Ka-band all-dielectric-material high-Q-value sensor

Abstract

The invention relates to a Ka wave band all-dielectric material sensor, the unit structure comprises a substrate layer, a hollow cylinder structure made of the same type of material is superposed on the front surface of the substrate layer, the substrate layer of each sensor unit is square, the side length is 9.7-10mm, the bottom of the hollow cylinder structure is located in the center of the substrate layer, the inner diameter of the hollow cylinder structure is 1.4-1.6 mm, and the wall thickness is 1mm. The height of the hollow cylinder structure is 8-10 mm. Through 2 * 2 or 3 * 3 array combination, when the hollow cylinders are different in height or diameter, an electromagnetically-like induced transparency phenomenon is generated, and a slow light effect is achieved. When the sensor is used as a sensor, a measured substance filling cavity is formed in the hollow cylinder structure. The structure is simple, the material cost is low, the sensor characteristics can be realized, the electromagnetic induction effect can be generated, and potential application prospects are achieved in the fields of slow light devices and sensors.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic materials, and in particular to applications of a high-Q value sensor based on a Ka-band all-dielectric material and a similar electromagnetic induced transparency effect. Background Art

[0002] Metamaterials are artificially constructed electromagnetic structures with unique electromagnetic responses, such as negative refractive index, negative magnetic permeability and negative dielectric constant. According to the different constituent materials, metasurfaces can be divided into metal metamaterials and all-dielectric metamaterials. Traditional metamaterials are mainly composed of precious metal materials, but because metals have ohmic losses, the quality factor (Q factor) of metamaterial structures based on metal structures is generally very low, and the FOM value (Figure of Merit) is generally dozens, which greatly limits the application of metamaterials in the field of sensing. All-dielectric metamaterials have a wide range of applications in optical bands, infrared bands, terahertz bands, Ka bands and other bands. Researchers are in the fields of wave absorption, filters, and sensors. Since all-dielectric metamaterials have no ohmic losses, their Q values ​​are generally high, and their FOM values ​​used in the field of sensing are also large, so they have potential applications in the field of sensing.

[0003] The electromagnetically induced transparency effect is a coherent control technology. Initially, the atomic energy level is coherently controlled by laser, which causes quantum interference on different excitation routes, and then eliminates the absorption of light by atoms at the resonant frequency. Because in the passband excited by it, there will be a strong dispersion effect, which greatly reduces the group velocity of light, or even makes the light "stop", thereby realizing solid-state storage of optical information. The electromagnetically induced transparency effect in the microwave band is strictly speaking a quasi-electromagnetic induced transparency effect. There are three main ways to achieve it: (a) low-Q bright mode coupled with external field + high-Q dark mode coupled with bright mode; (b) low-Q bright mode coupled with external field + high-Q quasi-dark mode coupled with external field; (c) Fano effect caused by structural asymmetry; (d) Mie resonance of structural symmetry and Mie resonance generated by rotationally symmetric structure.

[0004] The literature All-dielectric metasurface analogue of electromagnetically induced transparency (Nature communications, 2014, 5(1): 5753.) uses all-dielectric metasurfaces to achieve electromagnetically induced transparency effects in the 1320nm-1420nm band. The structure is processed on a Quartz substrate to achieve the electromagnetically induced transparency phenomenon by coupling silicon rings and silicon rods in the form of bright and dark modes. The research results show that the Q of the structure reaches 483, and the figure-of-merit (FOM) of the refractive index sensor reaches 103. Compared with other major 3D printing materials and methods, ABS / PLA, the material of fused deposition modeling (FDM) 3D printing technology, is widely used due to its low cost and relative cleanliness (no need to use irritating chemicals), and has attracted the attention of researchers in the preparation of all-dielectric metamaterials.

