CN113740353A - Differential humidity sensor based on substrate integrated waveguide dual-entrance resonant cavity - Google Patents
Differential humidity sensor based on substrate integrated waveguide dual-entrance resonant cavity Download PDFInfo
- Publication number
- CN113740353A CN113740353A CN202110876949.8A CN202110876949A CN113740353A CN 113740353 A CN113740353 A CN 113740353A CN 202110876949 A CN202110876949 A CN 202110876949A CN 113740353 A CN113740353 A CN 113740353A
- Authority
- CN
- China
- Prior art keywords
- resonant cavity
- metal
- layer
- holes
- cavity
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N22/00—Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more
- G01N22/04—Investigating moisture content
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
A differential humidity sensor based on a substrate integrated waveguide dual-entrance resonant cavity is characterized in that two re-entrance resonant cavities are longitudinally combined together and respectively serve as a sensing resonant cavity and a reference resonant cavity, a sensitive material capable of adsorbing water molecules in humid air is deposited in a groove region of the sensing resonant cavity, and the water molecules are diffused into the sensitive material to cause the change of intrinsic characteristics of the sensitive material, so that the interaction between a strong induction electric field and a moisture absorption material is excited in the sensing resonant cavity. The interaction between the strong induced electric field and the humid air medium is excited in the reference resonant cavity, and the metal grids corresponding to the two cavities, the middle air filling type medium substrate and the capacitor column metalized through holes are utilized, so that the humidity sensor which is compact in structure, free in and out of humid air, strong in up-and-down circulation, capable of gathering water molecules of the humid air in the cavities to fully react with the moisture absorption material, and independent in components and parts, high in sensitivity and high in resolution is obtained.
Description
Technical Field
The invention belongs to the field of sensors, and particularly relates to a microwave passive sensor suitable for detecting air relative humidity.
Background
Humidity is an important index in environmental quality monitoring, and humidity detection has great significance in various laboratories and industrial applications, such as electronic equipment manufacturing, food processing, medical storage, pharmaceutical manufacturing, large-scale equipment operation and the like, which have high requirements on environmental humidity. Therefore, the research and development of the high-performance humidity sensor have high practical value in many fields.
Traditional humidity sensors such as resistive sensors, capacitive sensors and piezoelectric sensors all work at lower frequencies and cannot be directly applied to modern radio frequency sensing detection systems. In order to solve the problem, scientific research personnel have recently proposed the design scheme of the microwave passive humidity sensor. Microwave passive humidity sensors are favored for their low cost, high design flexibility, ease of integration with rf sensing detection systems, and other advantages. However, the microwave passive humidity sensing and monitoring devices reported at present still have the problems of large relative size, low sensing sensitivity, low quality factor and the like, and the practical application range of the devices is severely limited. Frequency division based microwave differential sensors are typically comprised of two sensing devices, one of which serves as the sensing and the other as the reference. And most of the components are combined in the horizontal direction, so that the relative size of the whole structure is large, and the structure is not compact enough.
The applicant has proposed a humidity sensor based on a substrate integrated waveguide re-entry resonant cavity, which has low circulation of a wet air medium, is unable to freely enter and exit, is slow in response and recovery during humidity sensing, and has low resolution because an air through hole is small and the inside of the cavity is a closed structure.
Disclosure of Invention
The invention provides a differential humidity sensor based on a substrate integrated waveguide dual-entrance resonant cavity, which solves the problem that humid air circulates up and down in two resonant cavities, so that the high quality factor characteristic of the resonant cavity is well maintained, and the high-resolution detection of the relative humidity of the air is realized.
The design idea of the invention is to vertically place the sensing and reference resonant cavities, and to adopt a special feed line structure of coplanar waveguide and strip line to longitudinally provide equal power for the two cavities simultaneously. The two resonant cavities are vertically arranged, and the naturally-existing metal walls have good electromagnetic shielding performance, but simultaneously isolate the possibility of up-and-down circulation of humid air.
The technical scheme of the invention is as follows:
a differential humidity sensor based on a substrate integrated waveguide dual-in type resonant cavity comprises two resonant cavities which are overlapped up and down and two feeder lines; the resonant cavity is composed of three medium substrates of an upper layer, a middle layer and a lower layer, and each medium substrate comprises a top metal layer, a middle medium layer and a bottom metal layer.
The resonant cavity of the upper resonant cavity is surrounded by a circle of metalized through holes, the metalized through holes are etched at the same positions of the middle dielectric layers of the three dielectric substrates, and the top metal layer and the bottom metal layer are connected to be equivalent to the metal wall of the resonant cavity.
In the resonant cavity region of the upper resonant cavity, the middle dielectric layer of the upper dielectric substrate is provided with metal through holes distributed in an array manner, a rectangular metal is reserved in the corresponding metal through hole array region on the bottom metal layer, the rest of the rectangular metal is etched away, the rectangular metal and the metalized through holes jointly form a capacitor column structure of the resonant cavity, and the capacitor column is located in the region with the strongest electric field in the cavity. The middle medium substrate is completely dug through from the top metal layer to the bottom metal layer in the resonant cavity region to form an air filling region; and the lower dielectric substrate is etched from the top metal layer to part of the middle dielectric layer in the resonant cavity region to form a groove, and the surface size of the groove is the same as that of the rectangular metal surface to form a sensing functional region. And etching the metalized through hole array around the groove in the middle medium layer of the lower medium substrate to form a metal grid.
