An all-metal spherical lens antenna

Abstract

The present invention relates to an all-metal spherical lens antenna, which includes a spherical metal lens. A plurality of first feed antennas are disposed below the metal lens, each first feed antenna being connected and fixed to a support column within the metal lens via a support frame. The metal lens comprises a plurality of metal plates, the spacing between the metal plates being equal and less than half the wavelength of the highest operating frequency. Each layer of metal plates is parallel to each other, and the parallel metal plates form an air-filled parallel plate waveguide. After the electromagnetic waves from the first feed antennas are transmitted to the metal lens, they propagate along the air gaps between the metal plates. By changing the angle between the metal plates and the first feed antennas, the outgoing phase of the incident electromagnetic waves after passing through the metal lens is adjusted. When the phase error is minimized, high-gain radiation is achieved. The present invention utilizes a combination of metal plates to achieve a spherical metal lens structure. By changing the tilt angle of the metal plates, the phase error is minimized, thereby achieving a high-gain radiation beam.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to an all-metal spherical lens antenna. Background Art

[0002] In modern communications and radar systems, high-gain, broadband, and multi-beam antenna technology is crucial for improving system performance, increasing coverage, and meeting diverse application requirements. With the rapid development of wireless communications, the requirements for antenna performance are becoming increasingly stringent. While traditional antenna systems, such as parabolic antennas, phased array antennas, and lens antennas, meet the requirements for high gain and directional radiation to a certain extent, they still have limitations in terms of bandwidth, coverage, and structural complexity.

[0003] Among traditional antenna technologies, Luneburg lenses, dielectric spherical lens antennas, phased array antenna systems, reflectarray antennas, and transmission array antennas have all played important roles. However, they also suffer from several drawbacks in practical applications, primarily due to limitations in material properties, manufacturing processes, and electromagnetic theory and physics. Luneburg lenses require a continuously gradient refractive index from the center to the surface. This continuous refractive index distribution is difficult to achieve accurately in practical manufacturing. This typically requires layering the lens, each layer using a material with a different dielectric constant to approximate the gradient, increasing manufacturing complexity and cost. Furthermore, to achieve high gain and good focusing performance, Luneburg lenses are typically large. This can be impractical in space-constrained or weight-sensitive applications. Achieving a gradient refractive index requires specialized dielectric materials, which can suffer from high dielectric loss, poor temperature stability, or insufficient mechanical strength, compromising lens performance and reliability. These drawbacks arise primarily from the refractive index requirements, engineering challenges, and material limitations. Because dielectric spherical lens antennas have a constant refractive index, they cannot achieve consistent phase compensation for electromagnetic waves of varying frequencies, resulting in a narrow operating bandwidth. A constant refractive index prevents the lens from achieving perfect wavefront matching, resulting in inferior focusing performance compared to lenses with a gradient refractive index, impacting gain and directivity. Furthermore, the significant difference in dielectric constant between the dielectric material and air can cause reflections at the interface, reducing the lens's transmission efficiency. Losses in the dielectric material also result in energy loss. These shortcomings are primarily due to the limitations of a single refractive index, optical principles, and material properties. Phased array antennas require precise amplitude and phase control for a large number of array elements, involving complex electronic control and signal processing components, increasing system complexity and cost. Active phased arrays require independent amplification and phase control components for each element, resulting in high overall power consumption and a disadvantageous energy conservation. When operating in broadband mode, the frequency responses of the array elements and phase shifters may be inconsistent, affecting beamforming accuracy and potentially causing array effects such as increased grating lobes and side lobes, impacting antenna performance. These shortcomings stem primarily from the complex control systems required for flexible beam control, the technical challenges of maintaining consistent electronic performance across a wide bandwidth, and the physical limitations of array antennas. The phase control of transmission array or reflection array antennas usually relies on the resonant unit structure. These units operate near the resonant frequency. The performance drops rapidly outside this frequency range, resulting in a narrow bandwidth. The beam scanning of traditional reflection array antennas requires adjusting the unit phase, which makes the electronic control complex and the scanning angle limited. The efficiency of reflection array antennas is affected by impedance matching, and improper unit design may lead to energy loss. These shortcomings are mainly caused by the strong frequency selectivity of the resonant unit, which makes it difficult to maintain a consistent phase response within a wide frequency band. Achieving wide-angle and fast beam scanning requires a complex phase control system, which increases the technical difficulty, as well as impedance matching problems caused by design complexity.

[0004] In summary, traditional antenna technologies each have limitations in achieving broadband and multi-beam characteristics. Currently, there are no all-metal spherical multi-beam lenses that can achieve 360° beam coverage. These shortcomings are primarily due to material properties, manufacturing process limitations, and the constraints of electromagnetic theory and physics. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a full-metal spherical lens antenna to solve the shortcomings of the prior art.