[0005] Many electromagnetic wave devices based on 3D printing technology have been reported in the prior art. The document 3D Printing Materials and Techniques for Antennas and Metamaterials: A survey of the latest advances (IEEE Antennas and Propagation Magazine, 2023, 65 (3): 10) systematically reviews the preparation of metamaterials using 3D printing materials. The document 3-D printed swastika-shaped ultrabroadband water-based microwave absorber (IEEE Antennas and Wireless Propagation Letters, 2020, 19 (5): 821-825.) proposes a cross-shaped ultra-wideband metamaterial absorber. The designed absorber is prepared by 3D printing with PLA material. The absorber can achieve more than 90% in the frequency band of 9.3-49.0GHz, and also performs well under wide incident angles. The present invention focuses on realizing the electromagnetically induced transparency phenomenon in the Ka band through Mie resonance in all-dielectric metamaterials. Summary of the invention

[0006] The object of the present invention is to utilize the above-mentioned material to produce a transmission type sensor with high Q value sensor characteristics, wherein the sensor has sensing characteristics and electromagnetically induced transparency characteristics.

[0007] In order to achieve the above object, the present invention adopts the following technical solution.

[0008] The Ka-band all-dielectric material high-Q value sensor of the present invention is composed of sensor units arranged in a 2×2 (or 3×3) array of all-dielectric materials, each sensor unit includes a base layer and a hollow cylindrical structure on the base layer; the base layer of each sensor unit is square, with a side length of 9.7-10mm, the bottom of the hollow cylindrical structure is located at the center of the base layer, the inner diameter of the hollow cylindrical structure is 1.4-1.6mm, the wall thickness is 1mm, and the height of the hollow cylindrical structure is 8-10mm; the base layer of 4 (or 9) sensor units is an integrated flat plate with a thickness of 1-1.4mm, wherein only one sensor unit has a hollow cylindrical structure height different from the other hollow cylindrical structures in the array, and the other hollow cylindrical structures have the same height. The sensor units arranged in this array can be used individually or in a plurality of arrays arranged continuously.

[0009] The materials of the base layer and the hollow cylindrical structure are both ABS or PLA, and the dielectric constant of the material is 2.47-3.11.

[0010] When the applied electromagnetic wave is a transverse electric wave or a transverse magnetic wave, and is transmitted from the hollow cylindrical structure to the substrate layer, the arrayed sensor units will produce transmission characteristics at a specific frequency point (and the results of the applied transverse electric wave and the transverse magnetic wave are almost the same), that is, the arrayed sensor unit structure is insensitive to the polarization of the electromagnetic wave, and a high Q value is generated at the transmission frequency point. In addition, the arrayed sensor unit structure can also produce a similar electromagnetically induced transparency effect, and can be used as a slow light device.

[0011] When different substances to be measured are filled in the hollow cylindrical structure, the overall dielectric constant changes accordingly, the resulting transmission spectrum will have an obvious shift, and the obtained transmission window will change. Based on this characteristic, it can be used as a sensor. When used as a sensor, the hollow cylindrical structure is filled with a cavity filled with the substance to be measured.

[0012] When the size of the sensor unit is proportionally reduced by 1 time or enlarged by 1 time, a high Q value sensor can also be formed, and the spectrum range will be enlarged by 1 time or reduced by 1 time accordingly.

[0013] The advantages of the present invention are: using 3D printing technology to realize low-cost all-dielectric material microwave devices, and realizing quasi-electromagnetic induced transparency phenomenon through Mie resonance generated by periodic arrangement of devices. Specifically, the structure can have a high Q value, and when the measured medium is filled in the hollow cylindrical structure, its transmission spectrum also changes accordingly, so the structure has sensing characteristics; according to the characteristics of the quasi-electromagnetic induced transparency phenomenon generated, it can also be used as a slow light device. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 12 are the front view and the side view of the unit structure of the present invention.

[0015] Figure 2 It is the front view and side view of the 2×2 array structure of the present invention.

[0016] Figure 3 This is a graph showing the variation of transmittance of the 2×2 array structure of the present invention with frequency.

[0017] Figure 4 yes Figure 3 The magnetic field distribution at the transmission valley points of 30.71 GHz, 30.83 GHz and the transmission peak of 30.755 GHz in the transmission spectrum.

[0018] Figure 5 It is the effect of changing the outer diameter R of the hollow cylinder on the transmission spectrum.

[0019] Figure 6 It is the effect of changing the inner diameter r0 of the hollow cylinder on the transmission spectrum.

[0020] Figure 7 It is the influence on the transmission spectrum when the outer diameter R of the hollow cylinder is too large or too small.

[0021] Figure 8 (a)(b)(c) are the transmission spectra corresponding to the structural scaling.