The lower resonant cavity and the upper resonant cavity are symmetrical and have the same structure, the capacitor columns in the two resonant cavities are different in size, the cavity with the large size of the capacitor column is a sensing resonant cavity, and the cavity with the small size of the capacitor column is a reference resonant cavity.
The bottom and top metal layers and the metal grid, which are in direct contact between the upper and lower resonant cavities, longitudinally separate the two cavities so that the electromagnetic fields are well confined in the respective cavities.
The upper resonant cavity and the lower resonant cavity realize the free inlet and outlet of the humid air through the metalized through holes of the respective capacitor columns, the metal grating and the air filling type medium substrate.
The feeder lines are arranged on the bottom layer metal and the top layer metal which are directly contacted between the upper resonant cavity and the lower resonant cavity and are symmetrically distributed along the transverse axis.
The beneficial effects of the invention are as follows:
1. the two substrate integrated waveguides are skillfully combined longitudinally, the cavity with the capacitor column with the larger size has a lower frequency point and is used for sensing, and the cavity with the capacitor column with the smaller size has a higher frequency point and is used for reference.
The invention adopts a differential structure form to carry out differential sensing detection on the environmental humidity, and deposits a sensitive material which can absorb water molecules in humid air in a sensing function area of a sensing resonant cavity, namely a groove area, wherein the water molecules are diffused into the sensitive material to cause the change of intrinsic characteristics, for example, the effective dielectric constant of the material is obviously improved, thereby the interaction between an electric field and a moisture absorption material is strongly induced in the cavity of the sensing resonant cavity; the moisture absorption material is not deposited in the sensing function area in the reference resonant cavity, and only the interaction between the strong induced electric field and the humid air medium is excited, so that the sensing sensitivity of the sensor is obviously improved.
2. According to the differential humidity sensor provided by the invention, a humid air medium enters the resonant cavity through the metalized through hole of the reentrant capacitor column, and water molecules of humid air can be better enriched in a sensing function area in the resonant cavity by utilizing a space provided by an air filling area of the intermediate medium substrate, so that a humidity sensing function is realized. Meanwhile, each metal through hole of the metal grating corresponds to each other in the vertical direction one by one, so that the humid air can flow up and down in the two resonant cavities.
It is worth noting that the metal through holes forming the reentrant capacitance column and the metal grating only allow the wet air to enter and exit, while the electromagnetic waves in the two resonant cavities cannot leak from the metallized through holes, the metal grating avoids the mutual coupling between the sensing elements of the two cavities, and the metallized through holes of the reentrant capacitance column avoid the radiation of the electromagnetic waves to the free space, so that the electromagnetic fields are well constrained in the respective cavities. Because the diameters of the metallized through holes are all smaller than lambda/2, the distance between every two adjacent through holes is larger than 60/lambda (lambda is the wavelength corresponding to the working frequency point of the resonant cavity), and the porosity is smaller than fifty percent, the design requirements of the metal grating theory on the diameter, the distance and the porosity of the through holes are met. The resonant cavity can still be considered a closed structure for electromagnetic waves. The characteristic can well maintain the high quality factor characteristic of the resonant cavity, thereby realizing high-resolution detection of the relative humidity of the air.
3. The feeder line of the invention adopts a structure of 'coplanar waveguide + strip line' and a technology that the strip line is connected with the substrate integrated waveguide, thereby not only providing equal power for two longitudinal cavities, but also greatly reducing insertion loss. Compared with the complex feeder line design for two vertically placed microwave differential sensors, the feeder line is designed in an integrated structure, the coplanar waveguide is used for replacing the microstrip line, and the strip line is formed by extending the coplanar waveguide, so that a good feeding effect can be achieved, and the structure can obtain better transmission response.
4. The double-substrate integrated waveguide reentrant resonant cavity structure provided by the invention has resonant frequency points with adjustable height, can realize flexible adjustment of working frequency points by simply adjusting and optimizing key structure parameters in the resonant cavity under the condition of not changing the overall size of the resonant cavity, and has wider application range.
