A multi-ring coupled IDE based substrate integrated waveguide sensor

Abstract

The application discloses a substrate integrated waveguide sensor based on a multi-ring coupling type IDE and relates to the technical field of detection. The substrate integrated waveguide sensor comprises a sensor module, a first SMA port and a second SMA port. The sensor module comprises, from top to bottom, a horizontal radiation patch, a substrate integrated waveguide and a metal grounding plate. The horizontal radiation patch comprises a patch body, a first power supply end, a second power supply end and an interdigital electrode etched on the upper surface of the patch body. The interdigital electrode comprises a capacitor, a first conductive electrode, a second conductive electrode, a first electrode unit, a second electrode unit, a third electrode unit and a fourth electrode unit. The first electrode unit, the second electrode unit, the third electrode unit and the fourth electrode unit each comprise a first rectangular electrode, a second rectangular electrode and a special-shaped electrode. The application can realize accurate detection of slight changes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of detection, and particularly relates to a substrate integrated waveguide sensor based on a multi-ring coupling type IDE. BACKGROUND

[0002] Microwave sensors are widely used in various industries due to their simple structure, strong adaptability, high precision, wide coverage and other advantages.

[0003] At present, the research on high-sensitivity microwave sensors applicable to reagent detection is not mature. For example, patent CN118329934A discloses a liquid concentration self-sustaining measurement microwave active sensor, patent CN117630497A discloses a double-sided attached liquid dielectric constant detection microwave sensor, and patent CN117517349A discloses a microwave antenna-based liquid sensor, an edible oil detection system and a method. However, the structures of the above-mentioned schemes are relatively complex and the sensitivity is relatively low, and it is difficult to meet the needs of traditional Chinese medicine decoction detection and other scenes requiring high sensitivity. Such detection often relies on accurate capture of subtle changes.

[0004] Therefore, it is of great significance to design a microwave sensor with a simple structure and high sensitivity. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a substrate integrated waveguide sensor based on a multi-ring coupling type IDE, which can realize accurate detection of slight changes.

[0006] To address the aforementioned technical problems, this invention provides a substrate integrated waveguide sensor based on a multi-ring coupled IDE, comprising a sensor module, a first SMA port, and a second SMA port. The first SMA port and the second SMA port are symmetrically disposed at both ends of the sensor module. The sensor module includes a horizontal radiating patch, a substrate integrated waveguide, and a metal ground plane arranged sequentially from top to bottom. The horizontal radiating patch includes a patch body, a first power supply terminal, a second power supply terminal, and interdigitated electrodes etched on the upper surface of the patch body. The first power supply terminal is disposed at one end of the patch body and connected to the first SMA port, and the second power supply terminal is disposed at the other end of the patch body and connected to the second SMA port. The interdigitated electrodes... The electrode includes a capacitor, a first conductive electrode, a second conductive electrode, a first electrode unit, a second electrode unit, a third electrode unit, and a fourth electrode unit. A transmission port of the first and fourth electrode units is connected to one end of the capacitor via the first conductive electrode. A transmission port of the second and third electrode units is connected to the other end of the capacitor via the second conductive electrode. The other transmission ports of the first and second electrode units are connected, and the other transmission ports of the third and fourth electrode units are also connected. Each of the first, second, third, and fourth electrode units includes a first rectangular electrode, a second rectangular electrode, and an irregularly shaped electrode. The irregularly shaped electrode includes a first "..." connected in sequence. "Type electrode", "Type electrode, first" "Type electrode", "Type electrode, second" "Type electrode and second" "-shaped electrode, the first rectangular electrode is disposed on the first " The recessed area of ​​the "-shaped electrode, the second rectangular electrode is disposed in the second " The recessed area of ​​the "-shaped electrode".

[0007] As an improvement to the above solution, the first electrode unit and the second electrode unit are symmetrically arranged in the width direction of the horizontal radiating patch, the third electrode unit and the fourth electrode unit are symmetrically arranged in the width direction of the horizontal radiating patch, the first electrode unit and the fourth electrode unit are symmetrically arranged in the length direction of the horizontal radiating patch, and the second electrode unit and the third electrode unit are symmetrically arranged in the length direction of the horizontal radiating patch.