[0022] Fig. 9 It is the effect of changing the thickness of the substrate layer T0 on the transmission spectrum.

[0023] Fig.10 It is the effect of changing the height T1 of the hollow cylinder on the transmission spectrum.

[0024] Fig.11 (a)(b)(c) show the effect of changing the periodic size of the structure on the transmission spectrum.

[0025] Fig.12 This is the effect of only one hollow cylinder and a 2×2 array structure on the transmission spectrum.

[0026] Fig.13 This is the effect of the height change of the hollow cylinder on the transmission spectrum when the structure is 3×3.

[0027] Fig.14 It is the effect of changing the structural material on the transmittance of the structure of the embodiment of the present invention.

[0028] Fig.15 It is the influence of the hollow cylindrical structure filled with the measured material (dielectric constant) changing on the transmittance of the structure of the embodiment of the present invention.

[0029] Fig.16It is a result diagram of the quality factor Q value and the sensor sensitivity S frequency change at the low-frequency resonance point 29.69 GHz of the structure of the present invention.

[0030] Fig.17 It is a result diagram of the quality factor Q value and the sensor sensitivity S frequency change at the low-frequency resonance point 30.71 GHz of the structure of the present invention.

[0031] Fig.18 It is a result diagram of the quality factor Q value and the sensor sensitivity S frequency change at the low-frequency resonance point 30.83 GHz of the structure of the present invention.

[0032] Fig.19 It is a graph showing the changes in group delay and group index produced by the structure of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0034] like Figures 1-2 As shown, the Ka-band all-dielectric material high-Q value sensor of the present invention includes sensor units arranged in a 2×2 array of all-dielectric materials (the 3×3 array structure is similar, not shown in the figure). Figure 1 It is a single sensor unit, each sensor unit includes a base layer 1 and a hollow cylindrical structure 2, the bottom of the hollow cylindrical structure 2 is located at the center of the base layer 1, and is connected to the base layer 1 as a whole. The cross section of the base layer 1 is a square shape with a side length of 9.7-10mm; the wall thickness of the hollow cylinder is 1mm, the outer diameter of the hollow cylinder is 2.4-2.6mm, the inner diameter is 1.4-1.6mm, and the height is 8-10mm.

[0035] The base layer 1 of the four sensor units is an integral flat plate, and preferably, the base layer 1 has a thickness of 1-1.4 mm. The hollow cylindrical structures 2 of three sensor units have the same height, and the height of the hollow cylindrical structure 2 of one sensor unit is different from that of the other three.

[0036] During specific processing, the fused deposition modeling (FDM) 3D printer is used for processing, and the dielectric material is ABS / PLA, etc., and the dielectric constant varies from 2.47 to 3.11. From a process perspective, the size of the unit structure can be appropriately scaled, and its frequency point will produce a certain red shift and blue shift phenomenon, which are all within the scope of protection of this patent. For example, if the size of the structure is reduced by 1 times or enlarged by 1 times, Figure 8 As shown, Figure 8 (a) is the transmission spectrum when the structure is reduced by 1 times. Figure 8 (b) is the transmission spectrum of the original structure, Figure 8(c) is the transmission spectrum when the structure is magnified by 1 times. When the structure is at normal value, reduced by 1 times and magnified by 1 times, the spectrum range will be magnified by 1 times and reduced by 1 times accordingly. This phenomenon satisfies the electromagnetic wave scaling theory.

[0037] The positions of the four sensor units are described corresponding to the four quadrants of the rectangular coordinate system, wherein the height of one of the four quadrants is different from the heights of the other three quadrants, for example, the height of the hollow cylindrical structure 2 in the first quadrant is different from the heights of the hollow cylindrical structures 2 in the second, third and fourth quadrants.

[0038] like Figure 3 As shown in the figure, taking the base layer 1 with a thickness of 1mm, the outer diameter of the hollow cylindrical structure 2 with an inner diameter of 2.4mm and 1.4mm, the height of the hollow cylinder in the first quadrant with a height of 9mm, and the height of the hollow cylinder in the second, third and fourth quadrants with a height of 10mm as an example, three resonant frequency points will be generated at 29.69GHz, 30.71GHz and 30.83GHz. Among them, a very narrow transmission peak will be generated at 30.755GHz, which means that at this time, the structure can produce a phenomenon similar to electromagnetically induced transparency.

