Spherical designer electromagnetic surface plasmon open resonator

Abstract

A spherical designer electromagnetic surface plasmon open resonator is provided. The open resonator includes a resonator inner core and a resonator outer shell. The resonator inner core is located in an inner center of the resonator outer shell, and the resonator inner core and the resonator outer shell are coaxial. The disclosure provides a device that implements the superscattering function for incident waves in all incident directions and in all polarization directions, and a spherical open resonator is implemented. The scattering cross section of the disclosure can be more than five times greater than that of a metal sphere of the same size, and the operating frequency can be flexibly designed. By utilizing the characteristic that the scattering cross section of the spherical designer electromagnetic surface plasmon resonator is much greater than its own geometric cross section, the electromagnetic super-scattering device can be implemented.

Claims

1. A spherical designer electromagnetic surface plasmon open resonator, wherein comprising a resonator inner core and a resonator outer shell, wherein the resonator inner core is located at a central interior of the resonator outer shell, and the resonator inner core and the resonator outer shell are coaxial, wherein the resonator inner core is a sphere, the resonator outer shell comprises a plurality of fan-ring-shaped strip-shaped bars, one end of each strip-shaped bar in a length direction is an inner arc bottom surface of the strip-shaped bar, the other end of each strip-shaped bar in the length direction is an outer arc bottom surface of the strip-shaped bar, the strip-shaped bars are evenly distributed on a spherical surface of the resonator inner core in directions of an azimuthal angle and a polar angle with a duty cycle , the inner arc bottom surfaces of the strip-shaped bars are evenly spaced in an array, distributed on the spherical surface of the resonator inner core as a whole, the outer arc bottom surface of each strip-shaped bar is away from the spherical surface of the resonator inner core, and the length direction of each strip-shaped bar is the same as a radius direction of the resonator inner core.

2. The spherical designer electromagnetic surface plasmon open resonator according to claim 1, wherein the resonator inner core and the resonator outer shell are specifically made of metal or resin materials.

3. The spherical designer electromagnetic surface plasmon open resonator according to claim 2, wherein when the resonator inner core and the resonator outer shell are made of resin materials, a surface of the open resonator is evenly covered with metal powder.

4. The spherical designer electromagnetic surface plasmon open resonator according to claim 1, wherein the resonator outer shell has an effective negative refractive index specifically as follows: $n=\sqrt{{}_r},$ wherein .sub.r is the effective negative permittivity of the resonator inner core with a radius r of the resonator.

5. The spherical designer electromagnetic surface plasmon open resonator according to claim 4, wherein the negative permittivity of the resonator inner core with the radius r of the resonator is as follows: ${}_r=1-\frac{f_p^2}{f^2},$ wherein f is the operating frequency of the resonator, and f.sub.p is a designer plasma frequency of the resonator.

6. The spherical designer electromagnetic surface plasmon open resonator according to claim 1, wherein the open resonator has a scattering crosssection that is more than five times a geometric crosssection of the open resonator itself for linearly polarized electromagnetic waves incident from any direction.

7. Application of the open resonator according to claim 1, wherein the open resonator is used in application of a spherical superscattering device.

8. The application of the open resonator according to claim 1, wherein the open resonator is used in application of a spherical wide-aperture antenna.

9. A method of applying the open resonator according to claim 1, wherein the open resonator is used for application of scattering linearly polarized electromagnetic waves incident from any direction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an overall structural view of an electromagnetic wave superscattering device of the disclosure.

(2) FIG. 2 is a cross-sectional view of the electromagnetic wave superscattering device of the disclosure.

(3) FIG. 3A is a top view of the electromagnetic wave superscattering device of the disclosure.

(4) FIG. 3B is a cross-sectional top view of the electromagnetic wave superscattering device of the disclosure.

(5) FIG. 4A is a front view of the electromagnetic wave superscattering device of the disclosure.

(6) FIG. 4B is a cross-sectional front view of the electromagnetic wave superscattering device of the disclosure.

(7) FIG. 5 is a graphic comparison of the total scattering cross sections between the electromagnetic wave superscattering device of the invention and a standard metal sphere of the same size.

(8) FIG. 6A is the E-plane pattern diagram at the first resonance peak of 0.9 GHz.

(9) FIG. 6B is the H-plane pattern diagram at the first resonance peak of 0.9 GHz.

(10) FIG. 7A is the E-plane pattern diagram at the second resonance peak of 1.35 GHz.

(11) FIG. 7B is the H-plane pattern diagram at the second resonance peak of 1.35 GHz.

(12) FIG. 8A is the E-plane pattern diagram at the third resonance peak of 1.53 GHz.

(13) FIG. 8B is the H-plane pattern diagram at the third resonance peak of 1.53 GHz.

(14) FIG. 9 is a schematic comparison diagram of the radiation efficiency between the spherical wide-aperture antenna of the disclosure (solid line) and the standard metal sphere of the same size (dashed line).

(15) In the figure: 1: resonator inner core, and 2: resonator outer shell.

DESCRIPTION OF THE EMBODIMENTS

(16) The disclosure is further described in detail together with accompanying drawings and specific embodiments in the following paragraphs.

(17) As shown in FIG. 1 and FIG. 2, a spherical designer electromagnetic surface plasmon open resonator of the disclosure includes a resonator inner core 1 and a resonator outer shell 2. The resonator inner core 1 is located the internal center of the resonator shell 2, with both the resonator core and shell sharing the same axis. The open resonator has a scattering cross section over five times greater than its own geometric cross section for linearly polarized electromagnetic waves incident from any direction. The open resonator may be used for spherical superscattering device and a small spherical wide-aperture antenna. The open resonator scatters linearly polarized electromagnetic waves incident from any direction.