[0008] As an improvement to the above solution, the first " One end of the "type electrode" is connected to the " The first electrode is composed of a "-shaped" electrode. The other end of the "type electrode" is connected to the " The second electrode is formed by the second ''-'' shaped electrode, one end of the second ''-'' shaped electrode and the third ''-'' shaped electrode, and the other end of the second ''-'' shaped electrode and the fourth ''-'' shaped electrode.

[0009] As an improvement of the above-mentioned scheme, the second ''-'' shaped electrode is connected with the third ''-'' shaped electrode at one end, and the fourth ''-'' shaped electrode at the other end. As an improvement of the above-mentioned scheme, the second ''-'' shaped electrode is connected with the third ''-'' shaped electrode at one end, and the fourth ''-'' shaped electrode at the other end. As an improvement of the above-mentioned scheme, the second ''-'' shaped electrode is connected with the third ''-'' shaped electrode at one end, and the fourth ''-'' shaped electrode at the other end.

[0010] As an improvement of the above-mentioned scheme, the sensor module has an elliptical structure.

[0011] As an improvement of the above-mentioned scheme, the sensor module has an elliptical structure.

[0012] As an improvement of the above-mentioned scheme, the sensor module has an elliptical structure.

[0013] As an improvement of the above-mentioned scheme, the sensor module has an elliptical structure.

[0014] As an improvement of the above-mentioned scheme, the sensor module has an elliptical structure.

[0015] As an improvement of the above-mentioned scheme, the sensor module has an elliptical structure.

[0016] The substrate integrated waveguide sensor based on the multi-ring coupling IDE is not only suitable for detecting traditional Chinese medicine reagents, but also can be widely applied in heavy metal detection and other fields.

[0017] The substrate integrated waveguide sensor based on the multi-ring coupling IDE can effectively prolong the current path of the horizontal radiation patch center resonant structure by introducing the annular symmetric interdigital electrode, and maximize the concentration and restraint of electromagnetic energy in the center area of the horizontal radiation patch, so that more electromagnetic energy is stored in the structure to realize more accurate detection of small changes.

[0018] ​​Further, the present application adds metal baffles to concentrate energy on the center of the sensor, thereby generating a strong electric field above the sensor module, enabling the sensor module to store a large amount of electromagnetic energy, further improving detection performance, and the overall structure is simple and reasonable in design. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a first embodiment of the substrate integrated waveguide sensor based on the multi-ring coupled IDE of the present application;

[0020] Figure 2 is a front view of the first embodiment of the substrate integrated waveguide sensor based on the multi-ring coupled IDE of the present application;

[0021] Figure 3 is Figure 2 a front view of the interdigital electrode;

[0022] Figure 4 is a side view of the second embodiment of the substrate integrated waveguide sensor based on the multi-ring coupled IDE of the present application;

[0023] Figure 5 is a front view of the second embodiment of the substrate integrated waveguide sensor based on the multi-ring coupled IDE of the present application;

[0024] Figure 6 is Figure 5 a front view of the interdigital electrode;

[0025] Figure 7 is another front view of the second embodiment of the substrate integrated waveguide sensor based on the multi-ring coupled IDE of the present application;

[0026] Figure 8 is an electric field intensity distribution diagram of the substrate integrated waveguide sensor based on the multi-ring coupled IDE of the present application at 5.63 GHz;

[0027] Figure 9 is a S 21 resonance point frequency offset result diagram under different dielectric constants. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings. It is hereby declared that the up, down, left, right, front, back, inside and outside orientation words appearing or about to appear in the present application are based on the drawings of the present application, and are not specific limitations on the present application.

[0029] Referring to Figure 1 and Figure 2 , Figure 1 and Figure 2The first embodiment of the present invention based on an integrated waveguide IDE (interdigitated electrons) sensor is shown, which includes a sensor module, a first SMA port 1 and a second SMA port 2, the first SMA port 1 and the second SMA port 2 being symmetrically disposed at both ends of the sensor module. The sensor module includes a horizontal radiating patch 3, a substrate integrated waveguide 4 and a metal ground plane 5 arranged sequentially from top to bottom.