Drawings
FIG. 1 is a schematic cross-sectional view of a differential humidity sensor in accordance with the present invention;
FIG. 2 is an exploded perspective view of the components of the differential humidity sensor of the present invention;
FIG. 3(a) is a schematic front view of a first dielectric substrate of the differential humidity sensor of the present invention;
FIG. 3(b) is a schematic backside view of a first dielectric substrate of the differential humidity sensor of the present invention;
FIG. 4(a) is a schematic front view of second and fifth dielectric substrates of the differential humidity sensor of the present invention;
FIG. 4(b) is a schematic backside view of the second and fifth dielectric substrates of the differential humidity sensor of the present invention;
FIG. 5(a) is a schematic front view of a third dielectric substrate of the differential humidity sensor of the present invention;
FIG. 5(b) is a schematic backside view of a third dielectric substrate of the differential humidity sensor of the present invention;
FIG. 6(a) is a schematic front view of a fourth dielectric substrate of the differential humidity sensor of the present invention;
FIG. 6(b) is a schematic backside view of a fourth dielectric substrate of the differential humidity sensor of the present invention;
FIG. 6(c) is an enlarged view of the feeding portion of the fourth dielectric substrate of the differential humidity sensor proposed by the present invention;
FIG. 6(d) is an enlarged view of the feed line of the differential humidity sensor proposed by the present invention;
FIG. 7(a) is a schematic front view of a sixth dielectric substrate of the differential humidity sensor of the present invention;
FIG. 7(b) is a schematic backside view of a sixth dielectric substrate of the differential humidity sensor of the present invention;
FIG. 8(a) is a graph of the transmission response of a differential humidity sensor according to the present invention under room temperature conditions for sensing the deposition of a sensitive material in a resonant cavity and the non-deposition of a sensitive material;
FIG. 8(b) is a graph of the relationship between the sensing resonant frequency and the relative humidity of the environment after a layer of sensitive material is deposited in the sensing resonant cavity of the differential humidity sensor according to the present invention.
Detailed Description
For better illustration of the design process and purposes, the present invention is further described below with reference to the following examples and the accompanying drawings:
as shown in fig. 1 to fig. 7(a) and fig. 7(b), the substrate integrated waveguide dual-entry resonator-based differential humidity sensor proposed by the present invention comprises two resonators stacked one above the other and two feeder lines (3) of "coplanar waveguide + strip line".
The upper resonant cavity (1) is composed of an upper dielectric substrate (1-1), a middle dielectric substrate (1-2) and a lower dielectric substrate (1-3). The lower resonant cavity (2) is composed of an upper dielectric substrate (2-1), a middle dielectric substrate (2-2) and a lower dielectric substrate (2-3). Each dielectric substrate is provided with a top metal layer, a middle dielectric layer and a bottom metal layer.
The resonant cavity of the upper resonant cavity (1) is surrounded by a circle of metallized through holes (1-1-4), the metallized through holes (1-1-4) are etched at the same positions of the middle dielectric layers of the three dielectric substrates, and the top metal layer and the bottom metal layer are connected to be equivalent to the metal wall of the resonant cavity. And similarly, the resonant cavity of the lower resonant cavity (1) is also surrounded by a circle of metallized through holes, and the metallized through holes are etched at the same positions of the middle dielectric layers of the three dielectric substrates, connect the top metal layer and the bottom metal layer and are equivalent to the metal wall of the resonant cavity. Preferably, the diameter of the metallized through holes is 0.8mm, and the distance between two adjacent through holes is 1.3 mm.
The six dielectric substrates of the two cavities are fixed by 14 screws with the diameter of 1.6mm in an actual structure, and the screws do not influence the work of the resonant cavity.
The materials of the intermediate dielectric layers of the six dielectric substrates are the same, in this embodiment, the material is Rogers 4350, the relative dielectric constant is 3.66, the relative magnetic permeability is 1, and the loss tangent angle is 0.004. Wherein the thicknesses of the intermediate medium substrates (1-2) and (2-2) are the same, and the thickness is 0.578 mm. The other four dielectric substrates have the same thickness, and the thickness is 1.594 mm.
The overall length and width of the six dielectric substrates are the same, and preferably, the length and width are both 60 mm.
The upper-layer dielectric substrate (1-1) of the upper resonant cavity (1) is provided with metal through holes (1-1-1) distributed in an array mode in the central area of the resonant cavity, a rectangular metal (1-1-2) corresponding to the array area of the metal through holes (1-1-1) is reserved in the bottom metal layer and is not etched, and the bottom metal layers of the rest parts in the resonant cavity are etched. The rectangular metal (1-1-2) and the metal through hole (1-1-1) jointly form a capacitance column structure (1-1-3) of the resonant cavity.
Similarly, the lower dielectric substrate (2-3) of the lower resonant cavity (2) is provided with metal through holes (2-3-1) distributed in an array manner in the central area of the resonant cavity, a rectangular metal (2-3-2) corresponding to the array area of the metal through holes (2-3-1) is left in the top metal layer and is not etched, and the bottom metal layers of the rest parts in the resonant cavity are etched. The rectangular metal (2-3-2) and the metalized through hole (2-3-1) jointly form a capacitor column structure (2-3-3) of the resonant cavity.
Preferably, the diameter of the metal through holes (1-1-1) and (2-3-1) is 2mm, and the distance between two adjacent through holes is 3.35 mm. The length and the width of the rectangular metal (1-1-2) of the upper resonant cavity (1) are both 17mm, the length and the width of the rectangular metal (2-3-2) of the lower resonant cavity (2) are both 14mm, the sizes of the capacitor columns in the two resonant cavities are different, the cavity with the large size of the capacitor column is a sensing resonant cavity, and the cavity with the small size of the capacitor column is a reference resonant cavity.