[0039] like Figure 4 Shown are the magnetic field distributions at the transmission valley points of 30.71 GHz and 30.83 GHz and the transmission peak point of 30.755 GHz.

[0040] like Figure 4 As shown in (a), at 30.71 GHz, the magnetic field is mainly distributed between the hollow cylinders in the second and fourth quadrants and the substrate, indicating that the resonance frequency point is caused by the resonance between the hollow cylinders in the second and fourth quadrants and the substrate. Figure 4 (b) shows the magnetic field distribution at the resonance peak of 30.755 GHz. It can be found that at this frequency point, the magnetic field distribution between the hollow cylinder in the second and fourth quadrants and the substrate is weakened, while the resonance between the hollow cylinder in the first and third quadrants and the substrate is enhanced. Figure 4 (c) It can be clearly seen from the magnetic field distribution at 30.83 GHz that at this time, the resonance between the hollow cylinders and the substrate in the first and third quadrants is enhanced. Since the structure is a symmetrical structure, Mie resonance is generated between the hollow cylinders and the substrate, resulting in the occurrence of electromagnetically induced transparency phenomenon.

[0041] like Figures 5-6 As shown, the influence of changing the outer diameter R of the hollow cylindrical structure 2 on the transmission spectrum and the influence of changing the inner diameter r0 of the hollow cylindrical structure 2 on the transmission spectrum are respectively shown.

[0042] When the outer diameter R of the hollow cylindrical structure 2 is increased, the resonant frequency at the low frequency point of 29.69 GHz hardly changes. The major change is that the high-frequency resonance point of the electromagnetically induced transparent window shifts to the left with the increase of R, causing the electromagnetically induced transparent window to narrow.

[0043] Figure 6 It is shown that when the inner diameter r0 of the hollow cylindrical structure 2 increases, the resonant frequency will shift to the left, that is, the wall thickness of the hollow cylindrical structure 2 has a greater impact on the resonant frequency. This is because the Mie resonance is mainly generated between the hollow cylindrical structure and the substrate. If the outer diameter of the hollow cylinder is too large or too small, the resulting transmission spectrum changes significantly. For example, when the outer diameter R is 2.9mm and 2.3mm, Figure 7 As shown in Figure 1, the structure cannot produce electromagnetically induced transparency. Changes in the wall thickness and length and width of the above materials will cause a certain range of frequency shifts, such as Figure 5 , as shown in 6.

[0044] like Fig. 9 As shown, the height of the hollow cylindrical structure in the first quadrant is 9mm, the outer diameter is 2.6mm, and the inner diameter is 1.6mm. The height of the hollow cylinder in the second, third, and fourth quadrants is 10mm, the outer diameter is 2.6mm, and the inner diameter is 1.6mm. When the thickness T0 of the substrate plate changes from 1-1.4mm, the change in transmittance shows that the high-frequency part will produce obvious frequency shift.

[0045] like Fig.10 As shown in the figure, the outer diameter of the hollow cylinder structure in the first quadrant is 2.6mm, the inner diameter is 1.6mm, and the height T2 varies from 8.6-9.4mm. The outer diameter of the hollow cylinder in the second, third and fourth quadrants is 2.6mm, the inner diameter is 1.6mm, and the height T1 varies in the range of 9.6-10.4mm. It can be seen that the high-frequency part will also produce obvious frequency shifts and generate new frequency components.

[0046] like Fig.11 The effect on the transmission spectrum when the periodic size P of the unit structure (i.e., the square side length of the substrate layer of a single sensor unit) changes within different ranges is shown. Fig.11 (a) Period 8-12mm, Fig.11 (b) Period 9.5-10.5 mm, Fig.11 (c) Period 9.6-10 mm. It can be seen that the EIT-like phenomenon can occur in the range of 9.7-10 mm. Periods exceeding this range will not produce the EIT-like phenomenon.