(18) The resonator inner core 1 is a sphere, and the resonator outer shell 2 includes a plurality of fan-ring-shaped strip-shaped bars. One end of each strip-shaped bar in the length direction is an inner arc bottom surface of the strip-shaped bar, and the other end of each strip-shaped bar in the length direction is an outer arc bottom surface of the strip-shaped bar. The strip-shaped bars are evenly distributed on a spherical surface of the resonator inner core 1 in directions of an azimuthal angle and a polar angle with a duty ratio . The inner arc bottom surfaces of the strip-shaped bars are evenly spaced in an array, distributed on the spherical surface of the resonator inner core 1, and connected to the resonator inner core 1 as a whole. The outer arc bottom surface of each strip-shaped bar is away from the spherical surface of the resonator inner core 1, and the length direction of each strip-shaped bar is the same as a radius direction of the resonator inner core 1.

(19) The resonator inner core 1 and the resonator outer shell 2 are specifically made of metal or resin materials through 3D printing, forming a single integrated structure. The metals mentioned for this purpose include aluminum or stainless steel, which are commonly used for their conductive properties and structural integrity. When the resonator inner core 1 and the resonator outer shell 2 are made of resin materials, a surface of the open resonator is evenly covered with metal powder, and the metal powder can be copper, aluminum, gold, or stainless steel, etc.

(20) The resonator outer shell 2 has an effective negative refractive index n, specifically as follows:

(21) $n=\sqrt{{}_r},$ where .sub.r is the effective negative permittivity of the resonator outer shell 2 with an outer radius r of the resonator, which can be described by Lorentz-Drude model of electrical conductivity.

(22) The specific negative permittivity of the resonator outer shell 2 with the radius r of the resonator is as follows:

(23) ${}_r=1-\frac{f_p^2}{f^2},$ where f is the operating frequency of the resonator, and f.sub.p is the effective plasma frequency of the resonator.

(24) The disclosure relates to a spherical designer electromagnetic surface plasmon open resonator, and in the disclosure, spectral degeneracy of the designer electromagnetic surface plasmon resonance modes is mainly used to achieve a scattering cross section that far exceeds the geometric cross section, and a high receiving aperture antenna is implemented in combination with infeed technology. As shown in FIG. 1, it is an appearance of the open electromagnetic resonator provided by the disclosure. The resonator is placed at the origin of a coordinate system. An angle between a point on a spherical surface of the resonator and a xOz surface is an azimuth angle , and an angle between the point on the spherical surface of the resonator and a z-axis is a polar angle . As shown in FIG. 2, it is a three-dimensional cross-sectional view of the open electromagnetic resonator provided by the disclosure. The open resonator mainly includes a resonator inner core 1 and a resonator outer shell 2. The resonator outer shell 2 is formed by 18 rows of metal square bars arranged in a direction of the polar angle and 36 rows of metal square bars arranged in a direction of the azimuth angle with a height h, and the metal square bars are evenly distributed in the directions of the azimuth angle and the polar angle with a duty ratio =0.5. The metal square bars are all the same in the direction of the azimuth angle , and the metal square bars change gradually in the direction of the polar angle . As shown in FIG. 3A and FIG. 3B, a left side view of the open electromagnetic resonator and a cross-sectional view of the open electromagnetic resonator with the azimuth angle =0 are shown. A spherical center angle corresponding to the square bars in the direction of the polar angle is 5. As shown in FIG. 4A and FIG. 4B, the left side view of the open electromagnetic resonator and the cross-sectional view of the open electromagnetic resonator with the polar angle =90 are shown, and the spherical center angle corresponding to the square bars in the direction of the azimuth angle is 5.

(25) As shown in FIG. 5, the figure shows comparison between scattering cross section of: (1) an electromagnetic superscattering device of the disclosure with parameters r=15 mm h=35 mm, and =0.5, (2) a standard metal sphere with a same outer radius R=50 mm and (3) their geometric cross section in a frequency range from 0.65 GHz to 1.65 GHz. At 0.9 GHZ, 1.35 GHz, and 1.53 GHz in the figure, the scattering cross section (solid line) of the spherical designer electromagnetic surface plasmon open resonator and the superscattering device is significantly larger than both the geometric cross section (dotted line) and the scattering cross section (dashed line) of a standard metal sphere of the same size, achieving an enhanced scattering effect.

(26) As shown in FIG. 6A, FIG. 6B, FIG. 7A, FIG. 7B, FIG. 8A, and FIG. 8B, at 0.9 GHz, 1.35 GHZ, and 1.53 GHZ, the scattering width (solid line) of the spherical designer electromagnetic surface plasmon open resonator, and the superscattering device in both the E-plane and H-plane is much greater than the scattering cross section (dashed line) of a standard metal sphere of the same size, indicating that the spherical designer electromagnetic surface plasmon open resonator and the superscattering device can achieve enhanced scattering in all directions.

(27) As shown in FIG. 9, by connecting a feed to the surface of the spherical designer electromagnetic surface plasmon open resonator and optimizing the feeding, a wide-aperture antenna can be realized. Compared to a standard metal sphere connected to the infeed (dashed line), the wide-aperture antenna based on the spherical designer electromagnetic surface plasmon open resonator may achieve more than 10 times the radiation efficiency at resonance peaks. According to the reciprocity principle of antenna, this resonator can improve antenna sensitivity when being used as a receiving antenna.

(28) The aforementioned embodiments are merely preferred solutions of the disclosure, but the embodiments are not intended to limit the disclosure. A person having ordinary skill in the art can also make various changes and modifications without departing from the spirit and scope of the disclosure. Therefore, any technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the disclosure.