RU2785014C1 - Method for using s-elements to convert a normally incident uhf wave into surface scattering in the azimuthal plane - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: area of application: invention relates to the field of radio engineering, more specifically, to systems for frequency selective energy concentration in the ultrahigh frequency (UHF) range, and can be used for auxiliary power supply systems. Substance: according to the claimed method, S-elements are used to convert a normally incident UHF wave into surface scattering in the azimuthal plane based on a planar metamaterial capable of being located conformally on rectilinear and curvilinear surfaces. Herewith, a metamaterial based on a composition of a planar dielectric container and 2 matrices made of conductive S-shaped strip elements located on the external surfaces thereof is used as a concentrating volume. The S-shaped elements on the upper and lower surfaces of the container have the same shape and mirror each other. The distance between adjacent S-shaped elements is comparable with the wavelength of incident UHF emission, and the linear dimensions thereof are significantly smaller than said wavelength. Such a metamaterial provides a possibility, at a preset frequency (number of discrete frequencies), of converting normally (obliquely) incident UHF emission into re-emission inside the layer of metamaterial and thereby accumulating energy inside the layer.

EFFECT: concentration of UHF energy and further use thereof for electricity supply.

1 cl, 2 dwg

Description

The invention relates to the field of radio engineering, and more specifically to systems for frequency selective concentration of energy in the microwave range, can be used for auxiliary power supply systems.

Known patent US 4340031A [1], which is considered as a concentrating device collector with a concave paraboloid reflective surface. The disadvantages of this device: not fulfilling the properties of the planarity of the hub and the impossibility of its conformal placement on curved surfaces.

A device for absorbing electromagnetic waves is known, described in patent RU 2125327 C1 [2]. It is a non-uniform surface in all directions and consists of capacitive and inductive elements alternating among themselves in all directions of this surface. The disadvantages of this device: failure to ensure the selectivity of the absorption of electromagnetic waves, the bulkiness of the design.

A similar device is known, described in patent RU 2169952 C1 [3], for absorbing electromagnetic radiation, consisting of a ferrite substrate and a matching dielectric layer deposited on it with a carbon filler. The disadvantages of this device: failure to ensure the selectivity of the absorption of electromagnetic waves.

The closest in technical essence to the claimed is a selective coating for protection against electromagnetic radiation, described in patent RU 2236731 C1 [4]. It consists of a single dielectric layer, on both surfaces of which strip metal chiral elements are also deposited. However, at the resonant frequency of such a coating, total reflection is observed in the absence of the passage of an electromagnetic wave, and the device cannot be used as a frequency-selective concentrator of microwave energy.

The problem to be solved by the claimed invention is to develop a method of using S - elements to convert a normally incident microwave wave into surface scattering in the azimuthal plane using a planar metamaterial that can be conformally located on straight and curved surfaces.

The technical result is achieved by using S-shaped resonant strip elements in the structure of the metamaterial, which are evenly placed and equally oriented on the surfaces of the dielectric container of the metamaterial, as well as by the existence of spatial dispersion in the metamaterial. Such a metamaterial allows, at a predetermined frequency (a number of discrete frequencies), to convert normally (obliquely) incident microwave radiation into reradiation inside the metamaterial layer.

A metamaterial is a combination of a dielectric container and conductive microelements placed on its surfaces. To solve the problem of frequency selective concentration of microwave energy, the so-called chiral metamaterial is used, in which the conductive elements have a mirror asymmetric shape, that is, they do not coincide with their reflection in a flat mirror. S-shaped strip microelements were used as mirror elements. The dimensions of microelements are much smaller than the wavelength of the incident microwave radiation, and the distance between them is commensurate with the wavelength. The fundamental thing for creating a frequency-selective microwave energy concentrator is that the metamaterial as a whole has the property of chirality. To do this, S-shaped elements must be placed at the same distance from each other, and their geometric axes must be oriented in the same way. With uniform placement of S-elements inside the dielectric container, the metamaterial will also have the property of spatial dispersion.

The inventive method makes it possible to avoid using large microwave lenses and mirrors in the development of a frequency selective microwave energy concentrator, and also to achieve the effect of concentrating microwave energy in a fully planar structure that can be placed on straight and curved surfaces.

For a better understanding of the essence of the claimed invention, further explanations are given with the involvement of graphic materials.

In FIG. 1a shows the general structure of a planar chiral metamaterial located on a flat surface and used to create a frequency selective microwave energy concentrator. The metamaterial consists of a dielectric container (substrate) k.1, which serves as a volume for the concentration of microwave energy incident at a certain frequency on the metamaterial. The thickness of the container must be greater than the wavelength of the concentrated microwave radiation. On the front surface of the container there is an M.1 matrix of S-shaped strip conductive elements. The elements are located at equal distances from each other and have the same orientation relative to each other. S-shaped elements located on the front surface of the container are right-handed. On the rear surface of the container there is a matrix m.2 of strip conductive S-shaped elements. In this case, the elements have geometric dimensions identical to the elements from the matrix m.1, they are also equally oriented relative to each other, but they have a left-hand shape (that is, they are reflections in a flat mirror of the elements from the matrix m.1). In FIG. 1b shows the general structure of a planar chiral metamaterial located on a curved surface. In FIG. 1, c shows the structure of an S-shaped element, which is described by two geometric parameters - the radius and width of the strip. All elements are resonant, while their resonant frequency is determined by the Thomson formula through the capacitance and inductance of the element (quasi-static approximation).