Referring to fig. 4(a) and 4(b), in the two resonant cavities, the intermediate dielectric substrates (1-2) and (2-2) have the same structure, and are completely dug through from the top metal layer to the bottom metal layer in the resonant cavity region to form an air filling type region, which aims to better enrich water molecules in humid air in the sensing function region in the resonant cavity, thereby realizing the humidity sensing function. Preferably, the hollowed-out air-filled region has a length and width of 34 mm.
The middle dielectric layers of the lower dielectric substrate (1-3) of the upper resonant cavity (1) and the upper dielectric substrate (2-1) of the lower resonant cavity (2) are etched with rectangular grooves (1-3-1) and (2-1-1), and the purpose is to form a sensing function area. The length and the width of a rectangular groove (1-3-1) etched by a middle medium layer of a lower medium substrate (1-3) of the upper resonant cavity (1) are both 17mm, and the depth of the groove is 0.5 mm; the length and the width of a rectangular groove (2-1-1) etched in the middle medium layer of the upper medium substrate (2-1) of the lower resonant cavity (2) are both 14mm, and the depth of the groove is 0.5 mm.
A plurality of metalized through holes are etched in the middle medium layer of the lower medium substrate (1-3) and the upper medium substrate (2-1) around the rectangular groove (1-3-1) and the rectangular groove (2-1-1) in an array mode to form a metal grid, the metal grid (1-3-2) is connected with the bottom metal of the lower medium substrate (1-3) of the upper resonant cavity (1), the metal grid (2-1-2) is connected with the top metal of the upper medium substrate (2-1) of the lower resonant cavity (2), and the metalized through holes are in one-to-one correspondence in the vertical direction, so that humid air can fully circulate in the two resonant cavities, electromagnetic waves are shielded, and electromagnetic fields are well constrained in the cavities. The metal grids corresponding to the two cavities, the air filling area of the intermediate medium substrate and the metalized through holes of the capacitor columns are utilized to realize free inlet and outlet of humid air, so that the upper and lower circulations are strong, and water molecules of the humid air can be enriched in the cavities to fully react with the moisture absorption material.
Based on the metal grid shielding theory, the design requirements on the diameter of the metalized through holes, the space between adjacent holes and the porosity are met, and preferably, the diameter of the metalized through holes is designed to be 1.2mm, and the space between adjacent through holes is designed to be 1.7 mm. The wavelength corresponding to the working frequency point of the sensor is 47.89mm, and the diameter of the through hole is designed to meet the requirement of 1.2mm<Lambda/2 is 23.94mm, and the distance between adjacent holes is satisfied
The porosity is 19.56%<50 percent, thereby achieving the purpose of shielding electromagnetic waves.
Referring to fig. 5 b and fig. 6 a, the differential humidity sensor is composed of a feeding line structure (2-1-3) of the lower resonant cavity (2) and a feeding line structure (1-3-4) of the upper resonant cavity (1) which together form a coplanar waveguide + strip line feeding line (3).
Referring to fig. 6 c, the feeder structure (2-1-3) of the lower resonant cavity (2) is composed of three parts, the coplanar waveguide feeder of the first part (a) is of a rhombus gradient structure, the total length is 6.2mm, the width of the feeder is 3mm, the width of the slot on two sides of the feeder is 0.35mm, the width of the rhombus feed port is 0.8mm, and the width of the feed port gradually increases from the feed port to the center of the cavity. Gradually change to 3mm wide after the length of 3.5mm, pause gradual change this moment, after 1.3mm, gradually change from 3mm wide to 1.5mm wide again, this time gradual change length 1.4 mm.
The second part (B) of the feeder line structure (2-1-3) of the lower resonant cavity (2) is a conical gradual change structure and is formed by extending the first part (A) of the coplanar waveguide feeder line. The total length is 8.6mm, and feeder width 1.5mm, and the gap width of feeder both sides is 0.35mm, diminishes after 7.6 mm's length gradually, by 1.5mm wide gradual change 0.8mm wide, this time gradual change length 2 mm.
And the third part (C) of the feeder line structure (2-1-3) of the lower resonant cavity (2) is a nonmetal through hole with the diameter of 2mm, which is symmetrically distributed along the horizontal axis, and the hole interval is 9.53mm, and is used for connecting a welding-free terminal connector.
Referring to fig. 6 d, the upper resonant cavity (1) is etched with the same feed line structure (1-3-4) as the second portion (B) of the feed line structure (2-1-3) at the position where the bottom metal of the lower dielectric substrate (1-3) is in contact with the top metal of the upper dielectric substrate (2-1). The second part (B) of the feed line structure (2-1-3) and the feed line structure (1-3-4) together form a 'strip line' structure.
The diamond-shaped and conical gradual change structures are used for meeting the impedance matching requirement of the input port and realizing simultaneous excitation of two resonant cavities, thereby realizing good transmission response.
In order to use the welding-free terminal connector, rectangular gaps (1-3-5) are etched in the positions, corresponding to the first part () coplanar waveguide feeder line of the feeder line structure (2-1-3), of the upper dielectric substrate (1-1), the middle dielectric substrate (1-2), the lower dielectric substrate (1-3) and the middle dielectric substrate (2-2) and the lower dielectric substrate (2-3) of the upper resonant cavity (1) and the lower resonant cavity (2) of the differential humidity sensor from the top metal to the bottom metal. Preferably, the etching length is 15mm and the width is 6.2 mm.