[0047] Considering the impact of different structures on EIT-like phenomena, Fig.12 , Fig.13 Shown are the changes in transmittance for different array combinations. Fig.12 Shown is the transmittance comparison between a single sensor unit with only one hollow cylinder and a sensor unit with a 2×2 array structure. It is obvious that the 2×2 array structure can produce an EIT-like phenomenon. Fig.13Shown is a comparison of the transmittance of a 3×3 array structure, where the height of one hollow cylinder is different from the others, such as Fig.12 The black circle in the middle indicates that the height is different from that of other hollow cylinders. It can be seen that different positions have a certain influence on the transmittance, which is mainly manifested in the generation of new high-frequency components. Therefore, the present invention can also use the above-mentioned 3×3 sensor unit arrangement form.

[0048] like Fig.14 As shown in the figure, taking 3D printing material ABS as an example, when the dielectric constant of ABS changes, it will affect the transmittance. When the dielectric constant increases, the low-frequency resonance point will shift to the left, and the electromagnetically induced transparent window will also shift significantly to the left, and the offset is greater than that of the low-frequency resonance point, that is, the dielectric constant of ABS has a greater impact on the electromagnetically induced transparent window.

[0049] like Fig.15 As shown, when the substance being measured in the hollow cylindrical structure is changed, its dielectric constant changes accordingly. When the dielectric constant increases from 1 to 1.5, the transmission spectrum produced by the structure of the present invention will have an obvious left shift, that is, the structure has sensing characteristics and can be used as a sensor.

[0050] by Figure 16-18 For example, the following is a graph showing the quality factor Q value and sensor sensitivity S of the sensor structure of the present invention at the low-frequency resonance point of 29.69 GHz and 30.71 GHz as a function of frequency. The horizontal axis is the dielectric constant ε of the measured medium, the left vertical axis is the quality factor Q value, and the right vertical axis is the sensor sensitivity S value. Fig.16 It can be seen that the Q value varies between 300-750. Fig.17 It can be found that the Q value varies from 460 to 1150, that is, the structure of the present invention can produce a high Q value. Figure 16-18 It can be seen that the sensitivity S at the three resonant frequency points changes smoothly with the dielectric constant ε of the measured material, indicating that the structure of the present invention has good sensing characteristics.

[0051] The sensor unit structure of the present invention also has a similar electromagnetic induced transparency effect. Fig.19 For example, in the frequency range of 29-32 GHz, especially in the quasi-electromagnetically induced transparent window of 30.71 GHz-30.83 GHz, it can be seen that the group index is above 600 (right vertical axis), and the group delay (left coordinate) is larger in the frequency band range of the gray area (quasi-EIT window), indicating that the structure has a slow light effect and can be used as a slow light device.

[0052] To further demonstrate the characteristics of the present invention, the following are more experimental data of the sensor structure of the present invention. The parameters of the unit structure of the materials used in the experiment are as follows: the base layer 1 material is ABS, with a thickness of 1mm and a side length of 10mm; the hollow cylindrical structure 2 is the same type of ABS material with an outer diameter of 2.6mm and an inner diameter of 1.6mm; it is arranged in a 2×2 array, where the height of the hollow cylindrical structure in the first quadrant is 9mm, and the height of the hollow cylindrical structure in the second, third and fourth quadrants is 10mm, and it is prepared using 3D printing technology using fused deposition modeling.

[0053] like Fig.15 As shown, at room temperature, the substances to be tested with dielectric constants of 1, 1.1, 1.2, 1.3, 1.4 and 1.5 are placed in the hollow cylindrical structure 2 of the present invention as the substance-filled cavity, and the following is obtained through testing:

[0054] When the measured material with a dielectric constant of 1 is selected, the resonant frequencies are 29.736, 30.773, and 31.017 GHz respectively;

[0055] When the measured material with a dielectric constant of 1.1 is selected, the resonant frequencies are 29.624, 30.634, and 30.905 GHz respectively;

[0056] When the measured material with a dielectric constant of 1.2 is selected, the resonant frequencies are 29.538, 30.489, and 30.806 GHz respectively;

[0057] When the measured material with a dielectric constant of 1.3 is selected, the resonant frequencies are 29.446, 30.34, and 30.723 GHz respectively;

[0058] When the measured material with a dielectric constant of 1.4 is selected, the resonant frequencies are 29.35, 30.19, and 30.634 GHz respectively;

[0059] When the material under test has a dielectric constant of 1.5, the resonant frequencies are 29.266, 30.04, and 30.556 GHz respectively.