[0030] In this embodiment, the substrate integrated waveguide 4 is a Rogers RO4350 rectangular substrate integrated waveguide, and the metal ground plane 5 is a rectangular metal ground plane, with the rectangular substrate integrated waveguide and the rectangular metal ground plane being the same size. The horizontal radiating patch 3 is placed on the upper layer of the substrate integrated waveguide 4, and the metal ground plane 5 is placed on the lower layer of the substrate integrated waveguide 4. The substrate integrated waveguide 4 is sampled on the left and right sides through two SMA ports (first SMA port 1 and second SMA port 2) to excite the entire sensor module in a dual-port feeding manner, so that a strong electric field is formed at the center of the horizontal radiating patch 3.

[0031] like Figure 1 and Figure 2 As shown, the horizontal radiation patch 3 includes a patch body, a first power supply terminal 31, a second power supply terminal 32, and interdigitated electrodes 33 etched on the upper surface of the patch body. The first power supply terminal 31 is located at one end of the patch body and connected to the first SMA port 1, and the second power supply terminal 32 is located at the other end of the patch body and connected to the second SMA port 2.

[0032] like Figure 2 and Figure 3 As shown, the interdigitated electrode 33 includes a capacitor 331, a first conductive electrode 332, a second conductive electrode 333, a first electrode unit 33a, a second electrode unit 33b, a third electrode unit 33c, and a fourth electrode unit 33d. One transmission port of the first electrode unit 33a and the fourth electrode unit 33d is connected to one end of the capacitor 331 through the first conductive electrode 332. One transmission port of the second electrode unit 33b and the third electrode unit 33c is connected to the other end of the capacitor 331 through the second conductive electrode 333. The other transmission ports of the first electrode unit 33a and the second electrode unit 33b are connected, and the other transmission ports of the third electrode unit 33c and the fourth electrode unit 33d are connected, thereby forming a ring resonant structure.

[0033] The first electrode unit 33a, the second electrode unit 33b, the third electrode unit 33c, and the fourth electrode unit 33d each include a first rectangular electrode 334, a second rectangular electrode 335, and an irregularly shaped electrode 336. The irregularly shaped electrode 336 includes a first rectangular electrode 334 connected in sequence to the first rectangular electrode 335. "Type electrode", "Type electrode, first" "Type electrode", ” type electrode, and the second “ ” type electrode and the second “ ” type electrode, the first rectangular electrode 334 is arranged in the recessed area of the first “ ” type electrode, and the second rectangular electrode 335 is arranged in the recessed area of the second “ ” type electrode.

[0034] That is, the special-shaped electrodes 336 in the embodiment are staggered with the rectangular electrodes (the first rectangular electrode 334 and the second rectangular electrode 335), and a plurality of capacitive gaps are formed between adjacent electrodes, thereby generating a larger equivalent capacitance and enhancing the local electric field.

[0035] Therefore, the embodiment can effectively prolong the current path of the center resonant structure of the horizontal radiation patch 3, and maximize the concentration and restraint of electromagnetic energy in the central region of the horizontal radiation patch 3, so that the structure stores more electromagnetic energy to achieve more accurate detection of small changes.

[0036] Further, in the embodiment, the first electrode unit 33a and the second electrode unit 33b are symmetrically arranged in the width direction of the horizontal radiation patch 3, the third electrode unit 33c and the fourth electrode unit 33d are symmetrically arranged in the width direction of the horizontal radiation patch 3, the first electrode unit 33a and the fourth electrode unit 33d are symmetrically arranged in the length direction of the horizontal radiation patch 3, and the second electrode unit 33b and the third electrode unit 33c are symmetrically arranged in the length direction of the horizontal radiation patch 3.

