of the sensor to small changes in ambient temperature and humidity, thereby effectively improving the measurement accuracy of the sensor.

[0056] Example 2

[0057] Accordingly, the present invention also provides a method for fabricating a temperature and humidity sensor based on EMNZ medium, used to fabricate the temperature and humidity sensor based on EMNZ medium as described in any of the above claims, comprising:

[0058] Depending on the operating frequency band of the temperature and humidity sensor to be fabricated, it can be prepared using PCB processing technology, wire EDM, or photolithography.

[0059] It should be noted that, since the temperature and humidity sensors need to measure different frequency bands, the physical dimensions of the air waveguide, namely its length, width, and thickness, should be reasonably set according to the required operating frequency of the rectangular air waveguide structure. This ensures that the physical dimensions of the air waveguide structure guarantee that the temperature and humidity sensor is suitable for different operating frequencies.

[0060] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A temperature and humidity sensor based on EMNZ medium, characterized in that, include: First substrate integrated waveguide structure, second substrate integrated waveguide structure and air waveguide structure; The air waveguide structure is disposed between the first substrate integrated waveguide structure and the second substrate integrated waveguide structure. The internal medium of the air waveguide structure is air, and several measurement areas are provided inside. The measurement areas are used to add doping materials of the substance to be measured. The air waveguide structure is a cuboid structure that is open at both ends and closed by metal plates on all sides. The first substrate integrated waveguide structure and the second substrate integrated waveguide structure are respectively disposed at the open end of the air waveguide structure; The first substrate integrated waveguide structure includes: an upper metal plate, a lower metal plate, and an intermediate matrix layer disposed between the upper metal plate and the lower metal plate; a first coaxial feed line is not connected to the lower metal plate, and the lower metal plate is provided with a first through hole through which the first coaxial feed line passes. The second substrate integrated waveguide structure includes: an upper metal plate, a lower metal plate, and an intermediate matrix layer disposed between the upper metal plate and the lower metal plate; the second coaxial feed line is not connected to the lower metal plate, and the lower metal plate is provided with a second through hole through which the second coaxial feed line passes; The number of measurement regions set inside the air waveguide structure is 2; the doping materials of the substance to be measured added to the measurement regions are different; Both the first substrate integrated waveguide structure and the second substrate integrated waveguide structure have a plurality of metallized vias on their outer edges; the first substrate integrated waveguide structure has a first coaxial feed line, and the second substrate integrated waveguide structure has a second coaxial feed line.

2. The temperature and humidity sensor based on EMNZ medium as described in claim 1, characterized in that, The metallized vias are uniformly disposed on the outer edges of the first substrate integrated waveguide structure and the second substrate integrated waveguide structure.

3. A method for fabricating a temperature and humidity sensor based on EMNZ medium, characterized in that, For fabricating a temperature and humidity sensor based on EMNZ medium as described in any one of claims 1-2, comprising: Depending on the operating frequency band of the temperature and humidity sensor to be fabricated, it can be prepared using PCB processing technology, wire EDM, or photolithography.

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