Direction finding device based on coupling detuned spoof surface plasmons

Abstract

Disclosed in the present invention is a direction finding device based on coupling detuned spoof surface plasmons, comprising a dielectric substrate and two metal disks which are each evenly grooved from the edge to the center and have different sizes or materials. The two metal disks respectively form a first spoof surface plasmon resonator and a second spoof surface plasmon resonator which support different resonant frequencies; the bottom surface of the dielectric substrate is plated with metal; and the two spoof surface plasmon resonators are distributed on the upper surface of the dielectric substrate at an interval, with the center of the dielectric substrate as a symmetry center and a diagonal line of the dielectric substrate as an axis, thereby forming a coupling detuned spoof surface plasmon structure. When there are incident electromagnetic waves, the two spoof surface plasmon resonators respond to the incident waves to generate spoof localized surface plasmon resonance modes, so that direction finding can be carried out on the basis of the correspondence between a phase difference between the two spoof localized surface plasmon resonance modes and an angle of incidence of the incident waves.

Description

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

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

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

[0003] Surface plasmons are the collective oscillations of free electrons in metals caused by incident light waves striking the interface between metals and dielectrics. Their electromagnetic field is localized on the metal surface, creating a field enhancement effect that enhances the interaction between light and matter. Consequently, they are widely used in sensing applications, including medicine, environmental monitoring, biopharmaceuticals, and food monitoring. Artificial surface plasmons are a low-frequency approximation of surface plasmons that can confine electromagnetic waves to subwavelength dimensions. Their compact size and field enhancement make them valuable in the design of highly sensitive, miniaturized sensors.

[0004] Summary of the Invention

[0005] 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 and direction-finding performance of the direction-finding device.

[0006] The embodiment of the present application provides a direction-finding device based on coupled detuned artificial surface plasmons, comprising a dielectric substrate and two metal discs with grooves uniformly cut from the edge to the center and having different sizes or materials;

[0007] The two metal discs are formed by different sizes or materials to form a first artificial surface plasmon resonator DSPR1 and a second artificial surface plasmon resonator DSPR2 supporting different resonant frequencies respectively;

[0008] The lower surface of the dielectric substrate is plated with metal, and two artificial surface plasmon resonators are 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.

[0009] Furthermore, the two metal discs have different sizes, specifically, different outer radius, inner radius or thickness of the discs, wherein the outer radius is the radius of the metal disc, and the inner radius is the radius of the ungrooved portion of the metal disc.

[0010] Furthermore, the material of the metal disc is selected from copper, gold, and silver.

[0011] 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.

[0012] Furthermore, the two artificial surface plasmon resonators respond to artificial localized surface plasmon resonance modes with different phase differences according to the directions of incoming waves.

[0013] The technical solutions provided by the embodiments of the present application may have the following beneficial effects:

[0014] It can be seen from the above embodiments that, compared with the traditional direction-finding device design, the present application can take into account both miniaturization requirements and direction-finding performance requirements, and has broad application prospects.

[0015] 1. Miniaturization: The direction-finding device of the present invention is based on a subwavelength artificial surface plasmon structure, which enables a miniaturized device design with a simple and compact structure, convenient processing, and easy integration.

[0016] 2. Sensitivity: The present invention introduces an artificial plasmon structure into the direction-finding device. This structure supports an artificial localized surface plasmon resonance mode, and its field enhancement effect enhances the strength of the received signal, thereby improving the direction-finding sensitivity.

[0017] 3. Accuracy: 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 range of the measured phase difference between them, thereby improving the direction-finding accuracy.

[0018] 4. Adjustable frequency: The present invention can adjust the resonant frequency by changing the structural dimensions or dielectric material, extending the direction-finding device to high / low frequencies, and providing a flexible and adjustable platform for electromagnetic wave direction-finding needs in different frequency bands.

[0019] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0021] FIG1 is a schematic structural diagram of a direction finding device based on coupled-detuned artificial plasmons according to an exemplary embodiment.