Fig. 8(a) is a transmission response curve of the differential humidity sensor proposed by the present invention under room temperature conditions between the deposition and non-deposition of the sensitive material in the sensing functional region (1-3-1) of the sensing resonant cavity (1). At room temperature, the relative humidity in the room was 78.2% as measured by a temperature and humidity meter. The differential humidity sensor without the deposited sensitive material excites strong resonance at 3.787GHz and 3.884GHz respectively, a layer of hygroscopic sensitive material is deposited in a sensing area (1-3-1) of the sensing resonant cavity (1), water molecules diffuse into the sensitive material to improve the effective dielectric constant of the material, and the interaction between a strong induced electric field and the hygroscopic material is excited to change the resonant frequency of the sensing resonant cavity to 3.761 GHz. And meanwhile, the resonance frequency point positioned higher is basically unchanged because the existing environmental factors are not changed. Referring to fig. 8(b), after a layer of sensitive material is deposited on the sensing resonant cavity, the sensor under different relative humidity environments measures the functional relationship between the sensing resonant frequency and the relative humidity of the environment, when the relative humidity is increased from 41.9% to 97.3%, the resonant frequency of the sensing resonant cavity (1) is reduced from 3.77075GHz to 3.75875GHz, and the offset of the resonant frequency is 12 MHz. The sensor is shown to have high sensitivity characteristics.
The invention adopts a differential structure form to carry out differential sensing detection on the environmental humidity, and deposits a sensitive material (1-3-3) capable of adsorbing water molecules in humid air in a sensing functional area, namely a groove area, of a sensing resonant cavity, and refers to a figure (1) and a figure (5) a. When the sensor is exposed in a humidity environment, a humid air medium enters the resonant cavity through metallized through holes (1-1-3) and (2-3-3) of capacitor columns of an upper medium substrate of an upper resonant cavity (1) and a lower medium substrate of a lower resonant cavity (2) and is enriched in preset sensing areas (1-3-1) and (2-1-1), the diffusion of water molecules into a sensitive material can cause the change of the intrinsic characteristics of the sensitive material, for example, the effective dielectric constant of the material can be obviously improved, so that the interaction between an electric field and a moisture absorption material is strongly induced in the cavity of the sensing resonant cavity, the resonance frequency point of the sensing resonant cavity is shifted, and the shift amount is determined by the degree of the sensitive material absorbing the water molecules; the sensing function area in the reference resonant cavity is not deposited with the moisture absorption material, and only the interaction between the strong induced electric field and the humid air medium is excited, so that the resonant frequency point of the resonant cavity is shifted, and the shift amount is determined by the relative humidity of the air. The bottom layer metal, the top layer metal and the metal grating which are directly contacted with each other between the two resonant cavities longitudinally isolate the two cavities, and the metalized through holes of the reentrant capacitor columns avoid electromagnetic wave radiation to free space, so that the electromagnetic field is well bound in the respective cavities.
The sensor is formed by combining six dielectric substrates, two resonant cavities which are superposed up and down, and a special feed design is adopted, so that the structure is very compact. The whole differential humidity sensor takes a resonant cavity as sensing and deposits hygroscopic material in a sensing function area; the other resonant cavity is not deposited with moisture absorption material in the sensing function area as reference. The metal grating formed by the design of the metalized through holes in the adjacent medium substrates of the two cavities, the middle air filling type medium substrate and the metalized through holes of the reentrant type capacitor columns are utilized, so that the functions of free entry and exit of humid air, strong up-down circulation and full reaction of water molecules of the humid air with a moisture absorption material in the cavities can be realized. Meanwhile, good electromagnetic shielding is arranged between the two cavities, so that high-sensitivity and high-resolution detection of the relative humidity of air is realized, and urgent requirements of various subject fields on high-performance air humidity sensors are met.
The present invention is not limited to the above-described embodiments, and various modifications and variations of the invention are intended to be included within the scope of the claims and the equivalent technology of the present invention if they do not depart from the spirit and scope of the present invention.