[0037] Therefore, the embodiment symmetrizes the resonant structure on the horizontal radiation patch 3, which helps to form a strong coupling electric field region in the center of the patch and improve the field energy density; at the same time, by using the effect of the rectangular dielectric integrated waveguide, electromagnetic energy can be further restrained directly above the planar radiation patch, thereby affecting the field distribution change around the sensor and changing the resonant frequency of the sensor, so as to improve the detection sensitivity.

[0038] In addition, the central center region of the horizontal radiation patch 3 is the place where the electric field is the strongest and the energy is the most concentrated. By arranging the capacitor 331 at the center position of the horizontal radiation patch 3, the embodiment can not only improve the electric field concentration and sensitivity, but also realize resonant frequency adjustment.

[0039] More preferably, the edge of the sensor module is embedded with a first strip-shaped baffle 6 and a second strip-shaped baffle 7 symmetrically arranged in the length direction of the sensor module.

[0040] It should be noted that the first strip baffle 6 and the second strip baffle 7 are metal structures; the first strip baffle 6 and the second strip baffle 7 penetrate the horizontal radiating patch 3, the substrate integrated waveguide 4 and the metal ground plane 5 to form a baffle structure, further confining electromagnetic energy in the central region, reducing leakage and enhancing the resonance quality factor.

[0041] Accordingly, the first power supply terminal 31 extends outward from one end of the patch body, and the second power supply terminal 32 extends outward from the other end of the patch body. The connection between the first power supply terminal 31 and the second power supply terminal 32 and the patch body is etched with a port slot 34 extending along the length direction of the horizontally radiating patch 3, thereby allowing the electric field to enter more quickly.

[0042] As can be seen from the above, the substrate integrated waveguide sensor based on multi-ring coupled IDE of the present invention enhances the strong coupling effect of current by introducing ring-shaped symmetrical interdigital electrodes 33, and adds a metal baffle to concentrate energy at the center of the sensor, thereby generating a strong electric field above the sensor module, enabling the sensor module to store a large amount of electromagnetic energy, further improving the detection performance, and the overall structure is simple and reasonable.

[0043] See Figure 4 and Figure 5 , Figure 4 and Figure 5 This illustrates a second embodiment of the substrate-integrated waveguide sensor based on a multi-ring coupled IDE according to the present invention, and... Figure 1 and Figure 2 Unlike the first embodiment shown, in this embodiment, the outer contour of the sensor module is an elliptical structure.

[0044] It should be noted that in this embodiment, the outer contour of the sensor module is elliptical, which better matches the actual shape of the electric field, thereby reducing the area of ​​the sensor module.

[0045] like Figure 6 As shown, in this embodiment, the first " One end of the "type electrode" is connected to " The first electrode 337 is composed of a "type" electrode. The other end of the "type electrode" is connected to " The second electrode 338 is formed by a "-shaped" electrode. Along the length of the horizontal radiating patch 3, the heights of the first electrode 337, the first rectangular electrode 334, and the second electrode 338 decrease sequentially. One end of the "type electrode" is connected to " The "type" electrode constitutes the third electrode 339, the second " The other end of the "type electrode" is connected to the second " The fourth electrode 340 is formed by the electrode of the type of “”, and the heights of the third electrode 339, the second rectangular electrode 335 and the fourth electrode 340 increase in turn in the width direction of the horizontal radiation patch 3.

[0046] Therefore, the outer contour of the interdigital electrode 33 is also designed as an approximate elliptical shape in the embodiment, so that the electric field is more concentrated in the middle.

[0047] More preferably, the first and second strip baffles 6 and 7 are of an arc structure with the same curvature as the curvature of the elliptical structure, which better realizes the targeted reflection of the electric field and reduces leakage.

[0048] In addition, the electromagnetic energy can be maximized to be concentrated by properly adjusting the length and width of the interdigital electrode 33, so as to finally improve the sensitivity of the sensor. The specific parameter values are shown in Table 1 as follows:

[0049] Table 1

[0050]

[0051] As shown in Figure 7 , W v The central gap width is the width of the central gap, and the central gap forms the capacitance of the interdigital electrode itself. The narrower the central gap, the greater the capacitance, which leads to a decrease in the resonant frequency, so that the electric field is highly concentrated to form a very strong local electric field, thereby significantly improving the sensitivity.