A plane electromagnetic wave of linear or circular polarization is incident on the considered chiral metamaterial from the outer space at a given frequency at some angle to the “external medium – metamaterial” interface. When an electromagnetic wave is incident on a metamaterial that has the properties of chirality and spatial dispersion, due to the mirror asymmetric shape of the elements, the phenomenon of cross-polarization of the field occurs, that is, components appear in the structures of the electromagnetic field of the reflected and transmitted waves that were absent in the structure of the incident wave. The incident electromagnetic wave induces alternating electric currents on the S-shaped elements of the matrix m.1, which, flowing through the annular sections of the elements, re-radiate the electromagnetic field with all components of the vectors of the electric and magnetic fields (cross-polarization phenomenon). In the general case, inside a dielectric container, an electromagnetic field is formed by a superposition of the fields of two waves with right and left circular polarizations. An electromagnetic wave with orthogonal polarization, incident on the matrix m.2, under the resonance conditions, is reflected back into the metamaterial container. At the same time, the fundamental fact is that the elements in the matrix m. 2, located on the lower surface of the container, are mirror images of the elements from the matrix m.1. Thus, at the resonant frequency, due to the appearance of orthogonal components of the electromagnetic field vectors, the wave is concentrated in the volume of the dielectric container and then propagates inside it due to the phenomenon of total internal reflection (the refractive index of the dielectric container is greater than the refractive indices of the surrounding areas). At the same time, at other frequencies, the electromagnetic wave passes through the metamaterial practically without attenuation.

In FIG. 2 shows an example of the frequency dependences of the reflected and transmitted powers, expressed in dB. As can be seen from figure 2, at frequencies of 5.1 GHz and 8.6 GHz, there is a resonant minimum of the power of an electromagnetic wave transmitted behind the metamaterial with an attenuation of about -40 dB, while the attenuation of the power of the wave reflected from the metamaterial is about -20 dB. Near these frequencies, a frequency-selective concentration of the incident microwave power is observed inside the dielectric container. If frequency selective concentration of microwave energy is required at other frequencies, it is necessary to change the geometric dimensions of the S-shaped elements and the distance between them.

Thus, the effect of frequency selective concentration of microwave energy is achieved by converting a normally (obliquely) incident electromagnetic wave into its propagation inside a dielectric container, while the reflection and transmission of the electromagnetic field in external regions is practically absent. This effect is frequency selective and manifests itself at a predetermined frequency (a number of discrete frequencies) of the incident microwave radiation. The frequency at which the described effect is observed is close to the resonant frequency of the S-shaped elements used in the M.1 and M.2 matrices.

It should be borne in mind that the foregoing description is given to illustrate the claimed invention, therefore, specialists should be clear that various modifications and changes are possible that do not contradict the letter and spirit of the scope of protection requested in this application.

LITERATURE

1. Patent US 4340031A United States Patent, IPC Classificatio G02B5/10. HIGH RATIO SOLAR ENERGY / William P. Niedermeyer, 1024 Mt. Mary Dr., Green Bay, Wis. 54301 USA, - No US06/171,097, priority date 07/22/1980; publication date 07/20/1982.

2. Patent RU 2125327 C1 Russian Federation, IPC classification H01Q 17/00. RADIO ABSORBING COATING AND METHOD FOR ITS MANUFACTURE / Alekseev A.G. and others. Open Joint Stock Company "Scientific Research Institute of Rubber Coatings and Products" (JSC "NIIRPI") (RU), No. 2003112634/09, priority date 24.04.2003; publication date 10.02.2005.

3. Patent RU 2169952 C1 Russian Federation, IPC classification G12B 17/00. DEVICE FOR ABSORPTION OF ELECTROMAGNETIC RADIATION / Romanov A.M. and others. State Enterprise "All-Russian Research Institute of Aviation Materials" (RU), - No. 2000112827/09, priority date 24.05.2000; publication date 27.06.2001.

4. Patent RU 2236731 C1 Russian Federation, IPC classification H01Q 17/00. SELECTIVE COATING FOR PROTECTION AGAINST ELECTROMAGNETIC RADIATION / Neganov V.A. and others. Volga State Academy of Telecommunications and Informatics (RU), - No. 2003109213/09, priority date 04/01/2003; publication date 20.09.2004.

Claims (1)

The method of using S-elements to convert a normally incident microwave wave into surface scattering in the azimuthal plane, based on using a metamaterial based on the composition of a planar dielectric container and 2 matrices of conductive strip S-shaped elements located on its outer surfaces as a concentrating volume surfaces, S-shaped elements on the upper and lower surfaces of the container are identical in shape and are mirror images of each other, the distance between adjacent S-shaped elements is commensurate with the wavelength of the incident microwave radiation, and their linear dimensions are much smaller than it, also instead of S-shaped elements, you can use arbitrary strip conductive elements of a mirror asymmetric shape, and instead of a planar metamaterial container, you can use a flexible curvilinear one.

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