[0022] FIG. 2 is a spectrum diagram and a dipole resonance mode diagram of an artificial plasmon structure according to an exemplary embodiment.

[0023] FIG. 3 is a diagram showing evolutionary spectra of artificial plasmon structures with different inner diameters according to an exemplary embodiment.

[0024] FIG. 4 is a diagram showing a field enhancement contrast spectrum after utilizing an artificial plasmon structure according to an exemplary embodiment.

[0025] FIG5 is a diagram showing the relationship between the measured phase difference and the incident angle of the incoming wave of a direction finding device based on a coupled detuned artificial surface plasmon according to an exemplary embodiment. DETAILED DESCRIPTION

[0026] Exemplary embodiments are described in detail herein, with examples illustrated in the accompanying drawings. When the following description refers to the drawings, identical numerals in different drawings represent identical or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with this application.

[0027] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. As used in this application and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0028] It should be understood that although the terms first, second, third, etc. may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0029] The present application provides a direction-finding device based on coupled-detuned artificial surface plasmons. As shown in FIG1 , the device includes a dielectric substrate and two metal discs with grooves uniformly cut from the edge toward the center and having different materials or sizes. The two grooved metal discs have different size parameters or materials, thereby forming a first artificial surface plasmon resonator DSPR1 and a second artificial surface plasmon resonator DSPR2, respectively, that support different resonant frequencies. The lower surface of the dielectric substrate is plated with metal, and the two artificial plasmon resonators are spaced apart on the upper surface of the dielectric substrate, with the center of the dielectric substrate as the center of symmetry and the diagonal line of the dielectric substrate as the axis, to form a coupled-detuned artificial surface plasmon structure.

[0030] It should be noted that the different sizes of the two metal discs are specifically different outer radius, inner radius or disc thickness, where the outer radius is the radius of the metal disc and the inner radius is the radius of the ungrooved portion of the metal disc.

[0031] The following description is made in conjunction with an embodiment in which the frequency of the incoming signal is 3.67 GHz.

[0032] Specifically, the two metal discs are grooved evenly from the edge to the center, and their inner diameters are r1 and r2, their outer diameters are R1 and R2, and their thicknesses are h. c1 and h c2 , the number of grooves is N, the duty ratio 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 be made of different materials, and the closest distance between the edges 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 maintain the composition structure of the dielectric substrate and the metal disc to support the surface plasmon resonance mode, for example, it can be polytetrafluoroethylene F4BTMS220, the dielectric constant of the dielectric substrate material 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 copper plating thickness is h b In specific implementations, the above materials and parameter selections can be adjusted appropriately according to needs. During the adjustment, it is necessary to maintain the structure of the dielectric substrate and the metal disc to support the surface plasmon resonance mode. In this exemplary embodiment, for 3.67GHz electromagnetic wave direction finding, the metal disc material is copper, the number of grooves N = 60, the duty cycle A = 50% (that is, within one groove cycle, the groove space: non-grooved space = 1:1); the outer diameter R1 = R2 = R = 12mm, and the thickness h c1 =h c2 =h c=0.0175mm, DSPR1 inner diameter r1 = 6mm, DSPR2 inner diameter r2 = 6.2mm; the closest distance between the edge of DSPR1 and the edge of DSPR2 is d = 10mm. The dielectric substrate material is polytetrafluoroethylene F4BTMS220, with a dielectric constant ε = 2.2, and the bottom metal coating material is copper. The dielectric substrate length L = 80mm, thickness h d =2mm, the bottom copper plating thickness is h b =0.0175mm.

[0033] It should be noted that how to adjust materials and parameters according to specific needs is a conventional technical means in this field and will not be elaborated here.