[0052] H c The width of the first and second strip baffles 6 and 7 is the width of the first and second strip baffles 6 and 7, respectively, which form “side walls”. The first and second strip baffles 6 and 7 need to match the thickness of the sensor module to ensure that an effective “electric wall” is formed in the working frequency band to prevent energy leakage.

[0053] H d , H l , W s The electrode width is the width of the electrode. The wider the electrode, the larger the coupling capacitance area, which leads to a significant increase in the total capacitance, so that the resonant frequency is significantly reduced, which is more conducive to miniaturization. At the same time, the wider the electrode, the greater the area of the high electric field sensing region, which allows more electric field lines to interact with the object to be measured, thereby effectively improving the sensitivity.

[0054] H p , W gis the distance between the electrodes; the smaller the distance, the greater the coupling capacitance between the electrodes, resulting in an increase in the total capacitance; meanwhile, a smaller distance produces a stronger edge electric field, which is conducive to sensitivity; however, too small a distance increases the difficulty of manufacturing and may cause breakdown.

[0055] W k 、 W b is the length of the electrode; the length of the electrode determines the length of the current path, thereby affecting the equivalent inductance, wherein the greater the length, the greater the inductance, resulting in a decrease in the resonant frequency.

[0056] H a is the width of the port gap 34.

[0057] H q is the width of the first power supply end 31 and the second power supply end 32.

[0058] W z is the length of the first power supply end 31 and the second power supply end 32.

[0059] Wy is the half length of the sensor module, i.e., 1 / 2 of the length of the sensor module.

[0060] H x is the half width of the sensor module, i.e., 1 / 2 of the width of the sensor module.

[0061] The present application can effectively concentrate high electromagnetic energy in the structure by optimizing the length and width of the interdigital electrode.

[0062] The performance of the present embodiment is tested below to further describe the effect of the present embodiment:

[0063] As shown in Figure 8 , the electric field is highly concentrated around the concentrated capacitance at the center of the interdigital electrode; this is because the central gap constitutes a concentrated capacitance, according to the basic electromagnetic theory, the electric field strength E = V / d, when the potential difference V is constant, the smaller the central gap width d, the stronger the electric field strength E.

[0064] Meanwhile, the strong electric field will spread throughout all the electrodes between the interdigital electrode; each pair of adjacent electrodes becomes a powerful edge electric field generator, and the electric field lines of the generated edge electric field are roughly perpendicular to the surface of the horizontal radiation patch 3 and pass through the measured material.

[0065] In addition, the widespread electric field allows the tested material to effectively overlap with the high electric field region regardless of its size or placement. Moreover, the high electric field intensity and uniform distribution within the high electric field region ensure the strength and consistency of the interaction with the tested material.

[0066] Correspondingly, vertical electric field lines can pass through the material under test and interact with it most fully and directly, thus efficiently converting changes in the material's dielectric constant into changes in capacitance and resonant frequency.

[0067] like Figure 9 As shown, as the dielectric constant of the analyte increases from 1 to 11, S 21 Resonance point (i.e., scattering parameter S) 21 The frequency points corresponding to the "peaks" or "dips" that appear on the frequency variation curve show significant frequency deviation and gradually move towards lower frequencies. This is because when the object under test is placed in the measurement area, its dielectric constant and permeability affect the electromagnetic field distribution of the microwave sensor, causing disturbances in the field effect and resulting in changes in the resonant frequency.

[0068] In other words, different materials correspond to different resonance valleys; the higher the dielectric constant of a material, the lower its resonance valley is on the frequency axis. Specifically:

[0069] No-load condition: When no material is placed on top of the substrate-integrated waveguide sensor based on multi-ring coupled IDE, S 21 The curve will show a resonance valley at a specific frequency.

[0070] When the material under test is loaded: When the material under test covers the sensing area (above the interdigitated electrodes) of the substrate integrated waveguide sensor based on multi-ring coupled IDE, the dielectric constant of the material will increase the equivalent capacitance of the sensing area; at the same time, according to the LC resonance formula, the increase in capacitance will cause the resonant frequency to shift to the lower frequency direction.

