L-band dielectric lens and lens antenna for satellite multi-beam communication

Abstract

The application discloses an L-band dielectric lens and a lens antenna for satellite multi-beam communication and belongs to the technical field of communication.The lens designed by the application is a cylindrical flat plate lens and is composed of a plurality of concentric circular ring layers.Each circular ring layer is arranged in a circular ring shape around the center by fan ring structure units of the same configuration, and the dielectric constant of each layer gradually decreases from the center to the edge.Compared with a traditional flat plate lens after optical transformation, the lens can realize miniaturization without complex optical transformation, has a simple structure, the lens thickness can be adjusted at will, and the lens can be quickly prepared by using 3D printing.The fan ring structure unit combining the "Y" shape and the circular perforation shape is used as an equivalent dielectric constant model, so that the dielectric constant is closer to the ideal gradient change, and the lens is closer to the ideal effect, so that the lens can be used in the lens antenna, and the working performance is further improved.

Description

Technical Field

[0001] The present invention belongs to the field of communication technologies, and more specifically, relates to an L-band dielectric lens and a lens antenna for satellite multi-beam communication. Background Art

[0002] With the continuous development of radar and satellite systems, lens antennas with high gain and wide-angle beam scanning applied in the L-band have received extensive attention. Among different types of lenses, Maxwell fisheye lenses, Eaton lenses, and Luneburg lenses are all dielectric constant gradient lenses, which can achieve good focusing performance and a relatively wide beam scanning range. However, a common feature of them is that their shapes are all spherical. To overcome this limitation, people use complex mathematical methods such as transformation optics or quasi-conformal transformation optics to transform the spherical lens into a flat lens. However, after the optical transformation, the dielectric constant of the lens is required to be anisotropic, and the quasi-conformal transformation requires a large amount of complex and cumbersome mathematical calculations. At the same time, since the lenses in the L-band often have relatively large sizes, although the volume of the lens after the optical transformation becomes smaller, materials with a relatively high dielectric constant are needed to meet the preparation requirements, and the requirements for material properties are relatively high, which limits their applications. Summary of the Invention

[0003] Aiming at the defects and improvement requirements of the prior art, the present invention provides an L-band dielectric lens and a lens antenna for satellite multi-beam communication, aiming to solve the technical problem that the material properties required for the existing L-band dielectric lenses are relatively high and their applications are limited.

[0004] To achieve the above object, in a first aspect, the present invention provides an L-band dielectric lens for satellite multi-beam communication. The dielectric lens is a cylindrical flat lens, and is divided into several concentric circular ring layers along the center of the dielectric lens to the edge according to a gradient distribution with the equivalent dielectric constant gradually decreasing. Each layer is composed of the same number of fan-shaped structural units arranged around the center to form a ring; the equivalent dielectric constant of each fan-shaped structural unit changes with the filling volume ratio of the medium to air in the fan-shaped structural unit.

[0005] Further, the fan-shaped structural unit near the edge of the dielectric lens is a "Y"-shaped fan-shaped structural unit, where the medium fills to form a "Y" shape and the rest is filled with air; the fan-shaped structural unit near the center of the dielectric lens is a fan-shaped structural unit with a circular perforation.

[0006] Further, the fan-shaped structural unit near the edge of the dielectric lens is a fan-shaped structural unit with a "hui" shape with a perforation in the middle; the fan-shaped structural unit near the center of the dielectric lens is a fan-shaped structural unit with a circular perforation.

[0007] Further, the distribution of the equivalent dielectric constant of each concentric circular ring layer is determined according to the following formula:

[0008] ε(r)=ε0sech 2 (αr)

[0009] Where ε(r) represents the equivalent dielectric constant of the concentric ring layer corresponding to radius r, ε0 is the center dielectric constant of the dielectric lens, α=2πp / w is the gradient parameter, w is the thickness of the dielectric lens, p is a constant, sech(*)=1 / cosh(*), and cosh(*) represents the hyperbolic cosine function.

[0010] Furthermore, the volume fraction of the medium filling in the fan-shaped structural unit of the concentric ring layer corresponding to radius r is determined according to the following formula:

[0011] ε(r)=ε air (1-c)+ε dielectric c

[0012] Where, ε air and ε dielectric Let r represent the dielectric constants of air and medium in the fan-shaped structural unit of the concentric ring layer corresponding to radius r, and c be the volume fraction of the medium.

[0013] Furthermore, the diameter of the dielectric lens is 2 to 10 wavelengths, and the width of each concentric ring layer is 1 / 15 to 1 / 8 wavelength, wherein the wavelength is any wavelength corresponding to a frequency of 1 to 2 GHz.

[0014] To achieve the above objectives, in a second aspect, the present invention provides a lens antenna, comprising a plurality of radiating elements and a dielectric lens as described in the first aspect, wherein the plurality of radiating elements are distributed circumferentially along the dielectric lens.