[0034] As shown in Figure 2, the spectrum diagram of the first artificial surface plasmon and the second artificial surface plasmon in an embodiment of the present invention and the artificial localized surface plasmon resonance mode they support are shown. As can be seen from the figure, due to the different groove depths, the resonance peak positions of the first and second artificial surface plasmon structures with inner circle radii of 6mm and 6.2mm are ω1 = 3.655GHz and ω2 = 3.685GHz respectively, indicating a resonant frequency detuning. The central resonant frequency of the coupled detuned artificial surface plasmon system they constitute is ω0 = (ω1 + ω2) / 2 = 3.67GHz; and both artificial surface plasmon structures support dipole resonance modes at the resonance peaks.

[0035] It should be noted that for incoming signals of other frequencies, by adjusting the parameters of the two artificial surface plasmon structures, such as the inner radius, outer radius, thickness, or material, the central resonant frequency of the coupled detuned artificial surface plasmon system can be adjusted to align with the incoming signal frequency, thus providing a platform for electromagnetic wave direction finding across different frequency bands. Taking the inner radius r as an example, Figure 3 shows the evolution of the spectrum of artificial surface plasmon resonators with different inner radii. This figure confirms that by adjusting the artificial surface plasmon parameters, direction finding can be achieved for incoming signals of other frequencies.

[0036] Figure 4 shows the field intensity spectrum obtained from experimental detection under far-field illumination from a horn antenna. As can be seen, under identical measurement conditions, the artificial surface plasmon structure achieves an approximately 33-fold increase in field intensity, significantly improving direction-finding sensitivity.

[0037] As shown in Figure 5, the relationship between the phase difference and the incident angle of the 3.67GHz wave measured by the coupled detuned artificial surface plasmon direction finding device and the uncoupled antenna direction finding device is shown. As can be seen from the figure, the phase difference measured by the coupled detuned artificial surface plasmon lateral device and the incident angle of the wave show a one-to-one monotonically increasing relationship; and compared with the measurement results of the independent antenna direction finding device (phase difference range of 0° to 130.4°), the measured phase difference range is significantly widened (phase difference range of 0° to 159.4°). Therefore, it is shown that the direction finding device based on coupled detuned artificial surface plasmon can achieve full-range direction finding with an incoming wave direction of 0° to 90°, and its enhanced phase difference can further improve the direction finding accuracy.

[0038] It should be noted that in practice, the direction-finding device must be fixed, and identical probes must be placed at points A and B (as shown in Figure 1). These probes are then connected to a phase-finding circuit. When finding the direction of an incoming wave, the probes measure the electric field phase, which is then transmitted to the direction-finding circuit to calculate the difference in electric field phase between points A and B, thereby determining the angle of incidence of the incoming wave signal.

[0039] When electromagnetic waves are incident at different angles, the two artificial surface plasmon resonators respond to the waves, presenting artificial localized surface plasmon resonance modes with different phases. Direction measurement can be performed based on the correspondence between their phase difference and the incident angle of the waves.

[0040] Those skilled in the art will readily conceive of other embodiments of the present application after considering the specification and practicing the contents disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of this application and include common knowledge or customary techniques in the art that are not disclosed in this application.

[0041] It will be understood that the present application is not limited to the exact construction that has been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof.

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 uniformly cut from the edge to the center and having different sizes or materials; The two metal discs are formed by different sizes or materials to form a first artificial surface plasmon resonator DSPR1 and a second artificial surface plasmon resonator DSPR2 supporting different resonant frequencies respectively; The lower surface of the dielectric substrate is plated with metal, and two artificial surface plasmon resonators are 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.

2. A direction finding device based on coupled detuned artificial surface plasmons according to claim 1, characterized in that: The two metal discs have different sizes, specifically different outer radius, inner radius or thickness of the discs, wherein the outer radius is the radius of the metal disc and the inner radius is the radius of the ungrooved portion 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, characterized in that: 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.

5. The direction-finding device based on coupled-detuned artificial surface plasmon according to claim 1, characterized in that: The two artificial surface plasmon resonators respond to artificial localized surface plasmon resonance modes with different phase differences according to the directions of incoming waves.

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