Claims (6)
1. A differential humidity sensor based on a substrate integrated waveguide dual-entrance resonant cavity is characterized in that: comprises two resonance cavities which are superposed up and down and two feeder lines (3); the resonant cavity is composed of three medium substrates, namely an upper layer medium substrate, a middle layer medium substrate and a lower layer medium substrate, wherein each medium substrate comprises a top metal layer, a middle medium layer and a bottom metal layer;
the resonant cavity of the upper resonant cavity (1) is surrounded by a circle of metallized through holes (1-1-4), the metallized through holes (1-1-4) are etched at the same positions of the middle dielectric layers of the three dielectric substrates, and the top metal layer and the bottom metal layer are connected and are equivalent to the metal wall of the resonant cavity;
in a resonant cavity region of the upper resonant cavity (1), a middle dielectric layer of an upper dielectric substrate (1-1) is provided with metal through holes (1-1-1) distributed in an array manner, a rectangular metal (1-1-2) is reserved on a bottom metal layer in the array region corresponding to the metal through holes (1-1-1), the rest of the rectangular metal is etched, the rectangular metal (1-1-2) and the metal through holes (1-1-1) jointly form a capacitor column structure (1-1-3) of the resonant cavity, and the position of the capacitor column structure is a region with the strongest electric field in the cavity; the middle medium substrate (1-2) is completely dug through from the top metal layer to the bottom metal layer in the resonant cavity region to form an air filling region; the lower dielectric substrate (1-3) is etched from the top metal to part of the middle dielectric layer in the resonant cavity region to form a groove (1-3-1), the surface size of the groove is the same as that of the rectangular metal (1-1-2), and a sensing function region is formed; etching a metalized through hole array around the groove in the middle dielectric layer of the lower dielectric substrate (1-3) to form a metal grid (1-3-2);
the lower resonant cavity (2) and the upper resonant cavity (1) are symmetrical and have the same structure, the sizes of the capacitor columns in the two resonant cavities are different, the cavity with the large size of the capacitor column is a sensing resonant cavity, and the cavity with the small size of the capacitor column is a reference resonant cavity;
the bottom layer metal and the top layer metal which are directly contacted between the upper resonant cavity (1) and the lower resonant cavity (2) and the metal grating longitudinally isolate the two cavities, so that electromagnetic fields are well bound in the respective cavities;
the upper resonant cavity (1) and the lower resonant cavity (2) realize the free inlet and outlet of humid air through the metalized through holes of the respective capacitor columns, the metal grids and the air filling type area;
the feeder lines (3) are arranged on the bottom layer metal and the top layer metal which are in direct contact between the upper resonant cavity body (1) and the lower resonant cavity body (2) and are symmetrically distributed along the transverse axis.
2. The differential humidity sensor of claim 1, wherein: go up resonant cavity (1) and each metal through-hole that forms the metal grating of resonant cavity (2) down on the vertical direction one-to-one for moist air can be abundant circulate in two resonant cavity, the electromagnetic wave of shielding simultaneously, makes the fine constraint of electromagnetic field in cavity separately.
3. The differential humidity sensor of claim 2, wherein: the diameter of the metalized through holes for forming the metal grid is smaller than that of the metalized through holes
The distance between adjacent through holes is larger than
，
The porosity is less than fifty percent of the wavelength corresponding to the working frequency point of the resonant cavity.
4. A microwave differential sensor according to claims 1, 2, characterized in that: the feeder line (3) is formed by a feeder line structure (1-3-4) on the upper resonant cavity (1) and a feeder line structure (2-1-3) on the lower resonant cavity (2) together, namely a coplanar waveguide and a strip line.
5. The differential humidity sensor of claim 4, wherein: the feed line structure (2-1-3) consists of three parts, wherein the coplanar waveguide feed line of the first part (A) is of a rhombic gradually-changed structure, the total length is 6.2mm, the width of the feed line is 3mm, the width of gaps on two sides of the feed line is 0.35mm, the width of a rhombic feed-in port is 0.8mm, and the feed-in port gradually increases from the feed-in port to the center of the cavity;
gradually changing the length of the paper to 3mm width after the paper passes through 3.5mm, pausing the gradual change, gradually changing the width of the paper from 3mm to 1.5mm after the paper passes through 1.3mm, and gradually changing the length of the paper to 1.4 mm;
the second part (B) of the feed line structure (2-1-3) is a conical gradual change structure and is formed by extending the coplanar waveguide feed line of the first part (A);
the total length is 8.6mm, the width of the feeder line is 1.5mm, the width of the gap on the two sides of the feeder line is 0.35mm, the gap gradually becomes smaller after the length of 7.6mm, the width gradually changes from 1.5mm to 0.8mm, and the length gradually changes to 2 mm;
the third part (C) of the feed line structure (2-1-3) is a non-metalized through hole with the diameter of 2mm, which is symmetrically distributed along the transverse axis, and the hole spacing is 9.53mm, and is used for connecting a welding-free terminal connector;
the position of the feed line structure (2-1-3) corresponds to the position of the second part of the feed line structure (2-1-3), the structure is the same, and the second part (B) of the feed line structure (2-1-3) and the feed line structure (1-3-4) jointly form a strip line structure.