[0006] The object of the present invention is achieved through the following technical solutions: a full metal spherical lens antenna, which includes a metal lens with a spherical structure, and a plurality of first feed antennas are arranged below the metal lens, each of which is connected and fixed to a support column inside the metal lens through a support frame;

[0007] The metal lens comprises a plurality of metal plates connected together by support columns. The spacing between the metal plates is equal and less than half the wavelength of the highest operating frequency. Each layer of metal plates is parallel to each other. The parallel metal plates form an air-filled parallel plate waveguide. After the electromagnetic wave of the first feed antenna is transmitted to the metal lens, it propagates along the air gap between the metal plates. The transmission mode is the main mode of the parallel plate waveguide. By changing the angle between the metal plate and the first feed antenna, the output phase of the incident electromagnetic wave after passing through the metal lens is adjusted. When the phase error is minimized, high-gain radiation is achieved.

[0008] Multiple first feed antennas are arranged around the outer periphery below the metal lens, and the multiple first feed antennas are arranged at equal intervals to achieve 360° scanning of the first beam in one circle.

[0009] The upper part of the metal plate in the metal lens is removed to achieve miniaturization, and the amount of the removed metal plate is one third to one half of the entire metal plate.

[0010] A plurality of second feed antennas are arranged above the metal lens. The plurality of second feed antennas are connected and fixed to the support column inside the metal lens through a support frame. The plurality of second feed antennas surround the outer periphery above the metal lens, and the plurality of second feed antennas are arranged at equal intervals to achieve 360° scanning of the second beam in one circle.

[0011] There is a corresponding second feed antenna above each first feed antenna, and the first feed antenna and the second feed antenna are in a vertically symmetrical relationship.

[0012] The present invention has the following advantages: an all-metal spherical lens antenna, which realizes a spherical metal lens structure by combining metal flat plates, minimizes phase error by changing the tilt angle of the metal flat plates, and thus realizes a high-gain radiation beam; it can be expanded into a multi-beam lens antenna, and 360-degree beam coverage is achieved by adding multiple feed sources; the all-metal structure avoids the use of dielectric materials, avoids dielectric loss, and improves the radiation efficiency of the antenna; it adopts the main mode TEM mode of parallel flat plates, which theoretically has no cutoff frequency and can work as long as the spacing between the metal plates is less than half the wavelength of the highest operating frequency. Therefore, the lens can theoretically meet ultra-wideband applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the present invention;

[0014] Figure 2 It is a side structural schematic diagram of the present invention;

[0015] Figure 3 Schematic diagram of the dual-feed dual-beam system of the present invention;

[0016] Figure 4 Schematic diagram of electromagnetic wave incident on the upper half plane of the metal lens;

[0017] Figure 5 Schematic diagram of electromagnetic wave incident on the lower half plane of the metal lens;

[0018] Figure 6 Schematic diagram of the simulated electromagnetic distribution

[0019] In the figure: 1-metal lens, 2-first feed antenna, 3-support frame, 4-support column, 5-second feed antenna, 6-first beam, 7-second beam. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present application provided below in conjunction with the drawings is not intended to limit the scope of protection of the present application for which protection is claimed, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application. The present invention is further described below in conjunction with the drawings.

[0021] The present invention specifically relates to an all-metal spherical lens antenna. By designing the tilt angle of the flat plate relative to the feed source, it focuses and controls incident electromagnetic waves, achieving high-gain and broadband radiation characteristics. Due to the symmetry of the spherical structure, multiple feed antennas can be evenly arranged on its surface, forming multiple radiation beams and achieving 360-degree coverage.

[0022] like Figure 1 and Figure 2 As shown, it specifically includes a metal lens with a spherical structure, and a plurality of first feed antennas are arranged below the metal lens, and each first feed antenna is connected and fixed to a support column inside the metal lens through a support frame;

[0023] Among them, the metal lens 1 is composed of multiple metal plates, which are connected together by support columns 4. The spacing between the metal plates is equal and less than half the wavelength of the highest operating frequency. Each layer of metal plates is parallel to each other. The parallel metal plates form an air-filled parallel plate waveguide. After the electromagnetic wave of the first feed antenna 2 is transmitted to the metal lens 1, it propagates along the air gap between the metal plates. The transmission mode is the main mode of the parallel plate waveguide. By changing the angle between the metal plate and the first feed antenna 2, the outgoing phase of the incident electromagnetic wave after passing through the metal lens 1 is adjusted. When the phase error is minimized, high-gain radiation is achieved.

[0024] Furthermore, a plurality of first feed antennas 2 surround the outer periphery below the metal lens 1 in a circle, and the plurality of first feed antennas 2 are arranged at equal intervals to achieve 360° scanning of the first beam 6 in a circle.

[0025] Furthermore, the upper part of the metal plate in the metal lens 1 is removed to achieve miniaturization, and the amount of the removed metal plate is one third to one half of the entire metal plate.

[0026] like Figure 3 As shown, a plurality of second feed antennas 5 are arranged above the metal lens 1, and the plurality of second feed antennas 5 are connected and fixed to the support column 4 inside the metal lens 1 through the support frame 3. The plurality of second feed antennas 5 surround the outer periphery above the metal lens 1, and the plurality of second feed antennas 5 are arranged at equal intervals to achieve 360° scanning of the second beam 7 in one circle, which can be combined with the first beam 6 and the second beam 7 to achieve 360° horizontal plane scanning in two directions.