[0071] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A multi-ring coupled IDE based substrate integrated waveguide sensor, characterized in that, The sensor module, the first SMA port and the second SMA port, the first SMA port and the second SMA port are symmetrically arranged at both ends of the sensor module, the sensor module comprises a horizontal radiation patch, a substrate integrated waveguide and a metal grounding plate arranged in sequence from top to bottom; The horizontal radiation patch comprises a patch body, a first power supply end, a second power supply end and an interdigital electrode etched on the upper surface of the patch body, the first power supply end is arranged at one end of the patch body and connected with the first SMA port, and the second power supply end is arranged at the other end of the patch body and connected with the second SMA port; The interdigital electrode comprises a capacitor, a first conductive electrode, a second conductive electrode, a first electrode unit, a second electrode unit, a third electrode unit and a fourth electrode unit, one transmission port of the first electrode unit and the fourth electrode unit is connected with one end of the capacitor through the first conductive electrode, one transmission port of the second electrode unit and the third electrode unit is connected with the other end of the capacitor through the second conductive electrode, the other transmission port of the first electrode unit and the second electrode unit is connected, and the other transmission port of the third electrode unit and the fourth electrode unit is connected; The first electrode unit, the second electrode unit, the third electrode unit and the fourth electrode unit each comprise a first rectangular electrode, a second rectangular electrode and a special-shaped electrode, the special-shaped electrode comprises a first " type electrode, a second " type electrode, a first " type electrode, a second " type electrode, a second " type electrode and a second " type electrode in sequence, the first rectangular electrode is arranged in a recessed area of the first " type electrode, and the second rectangular electrode is arranged in a recessed area of the second " type electrode.

2. The polycoupled IDE-based substrate integrated waveguide sensor of claim 1, wherein, The first electrode unit and the second electrode unit are symmetrically arranged in the width direction of the horizontal radiation patch, the third electrode unit and the fourth electrode unit are symmetrically arranged in the width direction of the horizontal radiation patch, the first electrode unit and the fourth electrode unit are symmetrically arranged in the length direction of the horizontal radiation patch, and the second electrode unit and the third electrode unit are symmetrically arranged in the length direction of the horizontal radiation patch.

3. The polycoupled IDE-based substrate integrated waveguide sensor of claim 1 or 2, wherein, The first One end of the "type electrode" is connected to the " The first electrode is composed of a "-shaped" electrode. The other end of the "type electrode" is connected to the " The first electrode, the first rectangular electrode, and the second electrode decrease in height sequentially along the length of the horizontal radiating patch.

4. The polycoupled IDE-based substrate integrated waveguide sensor of claim 1 or 2, wherein, The second One end of the second The other end of the second The other end of the second The height of the third electrode, the second rectangular electrode and the fourth electrode increases in turn in the width direction of the horizontal radiation patch.

5. The polycoupled-IDE-based substrate integrated waveguide sensor of claim 1, wherein, The outer contour of the sensor module is an elliptical structure.

6. The polycoupled-IDE-based substrate integrated waveguide sensor of claim 5, wherein, The edge of the sensor module is embedded with a first strip-shaped baffle and a second strip-shaped baffle symmetrically arranged in the length direction of the sensor module.

7. The polycoupled-IDE-based substrate integrated waveguide sensor of claim 6, wherein, The first strip-shaped baffle and the second strip-shaped baffle are arc-shaped structures with the same curvature as the curvature of the elliptical structure.

8. The polycoupled-IDE-based substrate integrated waveguide sensor of claim 1, wherein, The capacitor is arranged at the center position of the horizontal radiation patch.

9. The polycoupled-IDE-based substrate integrated waveguide sensor of claim 1, wherein, The first power supply end protrudes outward from one end of the patch body, and the second power supply end protrudes outward from the other end of the patch body.

10. The polycoupled-IDE-based substrate integrated waveguide sensor of claim 9, wherein, Port gaps extending in the length direction of the horizontal radiation patch are etched at the connection between the first power supply end and the second power supply end and the patch body.

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