6. A differential sensor as claimed in claim 1, 2 or 3 wherein: the intermediate medium layer materials of all the medium substrates are Rogers 4350, the relative dielectric constant is 3.66, the relative magnetic permeability is 1, and the loss tangent angle is 0.004.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110876949.8A CN113740353B (en) | 2021-07-31 | 2021-07-31 | Differential humidity sensor based on substrate integrated waveguide dual-entry resonant cavity |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110876949.8A CN113740353B (en) | 2021-07-31 | 2021-07-31 | Differential humidity sensor based on substrate integrated waveguide dual-entry resonant cavity |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113740353A true CN113740353A (en) | 2021-12-03 |
| CN113740353B CN113740353B (en) | 2022-10-14 |
Family
ID=78729760
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110876949.8A Active CN113740353B (en) | 2021-07-31 | 2021-07-31 | Differential humidity sensor based on substrate integrated waveguide dual-entry resonant cavity |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113740353B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114441558A (en) * | 2022-01-30 | 2022-05-06 | 西南大学 | High-resolution radio frequency tag sensor based on microwave negative resistance circuit compensation technology |
Citations (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030137313A1 (en) * | 2001-01-20 | 2003-07-24 | Bert Jannsen | Resonant microwave sensor |
| US20110248890A1 (en) * | 2010-04-13 | 2011-10-13 | Samsung Electro-Mechanics Co ., Ltd. | Dielectric resonator antenna embedded in multilayer substrate for enhancing bandwidth |
| US20130088396A1 (en) * | 2011-10-05 | 2013-04-11 | Samsung Electro-Mechanics Co., Ltd. | Bandwidth adjustable dielectric resonant antenna |
| US20130127669A1 (en) * | 2011-11-18 | 2013-05-23 | Samsung Electro-Mechanics Co., Ltd. | Dielectric cavity antenna |
| US20150168314A1 (en) * | 2013-11-11 | 2015-06-18 | 3R Valo, société en commandite | Microwave resonator sensor and associated methods of sensing |
| US20160036110A1 (en) * | 2013-04-15 | 2016-02-04 | Huawei Technologies Co., Ltd. | Waveguide Filter |
| CN106410336A (en) * | 2016-09-29 | 2017-02-15 | 上海航天测控通信研究所 | Stacked type three-order substrate integrated waveguide filter |
| CN108987924A (en) * | 2018-07-16 | 2018-12-11 | 西安电子科技大学 | Substrate integration wave-guide bimodulus filter antenna with more radiation zeros |
| CN109462000A (en) * | 2018-11-06 | 2019-03-12 | 上海航天计算机技术研究所 | A kind of three rank model filters power splitter of multi layer substrate integrated waveguide |
| CN110336100A (en) * | 2019-06-19 | 2019-10-15 | 华中科技大学 | A kind of air filling SIW double-passband filter and its optimization method |
| CN110346414A (en) * | 2019-07-15 | 2019-10-18 | 西南大学 | A kind of humidity sensor based on substrate integrated waveguide reentrant cavity |
| US20200287277A1 (en) * | 2017-07-18 | 2020-09-10 | Southeast University | Low-profile broadband circularly-polarized array antenna using stacked traveling wave antenna elements |
| CN112684259A (en) * | 2020-12-04 | 2021-04-20 | 西南大学 | Reentrant cavity sensor for measuring dielectric constant and magnetic conductivity of magnetic medium material |
| CN112798870A (en) * | 2020-12-09 | 2021-05-14 | 西南大学 | Microwave differential sensor based on substrate integrated waveguide reentry type resonant cavity and microfluidic technology |
| CN112986692A (en) * | 2021-02-03 | 2021-06-18 | 四川大学 | Complex dielectric constant sensor based on medium integrated suspension line, measuring system and measuring method |
-
2021
- 2021-07-31 CN CN202110876949.8A patent/CN113740353B/en active Active
Patent Citations (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030137313A1 (en) * | 2001-01-20 | 2003-07-24 | Bert Jannsen | Resonant microwave sensor |
| US20110248890A1 (en) * | 2010-04-13 | 2011-10-13 | Samsung Electro-Mechanics Co ., Ltd. | Dielectric resonator antenna embedded in multilayer substrate for enhancing bandwidth |
| US20130088396A1 (en) * | 2011-10-05 | 2013-04-11 | Samsung Electro-Mechanics Co., Ltd. | Bandwidth adjustable dielectric resonant antenna |
| US20130127669A1 (en) * | 2011-11-18 | 2013-05-23 | Samsung Electro-Mechanics Co., Ltd. | Dielectric cavity antenna |
| US20160036110A1 (en) * | 2013-04-15 | 2016-02-04 | Huawei Technologies Co., Ltd. | Waveguide Filter |
| US20150168314A1 (en) * | 2013-11-11 | 2015-06-18 | 3R Valo, société en commandite | Microwave resonator sensor and associated methods of sensing |
| CN106410336A (en) * | 2016-09-29 | 2017-02-15 | 上海航天测控通信研究所 | Stacked type three-order substrate integrated waveguide filter |
| US20200287277A1 (en) * | 2017-07-18 | 2020-09-10 | Southeast University | Low-profile broadband circularly-polarized array antenna using stacked traveling wave antenna elements |
| CN108987924A (en) * | 2018-07-16 | 2018-12-11 | 西安电子科技大学 | Substrate integration wave-guide bimodulus filter antenna with more radiation zeros |
| CN109462000A (en) * | 2018-11-06 | 2019-03-12 | 上海航天计算机技术研究所 | A kind of three rank model filters power splitter of multi layer substrate integrated waveguide |