[0027] Furthermore, there is a corresponding second feed antenna 5 above each first feed antenna 2 , and the first feed antenna 2 and the second feed antenna 5 are symmetrical in an up-down manner.

[0028] like Figure 4 and Figure 5As shown, the antenna at the feed position is polarized in the y-direction. After being transmitted to the metal lens 1, it propagates along the air gap between the metal plates, changing the electromagnetic wave's propagation path. The parallel metal plates in the lens structure form an air-filled parallel plate waveguide. When electromagnetic waves polarized in the y-direction propagate through the lens, they follow the main mode of the parallel plate waveguide, with the same phase velocity as in air. To ensure the transmission of the main mode, the spacing between the metal plates should be less than half the wavelength of the highest operating frequency. Therefore, once the lens radius and the distance between the feed and the lens are determined, the exit phase of the incident electromagnetic wave after passing through the lens can be adjusted by changing the angle between the lens's metal plates and the x-axis. When the phase error is minimized, high-gain radiation can be achieved.

[0029] The specific derivation process is as follows:

[0030] From the cosine theorem we know that l1 2 + (F + R) 2 -2×(F+R)×l1=R 2 , get l1=(F+R)×cosθ-(((F+R)×cosθ) 2 -F×(F+2R) 0.5 , l2=2×R×sin(π-α-β)=2×R×(sinβ×cosα+ sinα×cosβ);

[0031] From the geometric relationship, we can get: cosβ= l1×sinθ / R, sinβ=(1-cos 2 β) 0.5 , l2=2×R×((1-cos 2 β) 0.5 ×cosα+ sinα×l1×sinθ / R)=2×R×((1-(l1×sinθ / R) 2 ) 0.5 ×cosα+ sinα×l1×sinθ / R), l3=F+2×R- l2×cosα- l1×cosθ.

[0032] The final path sum is l = l1 + l2 + l3.

[0033] After derivation, it is concluded that the light path changes with the incident angle θ. When the path difference of all effective incident angles is minimized, the maximum gain is achieved. There is a special angle that minimizes the phase error and achieves high-gain radiation. Figure 6 As shown in the figure, the simulated electric field distribution of the metal lens 1 is displayed. It can be seen that the electromagnetic wave radiated by the feed source can realize a good plane wave after passing through the lens. However, due to the inclination of the metal plate of the lens, only a small amount of energy is transmitted in area 1. In practical applications, this area can be removed to achieve miniaturization.

[0034] The foregoing description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Rather, the present invention is capable of various other combinations, modifications, and improvements, and is capable of modifications within the scope of the concepts described herein, through the above teachings, or through techniques or knowledge in the relevant fields. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be within the scope of the appended claims.

Claims

1. A full metal spherical lens antenna, characterized by: It comprises a metal lens (1) with a spherical structure, a plurality of first feed antennas (2) are arranged below the metal lens (1), and each first feed antenna (2) is connected and fixed to a support column (4) inside the metal lens (1) via a support frame (3); The metal lens (1) is composed of a plurality of metal plates, which are connected together by support columns (4). The spacing between the metal plates is equal and less than half the wavelength of the highest operating frequency. Each layer of metal plates is parallel to each other. The parallel metal plates form an air-filled parallel plate waveguide. After the electromagnetic wave of the first feed antenna (2) is transmitted to the metal lens (1), it propagates along the air gap between the metal plates. The transmission mode is the main mode of the parallel plate waveguide. By changing the angle between the metal plate and the first feed antenna (2), the output phase of the incident electromagnetic wave after passing through the metal lens (1) is adjusted. When the phase error is minimized, high-gain radiation is achieved. A plurality of first feed antennas (2) surround the outer periphery below the metal lens (1), and the plurality of first feed antennas (2) are arranged at equal intervals to achieve 360° scanning of the first beam (6) in one circle.

2. The all-metal spherical lens antenna according to claim 1, characterized in that: The upper portion of the metal plate in the metal lens (1) is removed to achieve miniaturization, and the amount of the removed metal plate is one third to one half of the entire metal plate.

3. The all-metal spherical lens antenna according to claim 1, characterized in that: A plurality of second feed antennas (5) are arranged above the metal lens (1). The plurality of second feed antennas (5) are connected and fixed to the support column (4) inside the metal lens (1) through the support frame (3). The plurality of second feed antennas (5) surround the outer periphery above the metal lens (1) in a circle, and the plurality of second feed antennas (5) are arranged at equal intervals, so as to achieve 360° scanning of the second beam (7) in a circle.

4. The all-metal spherical lens antenna according to claim 3, characterized in that: There is a corresponding second feed antenna (5) above each first feed antenna (2), and the first feed antenna (2) and the second feed antenna (5) are in a vertically symmetrical relationship.

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