[0015] In summary, the above-described technical solutions conceived in this invention can achieve the following beneficial effects:

[0016] (1) The dielectric lens proposed in this invention is a cylindrical flat lens, divided into several concentric ring layers with a gradient distribution from the center to the edge according to a gradually decreasing equivalent dielectric constant. Unlike existing technologies, the structural units constituting the concentric ring layers in this invention are identical and regular fan-shaped ring structures. The equivalent dielectric constant of the fan-shaped ring structure unit can be changed by altering the ratio of the dielectric to air volume. Compared to other irregular structures, the uniform shape of the fan-shaped ring structure units in this invention simplifies processing, allowing for rapid fabrication using 3D printing. Compared to traditional flat lenses after optical transformation, miniaturization can be achieved without complex optical transformations, resulting in a simpler structure and adjustable lens thickness.

[0017] (2) The present invention uses a "Y"-shaped fan-shaped ring structure unit as the configuration of the edge part of the dielectric lens, and a circular perforated fan-shaped ring structure unit as the configuration of the central part of the dielectric lens, jointly constituting an equivalent dielectric constant model of the dielectric lens, so that the equivalent dielectric constant can be closer to the ideal gradient change, and the dielectric lens is closer to the ideal effect.

[0018] (3) After the feed is loaded with the dielectric lens, the spherical wave can be transformed into a plane wave, and the gain is significantly improved, and beam scanning can be achieved. Brief Description of the Drawings

[0019] Figure 1 It is the front view of an L-band dielectric lens for satellite multi-beam communication provided by Embodiment 1 of the present invention;

[0020] Figure 2 It is the side sectional view of an L-band dielectric lens for satellite multi-beam communication provided by Embodiment 1 of the present invention;

[0021] Figure 3-1 、 Figure 3-2 and Figure 3-3 They are respectively the schematic diagrams of the "Y"-shaped, circular perforated, and "return" - shaped fan-shaped ring structure units with a middle perforation of an L-band dielectric lens for satellite multi-beam communication provided by Embodiment 1 of the present invention;

[0022] Figure 4 It is the relative dielectric constant distribution diagram of the dielectric lens provided by Embodiment 2 of the present invention;

[0023] Figure 5 It is the two-dimensional electric field distribution diagram of the dielectric lens provided by Embodiment 2 of the present invention;

[0024] Figure 6 It is the gain comparison diagram of the dielectric lens before and after loading the feed provided by Embodiment 2 of the present invention;

[0025] Figure 7 It is the beam scanning diagram of the dielectric lens provided by Embodiment 2 of the present invention;

[0026] Figure 8 It is the relationship diagram between the y-direction displacement and the beam deflection angle of the dielectric lens provided by Embodiment 2 of the present invention. Detailed Embodiment

[0027] In order to make the purpose, technical solution and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] In the present invention, terms such as "first", "second", etc. (if any) in the present invention and the accompanying drawings are used to distinguish similar objects and do not necessarily describe a specific order or sequence.

[0029] Example 1

[0030] The present invention provides an L-band dielectric lens for satellite multi-beam communication. The dielectric lens is a cylindrical flat lens, and is divided into several concentric circular ring layers along the center of the dielectric lens to the edge according to a gradient distribution with gradually decreasing equivalent dielectric constant. Each layer is composed of the same number of fan-shaped structural units arranged around the center to form a ring; the equivalent dielectric constant of each fan-shaped structural unit changes with the ratio of the filling volume of the medium and air in the fan-shaped structural unit.

[0031] In this embodiment, the front view and side cross-sectional view of the dielectric lens are as shown in Figure 1 and Figure 2 . Among them, the dielectric constant of the outer ring near the edge is smaller, and the "Y"-shaped or "return"-shaped fan-shaped structural unit with a higher air filling rate can be used as the basic configuration of the outer ring, and the structural width gradually increases from the outside to the inside. And the dielectric constant of the inner ring near the center is larger and changes more gently, and the volume fraction of the dielectric material in the ring-shaped structural unit is relatively high. Therefore, a circular perforated fan-shaped structural unit configuration can be adopted, and the aperture gradually decreases from the outside to the inside. The advantage of doing this is to make the dielectric constant closer to the ideal gradient change, and the lens is closer to the ideal change law. Among them, the "Y"-shaped, circular perforated and "return"-shaped fan-shaped structural units with intermediate perforations are as shown in Figure 3-1 , Figure 3-2 and Figure 3-3 . The dotted part is the dielectric material, and the blank part is air filling. Figure 3-1 In Figure 3-2 , a represents the width of the "Y"-shaped fan-shaped structural unit, that is, the width of the dielectric material.

[0032] Further, the required equivalent dielectric constant of each layer can be calculated through the equivalent dielectric constant distribution formula and the calculation method of the equivalent dielectric constant of the designed dielectric lens. By changing the sizes of the "Y"-shaped and circular perforated fan-shaped structural units, the design requirements of the ideal lens can be better met.