| CN110336100A (en) * | 2019-06-19 | 2019-10-15 | 华中科技大学 | A kind of air filling SIW double-passband filter and its optimization method |
| CN110346414A (en) * | 2019-07-15 | 2019-10-18 | 西南大学 | A kind of humidity sensor based on substrate integrated waveguide reentrant cavity |
| CN112684259A (en) * | 2020-12-04 | 2021-04-20 | 西南大学 | Reentrant cavity sensor for measuring dielectric constant and magnetic conductivity of magnetic medium material |
| CN112798870A (en) * | 2020-12-09 | 2021-05-14 | 西南大学 | Microwave differential sensor based on substrate integrated waveguide reentry type resonant cavity and microfluidic technology |
| CN112986692A (en) * | 2021-02-03 | 2021-06-18 | 四川大学 | Complex dielectric constant sensor based on medium integrated suspension line, measuring system and measuring method |
Non-Patent Citations (8)
| Title |
|---|
| ANH TU HO, MAJID NDOYE: "Miniaturized Humidity Sensor based on a partially Air-filled Slow-Wave SIW Resonator", 《PROCEEDINGS OF THE 48TH EUROPEAN MICROWAVE CONFERENCE》, 30 September 2018 (2018-09-30) * |
| SEYED EHSAN MOHSIR，MOJTABA JOODAKI: "Design and Implementation of SIW Cavity Oscillators for Humidity Sensing Applications", 《2020 28TH IRANIAN CONFERENCE ON ELECTRICAL ENGINEERING (ICEE)》, 31 December 2020 (2020-12-31) * |
| YUHAN XIANG, JIE HUANG: "A_Folded_Substrate_Integrated_Waveguide_Re-Entrant_Cavity_for_Full_Characterization_of_Magneto-Dielectric_Powder_Materials", 《IEEE SENSORS JOURNAL》, vol. 21, no. 9, 1 May 2021 (2021-05-01) * |
| 刘勇，陈昌明，高睿: "基于基片集成波导的湿度传感器设计*", 《传感器与微系统》, vol. 37, no. 2, 31 December 2018 (2018-12-31) * |
| 刘勇等: "基于基片集成波导的湿度传感器设计", 《传感器与微系统》, no. 02, 5 February 2018 (2018-02-05) * |
| 张勐等: "光学谐振腔式湿度传感器的研究进展", 《传感器与微系统》 * |
| 张勐等: "光学谐振腔式湿度传感器的研究进展", 《传感器与微系统》, no. 11, 30 October 2018 (2018-10-30) * |
| 张淑娥等: "微波谐振腔湿度测量同轴环耦合设计与实现", 《国外电子元器件》, no. 11, 5 November 2008 (2008-11-05) * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114441558A (en) * | 2022-01-30 | 2022-05-06 | 西南大学 | High-resolution radio frequency tag sensor based on microwave negative resistance circuit compensation technology |
| CN114441558B (en) * | 2022-01-30 | 2024-03-15 | 西南大学 | High-resolution radio frequency tag sensor based on microwave negative resistance circuit compensation technology |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113740353B (en) | 2022-10-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109239465B (en) | Microwave sensor based on substrate integrated waveguide and microfluidic technology | |
| CN110346414B (en) | Humidity sensor based on substrate integrated waveguide reentry type resonant cavity | |
| CN113740353B (en) | Differential humidity sensor based on substrate integrated waveguide dual-entry resonant cavity | |
| CN112798870B (en) | Microwave differential sensor based on substrate integrated waveguide reentry type resonant cavity and microfluidic technology | |
| CN109781748A (en) | Microwave remote sensor based on differential type substrate integrated waveguide reentrant cavity and microflow control technique | |
| CN112684259B (en) | Reentrant cavity sensor for measuring dielectric constant and magnetic conductivity of magnetic medium material | |
| US20110256763A1 (en) | Mitigation of crosstalk resonances in interconnects | |
| US4434666A (en) | Electromagnetic flowmeters and methods for measuring flow | |
| CN111257349B (en) | Microwave sensor based on substrate integrated waveguide and gap capacitance resonance technology | |
| CN106571508A (en) | Fourth-mode and eighth-mode substrate integrated waveguide-based balanced band-pass filter | |
| CN113049882B (en) | Substrate integrated waveguide reentrant resonant cavity microwave sensor with annular gap | |
| CN207753150U (en) | embedded directional coupler | |
| US20150054713A1 (en) | Electromagnetic band gap element, electronic circuit,and conductor structure | |
| CN114545094A (en) | High-sensitivity microwave sensor for measuring dielectric constant of material | |
| CN209460165U (en) | A kind of microwave remote sensor | |
| CN110988487B (en) | Microwave microfluid sensor based on T-shaped feeder line excitation complementary open-loop resonator | |
| CN105703042B (en) | S type minimizes the broadband transparent structure that frequency-selective surfaces are constituted | |
| CN111066198B (en) | Ceramic dielectric filter | |
| CN115541669A (en) | Humidity sensor based on substrate integrated waveguide re-entry resonant cavity and six-port interference network | |
| CN114441558B (en) | High-resolution radio frequency tag sensor based on microwave negative resistance circuit compensation technology | |
| CN1937307A (en) | High performance frequency selective surface based on integrated waveguide multi-cavity cascade | |
| CN114497960B (en) | Double-frequency point radio frequency tag sensor based on substrate integrated waveguide folding technology | |
| CN107546448B (en) | A kind of inclined-plane absorption based on SIW transmission line is array-supported | |
| CN108387784B (en) | Magnetic film inductive sensor | |
| Riblet | An accurate approximation of the impedance of a circular cylinder concentric with an external square tube |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |