A direction finding device based on coupled-detuned artificial surface plasmons

Abstract

The present invention discloses a direction finding device based on coupled-detuned artificial surface plasmons, which includes a dielectric substrate and two metal discs with grooves uniformly engraved from the edge to the center and having different sizes or materials. The two metal discs respectively form a first artificial surface plasmon resonator and a second artificial surface plasmon resonator that support different resonance frequencies; a metal is plated on the bottom surface of the dielectric substrate, and the two artificial surface plasmon resonators are symmetrically distributed on the upper surface of the dielectric substrate with the center of the dielectric substrate as the center of symmetry and the diagonal of the dielectric substrate as the axis, so as to form a coupled-detuned artificial surface plasmon structure. When an electromagnetic wave is incident, the two artificial surface plasmon resonators respond to the incoming wave and generate an artificial localized surface plasmon resonance mode. Direction finding can be carried out according to the corresponding relationship between the phase difference of the two artificial localized surface plasmon resonance modes and the incident angle of the incoming wave.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless direction finding, and particularly relates to a direction finding device based on coupled-detuned artificial surface plasmons. Background Art

[0002] Wireless direction finding technology is a technology that determines the direction of an incoming wave based on the propagation characteristics of electromagnetic waves and information such as the amplitude and phase of the incoming wave signal. It has broad application prospects in civilian fields such as wireless communication and transportation, as well as military fields such as technical reconnaissance and electronic countermeasures. Recently, with the rapid development of the radio technology field, wireless direction finding devices have shown a miniaturization trend. However, traditional direction finding equipment cannot simultaneously meet the requirements of device miniaturization and direction finding performance, and it is difficult to meet the development needs of current wireless direction finding technology.

[0003] Surface plasmons are generated when incident light waves irradiate the interface between a metal and a dielectric, causing collective oscillations of free electrons in the metal. Its electromagnetic field is localized on the metal surface and produces a field enhancement effect, thereby enhancing the interaction between light and matter. Therefore, it is widely used in the sensing field, including medicine, environmental monitoring, biotechnology drugs, and food monitoring, etc. Artificial surface plasmons are the low-frequency approximation of surface plasmons, which can confine electromagnetic waves within sub-wavelength dimensions, and have characteristics such as small volume and field enhancement. They have important application values in the design of highly sensitive and miniaturized sensors. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a direction finding device based on coupled-detuned artificial surface plasmons, which can simultaneously meet the requirements of miniaturization of the direction finding device and direction finding performance.

[0005] An embodiment of the present application provides a direction finding device based on coupled-detuned artificial surface plasmons, including a dielectric substrate and two metal circular disks that are uniformly grooved from the edge to the center and have different sizes or materials;

[0006] The two metal circular disks respectively form a first artificial surface plasmon resonator DSPR1 and a second artificial surface plasmon resonator DSPR2 that support different resonance frequencies through different sizes or materials;

[0007] The lower surface of the dielectric substrate is plated with metal, and the two artificial surface plasmon resonators are symmetrically distributed on the upper surface of the dielectric substrate with the center of the dielectric substrate as the center of symmetry and the diagonal of the dielectric substrate as the axis, thereby forming a coupled-detuned artificial surface plasmon structure.

[0008] Furthermore, the sizes of the two metal discs are different, specifically different in the outer circle radius, inner circle radius or disc thickness of the disc, where the outer circle radius is the radius of the metal disc and the inner circle radius is the radius of the un-grooved part of the metal disc.

[0009] Furthermore, the material of the metal disc is selected from copper, gold, and silver.

[0010] Furthermore, the material of the dielectric substrate is selected according to the dielectric constant of the material, and the metal plated on the dielectric substrate is copper, gold or silver.

[0011] Furthermore, the two artificial surface plasmon resonators respond to artificial localized surface plasmon resonance modes with different phase differences according to the incident wave direction.

[0012] The technical solutions provided by the embodiments of the present application may include the following beneficial effects:

[0013] As can be seen from the above embodiments, compared with the traditional direction finding device design scheme, the present application can take into account both the miniaturization requirements and the direction finding performance requirements, and has a wide range of application prospects.

[0014] 1. Miniaturization: The direction finding device of the present invention is based on a sub-wavelength artificial surface plasmon structure, realizing the miniaturized design of the device. The structure is simple and compact, convenient for processing, and easy to integrate.

[0015] 2. Sensitivity: The present invention introduces an artificial plasmonic structure into the direction finding device. This structure supports artificial localized surface plasmon resonance modes, and its field enhancement effect enhances the intensity of the received signal, thus improving the direction finding sensitivity.

[0016] 3. Precision: The direction finding principle of the present invention is based on the enhanced phase difference between two coupled detuned artificial surface plasmons. The coupling between the two plasmon resonators broadens the measured phase difference range between the two, thus improving the direction finding precision.

[0017] 4. Frequency tunability: The present invention can adjust the resonance frequency by changing the structural size or dielectric material, extending the direction finding device to high frequency / low frequency, and providing a flexible and adjustable platform for the direction finding requirements of electromagnetic waves in different frequency bands.

[0018] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0020] Figure 1Schematic diagram of a direction finding device based on coupled-detuned artificial surface plasmons shown according to an exemplary embodiment.

[0021] Figure 2 Spectrum diagram of an artificial plasmonic structure and dipole resonance mode diagram shown according to an exemplary embodiment.

[0022] Figure 3 Evolution spectrum diagram of artificial plasmonic structures with different inner diameters shown according to an exemplary embodiment.

[0023] Figure 4 Field enhancement contrast spectral line diagram after using an artificial plasmonic structure shown according to an exemplary embodiment.

[0024] Figure 5 Relationship diagram between measured phase difference and incident angle of incoming wave of a direction finding device based on coupled-detuned artificial surface plasmons shown according to an exemplary embodiment. Detailed implementation manners

[0025] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present application.

[0026] The terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "the", and "said" used in the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0027] It should be understood that although the terms first, second, third, etc. may be used in the present application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining".

[0028] The present application provides a direction finding device based on coupled-detuned artificial surface plasmons, such as Figure 1As shown in the figure, the device includes a dielectric substrate and two metal discs with grooves evenly engraved from the edge to the center of the circle and having different materials or sizes. The two grooved metal discs have different size parameters or materials, and thus form a first artificial surface plasmon resonator DSPR1 and a second artificial surface plasmon resonator DSPR2 that support different resonance frequencies respectively. The lower surface of the dielectric substrate is plated with metal. The two artificial plasmon resonators are symmetrically distributed on the upper surface of the dielectric substrate with the center of the dielectric substrate as the center of symmetry and the diagonal of the dielectric substrate as the axis, forming a coupled detuned artificial surface plasmon structure.

[0029] It should be noted that the difference in the sizes of the two metal discs specifically refers to the difference in the outer radius, inner radius or thickness of the discs. The outer radius is the radius of the metal disc, and the inner radius is the radius of the part of the metal disc that is not grooved.

[0030] The following description is based on an embodiment where the frequency of the incoming wave signal is 3.67 GHz.

[0031] Specifically, both of the two metal discs are evenly grooved at equal intervals from the edge to the center of the circle. Their inner diameters are r1 and r2 respectively, their outer diameters are R1 and R2 respectively, and their thicknesses are h c1 and h c2 , the number of grooves is N, and the duty cycle of the groove width to the groove period width is A. The two metal discs have different groove depths. The material of the metal disc is metal, which can be copper, gold, silver, etc. The two metal discs can use different materials. The closest distance from the edge to the edge of the two discs is d. The material of the dielectric substrate is selected according to the dielectric constant of the material. When selecting the dielectric constant, it is necessary to ensure that the composition structure of the dielectric substrate and the metal disc supports the surface plasmon resonance mode. For example, it can be polytetrafluoroethylene F4BTMS220. The dielectric constant of the material of the dielectric substrate is ε, the length is L, and the thickness is h d ; the metal plated on the dielectric substrate can be copper, gold, silver, etc., and the thickness of the copper plating is h b . In specific implementation, the above materials and parameter selections can be appropriately adjusted according to requirements. When adjusting, it is necessary to ensure that the composition structure of the dielectric substrate and the metal disc supports the surface plasmon resonance mode. In this exemplary embodiment, for the direction finding of 3.67 GHz electromagnetic waves, the materials of the metal discs are both copper, the number of grooves N = 60, and the duty cycle A = 50% (that is, within one cycle of the groove, the grooved space: the non-grooved space = 1:1); the outer diameter R1 = R2 = R = 12 mm, and the thickness h c1 = h c2 = h c= 0.0175 mm, the inner diameter r1 of DSPR1 is 6 mm, and the inner diameter r2 of DSPR2 is 6.2 mm; the nearest spacing distance d from the edge of DSPR1 to the edge of DSPR2 is 10 mm. The dielectric substrate material is polytetrafluoroethylene F4BTMS220, the dielectric constant ε = 2.2, and the bottom metal plating material is copper. The length L of the dielectric substrate is 80 mm, the thickness h d = 2 mm, and the thickness of the copper plating on the bottom surface is h b = 0.0175 mm.

[0032] It should be noted that how to adjust the materials and parameters according to requirements is a conventional technical means in this field and will not be elaborated here.

[0033] As Figure 2 shown, it is the frequency spectrum diagram of the first artificial surface plasmon and the second artificial surface plasmon and the supported artificial localized surface plasmon resonance mode in the embodiment of the present invention. It can be seen from the figure that due to different grooving depths, the frequency spectrum resonance peak positions of the first and second artificial surface plasmon structures with inner circle radii of 6 mm and 6.2 mm are ω1 = 3.655 GHz and ω2 = 3.685 GHz respectively, there is a resonance frequency detuning, and the central resonance frequency of the coupled detuned artificial surface plasmon system formed by them is ω0 = (ω1 + ω2) / 2 = 3.67 GHz; and both artificial surface plasmon structures support the dipole resonance mode at the resonance peak.

[0034] It should be noted that for incoming wave signals of other frequencies, by designing the parameters of the two artificial surface plasmon structures, such as: inner circle radius, outer circle radius, thickness or material, etc., the central resonance frequency of the coupled detuned artificial surface plasmon system can be adjusted to be consistent with the incoming wave signal frequency, which can provide a platform for the direction finding requirements of electromagnetic waves in different frequency bands. Taking the inner circle radius r as an example, as Figure 3 shown, it is the evolution of the frequency spectrum diagram of artificial surface plasmon resonators with different inner circle radii; it can be confirmed from the figure that by adjusting the artificial surface plasmon parameters, direction finding can be achieved for incoming wave signals of other frequencies.

[0035] As Figure 4 shown, it is the field strength spectral line obtained by experimental detection under the far-field illumination of the horn antenna in the present invention. It can be seen from the figure that under the same measurement conditions, the field strength measured using the artificial surface plasmon structure is enhanced by about 33 times, greatly improving the direction finding sensitivity.

[0036] As Figure 5As shown, it is a graph showing the relationship between the phase difference measured by a coupled-detuned artificial surface plasmon direction-finding device and a non-coupled antenna direction-finding device respectively and the incident angle of a 3.67 GHz incoming wave. It can be seen from the graph that the phase difference measured by the coupled-detuned artificial surface plasmon lateral device and the incident angle of the incoming wave show a one-to-one monotonically increasing relationship; and compared with the measurement results of the independent antenna direction-finding device (the phase difference range is 0° to 130.4°), the measured phase difference range is significantly broadened (the phase difference range is 0° to 159.4°). Therefore, it shows that the direction-finding device based on coupled-detuned artificial surface plasmons can achieve full-range direction-finding for incoming waves with directions from 0° to 90°, and its enhanced phase difference can further improve the direction-finding accuracy.

[0037] It should be noted that in the specific implementation, the direction-finding device needs to be fixed first, and the same probes are set at positions A and B of the device (as Figure 1 shown), and the phase measurement circuit is connected through the probes. When direction-finding for the incoming wave, the electric field phase value is measured through the probes and transmitted to the direction-finding circuit to calculate the phase difference between the electric fields at points A and B, and then the incident angle of the incoming wave signal can be obtained.

[0038] When electromagnetic waves are incident at different angles, two artificial surface plasmon resonators respond to the incoming wave, presenting artificial localized surface plasmon resonance modes with different phases. Direction-finding can be carried out according to the corresponding relationship between the phase difference and the incident angle of the incoming wave.

[0039] After considering the specification and the practice disclosed herein, those skilled in the art will readily conceive of other embodiments of the present application. The present application is intended to cover any variations, uses, or adaptations of the present application, which follow the general principles of the present application and include the common general knowledge or conventional technical means in the technical field not disclosed in the present application.

[0040] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A direction finding device based on coupled-detuned artificial surface plasmons, characterized in that, It includes a dielectric substrate and two metal discs with grooves evenly engraved from the edge to the center of the circle and having different sizes or materials; The two metal discs respectively form a first artificial surface plasmon resonator DSPR1 and a second artificial surface plasmon resonator DSPR2 that support different resonance frequencies through different sizes or materials; The lower surface of the dielectric substrate is plated with metal. The two artificial surface plasmon resonators are symmetrically distributed on the upper surface of the dielectric substrate at intervals with the center of the dielectric substrate as the center of symmetry and the diagonal line of the dielectric substrate as the axis, thereby forming a coupled detuned artificial surface plasmon structure; When electromagnetic waves are incident at different angles, the two artificial surface plasmon resonators respond to the incoming waves, presenting artificial localized surface plasmon resonance modes with different phases, and direction finding is performed according to the corresponding relationship between the phase difference and the incoming wave incident angle.

2. The direction finding device based on coupled-detuned artificial surface plasmons according to claim 1, characterized in that, The sizes of the two metal discs are different, specifically, the outer radius, inner radius or thickness of the discs are different. The outer radius is the radius of the metal disc, and the inner radius is the radius of the un-grooved part of the metal disc.

3. The direction finding device based on coupled-detuned artificial surface plasmon according to claim 1, characterized in that, The material of the metal disc is selected from copper, gold, and silver.

4. The direction finding device based on coupled-detuned artificial surface plasmon according to claim 1, wherein The material of the dielectric substrate is selected according to the dielectric constant of the material, and the metal plated on the dielectric substrate is copper, gold or silver.

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