[0033] Specifically, the equivalent dielectric constant distribution of each concentric circular ring layer is determined according to the following formula:

[0034] ε(r) = n 2 (r) = ε0sech 2 (αr)

[0035] Where ε(r) represents the equivalent dielectric constant of the concentric ring layer corresponding to radius r, n(r) represents the effective refractive index, ε0 is the center dielectric constant of the dielectric lens, α=2πp / w is the gradient parameter, w is the thickness of the dielectric lens, p is a constant, sech(*)=1 / cosh(*), and cosh(*) represents the hyperbolic cosine function.

[0036] The volume fraction of the medium filling material in the fan-shaped structural unit of the concentric ring layer corresponding to radius r is determined by the following formula:

[0037] ε(r)=ε air (1-c)+ε dielectric c

[0038] Where, ε air and ε dielectric Let r represent the dielectric constants of air and medium in the fan-shaped structural unit of the concentric ring layer corresponding to radius r, and c be the volume fraction of the medium.

[0039] Thus, by keeping the dielectric constant distribution of the dielectric lens constant and ensuring that the ratio of lens thickness w to constant p remains constant, lenses of different thicknesses can be designed, and the 3D printing requirements of materials with various dielectric constants can also be met.

[0040] Example 2

[0041] All dimensions in this embodiment correspond to an L-band 1.1GHz design. For example... Figure 1 A dielectric material with a dielectric constant of 2.8 is used, with a radius of 500 mm and a thickness of 100 mm. According to the formula, its dielectric constant needs to gradually change from 1.55 to 2.8 along the radial direction. Through discretization and layering, the lens region is divided into 12 equal layers radially from the outside in, corresponding to layers 1 to 12, with their corresponding relative dielectric constants as follows: Figure 4 The dielectric constants of each layer and the dimensions of the unit structure are shown in Tables 1 and 2. Then, a 10dB standard waveguide horn antenna with a frequency range of 0.96GHz to 1.45GHz was designed as a feed source and placed on the lens focal length (approximately 1000mm) plane. Figure 5 The diagram shows a two-dimensional electric field distribution. It can be seen that the spherical wave excited by the feed source becomes a plane wave after passing through the lens. Figure 6 This is a gain comparison chart of the horn antenna and the lens antenna. Taking 1.1GHz as an example, when a lens is added, the lens antenna achieves a maximum gain of 17.07dBi, a gain increase of 5.3dB, demonstrating a significant gain improvement. Furthermore, beam adjustment can be achieved by shifting the feed source within the lens's focal length (approximately 1000mm) plane. (Using 1.1GHz as an example...) Figure 7 and Figure 8This is a beam scan diagram and corresponding beam deflection angles when translated 0–300 mm along the y-direction of the constant focal length plane. It can be seen that after translating 300 mm along the y-direction, the gain is 16.8 dBi, and the beam can be deflected by 13°. Considering the structural symmetry, the designed gradient dielectric lens antenna can achieve a beam scan of ±13° with a gain drop ≤0.27 dB.

[0042] Table 1. Structural parameters of the "Y"-shaped fan-shaped ring structure unit.

[0043]

[0044] Table 2 Structural parameters of circular perforated fan-shaped structural units

[0045]

[0046] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An L-band dielectric lens for satellite multi-beam communication, characterized in that, The dielectric lens is a cylindrical flat plate lens, and is divided into several concentric ring layers with a gradient distribution from the center to the edge of the dielectric lens according to the equivalent dielectric constant gradually decreasing. Each layer consists of the same number of fan-shaped structural units arranged around the center to form a ring. The equivalent dielectric constant of each fan-shaped structural unit varies with the ratio of the filling volume of the dielectric to the air in the fan-shaped structural unit. The fan-shaped annular structural unit near the edge of the dielectric lens is a "Y"-shaped fan-shaped annular structural unit, wherein the dielectric fills to form a "Y" shape, and the rest is filled with air; the fan-shaped annular structural unit near the center of the dielectric lens is a circular perforated fan-shaped annular structural unit. The equivalent dielectric constant distribution of each concentric ring layer is determined according to the following formula: ； in, Indicates radius as The equivalent dielectric constant of the corresponding concentric ring layer, The dielectric constant is the center dielectric constant of the dielectric lens. For gradient parameters, The thickness of the dielectric lens, It is a constant. , Represents the hyperbolic cosine function; radius is The volume fraction of the medium filling in the corresponding concentric ring layer fan-shaped structural unit is determined according to the following formula: ； in, and They represent radii of The dielectric constants of air and dielectric in the corresponding concentric ring layer fan-shaped structural unit. This refers to the volume fraction of the medium. The diameter of the dielectric lens is 2 to 10 wavelengths, and the width of each concentric ring layer is 1 / 15 to 1 / 8 wavelength, wherein the wavelength is any wavelength corresponding to a frequency of 1 to 2 GHz.

2. A lens antenna, characterized in that, It includes multiple radiating elements and a dielectric lens as described in claim 1, wherein the multiple radiating elements are distributed circumferentially along the dielectric lens.

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