[0060] It can be seen that by changing the substance to be measured in the hollow cylindrical structure of the present invention, the position of the resonant frequency point will change accordingly, thereby realizing the sensing characteristics of the present invention.

[0061] In summary, it can be seen that the present invention can realize a sensor unit structure of all-dielectric materials with high Q value through low-cost 3D printing technology and materials. The structure can also produce a similar electromagnetic induced transparency effect, so it can also be used as a slow light device. The present invention has the characteristics of low cost, simple structure and low loss, and can provide guidance for the design of Ka-band radio frequency devices.

Claims

1. A Ka-band all-dielectric high-Q sensor, characterized by: The invention relates to a sensor unit arranged in a 2×2 array of all-dielectric materials, wherein each sensor unit comprises a base layer (1) and a hollow cylindrical structure (2) on the base layer (1); the base layer (1) of each sensor unit is square with a side length of 9.7-10 mm, the bottom of the hollow cylindrical structure (2) is located at the center of the base layer (1), the inner diameter of the hollow cylindrical structure (2) is 1.4-1.6 mm, the wall thickness is 1 mm, and the height of the hollow cylindrical structure (2) is 8-10 mm; the base layers (1) of four sensor units are an integral flat plate, wherein the hollow cylindrical structures (2) of three sensor units have the same height, and the height of the hollow cylindrical structure (2) of one sensor unit is different from that of the other three.

2. A Ka-band all-dielectric high-Q sensor, characterized by: The invention relates to a sensor unit arranged in a 3×3 array of all-dielectric materials, wherein each sensor unit comprises a base layer (1) and a hollow cylindrical structure (2) on the base layer (1); the base layer (1) of each sensor unit is square with a side length of 9.7-10 mm, the bottom of the hollow cylindrical structure (2) is located at the center of the base layer (1), the inner diameter of the hollow cylindrical structure (2) is 1.4-1.6 mm, the wall thickness is 1 mm, and the height of the hollow cylindrical structure (2) is 8-10 mm; the base layers (1) of the nine sensor units are an integral flat plate, wherein the hollow cylindrical structures (2) of eight of the sensor units are of the same height, and the height of the hollow cylindrical structure (2) of one sensor unit is different from that of the other eight.

3. The Ka-band all-dielectric material high-Q sensor according to claim 1 or 2, characterized in that: The base layer (1) has a thickness of 1-1.4 mm.

4. The Ka-band all-dielectric material high-Q sensor according to claim 1 or 2, characterized in that: The materials of the base layer (1) and the hollow cylindrical structure (2) are both ABS or PLA, and the dielectric constant of the material is 2.47 to 3.

11.

5. The Ka-band all-dielectric material high-Q sensor according to claim 1 or 2, characterized in that: When the external electromagnetic wave is a transverse electric wave or a transverse magnetic wave, and is transmitted from the hollow cylindrical structure (2) to the base layer (1), the array-arranged sensor units will produce transmission characteristics at a specific frequency point, and the results of the external transverse electric wave and the transverse magnetic wave are consistent, that is, the array-arranged sensor unit structure is insensitive to the polarization of the electromagnetic wave, and a high Q value is generated at the transmission frequency point.

6. The Ka-band all-dielectric material high-Q sensor according to claim 1 or 2, characterized in that: When used as a sensor, the hollow cylindrical structure (2) contains a cavity filled with the substance to be measured. When different substances to be measured are filled in the hollow cylindrical structure (2), the overall dielectric constant changes accordingly, the generated transmission spectrum will have a significant shift, and the obtained transmission window will change.

7. The Ka-band all-dielectric material high-Q sensor according to claim 1 or 2, characterized in that: When the size of the sensor unit is proportionally reduced by 1 time or enlarged by 1 time, a high Q value sensor can also be formed, and the spectrum range will be enlarged by 1 time or reduced by 1 time accordingly.

8. The Ka-band all-dielectric material high-Q sensor according to claim 1 or 2, characterized in that: When the external electromagnetic wave is a transverse electric wave or a transverse magnetic wave and is transmitted from the hollow cylindrical structure (2) to the base layer (1), the array-arranged sensor units can produce an electromagnetically induced transparency effect, and according to the characteristics of the electromagnetically induced transparency phenomenon, they can be used as slow light devices.

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