All-metal spherical lens antenna

Abstract

The invention relates to an all-metal spherical lens antenna which comprises a metal lens of a spherical structure, a plurality of first feed source antennas are arranged below the metal lens, and each first feed source antenna is fixedly connected with a supporting column in the metal lens through a supporting frame; the metal lens is composed of a plurality of metal plates, the distances between the metal plates are equal and smaller than the half-wavelength of the highest working frequency, all the metal plates are parallel to one another, the parallel metal plates form an air-filled parallel slab waveguide, and after electromagnetic waves of the first feed source antenna are transmitted to the metal lens, the electromagnetic waves are transmitted to the metal lens. The incident electromagnetic waves propagate along the air gap between the metal plates, the emergent phase of the incident electromagnetic waves after passing through the metal lens is adjusted by changing the angle between the metal plates and the first feed source antenna, and when the phase error is minimum, high-gain radiation is achieved. The spherical metal lens structure is realized by using the combination of the metal flat plates, and the minimum phase error is realized by changing the inclination angles of the metal flat plates, so that the high-gain radiation wave beam is realized.

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

[0003] In traditional antenna technology, Luneburg lenses, dielectric spherical lens antennas, phased array antenna systems, reflective array antennas, and transmission array antennas have all played an important role, but there are also some shortcomings in practical applications, which are mainly due to the limitations of material properties, manufacturing processes, and electromagnetic theory and physical principles. Luneburg lenses need to have a continuously gradient refractive index from the center to the surface. This continuous refractive index distribution is difficult to achieve accurately in the actual manufacturing process. It is usually necessary to layer the lens, and each layer uses a different dielectric constant material to achieve a gradient approximation, which increases the complexity and cost of manufacturing. In addition, in order to obtain high gain and good focusing performance, the size of the Luneburg lens is usually large. This may not be practical in space-constrained or weight-sensitive applications. Specific dielectric materials are required to achieve a gradient refractive index. These materials may have problems such as high dielectric loss, poor temperature stability, or insufficient mechanical strength, which affects the performance and reliability of the lens. These shortcomings are mainly due to the difficulty of refractive index requirements and engineering implementation, as well as the limitations of material properties. Because the refractive index of the dielectric spherical lens antenna is constant, it is impossible to achieve consistent phase compensation for electromagnetic waves of different frequencies, resulting in a narrow working bandwidth. The constant refractive index makes it impossible for the lens to achieve perfect wavefront matching, and the focusing effect is not as good as that of a lens with a gradient refractive index, which affects the gain and directivity. In addition, the dielectric constant of the dielectric material and the air is quite different, which will cause reflection at the interface, reduce the transmission efficiency of the lens, and the loss of the dielectric material will also cause energy loss. These shortcomings are mainly due to the limitation of the single refractive index and optical principles, as well as the influence of material properties. Phased array antennas require precise control of the amplitude and phase of a large number of array elements, involving complex electronic control and signal processing devices, which increases the complexity and cost of the system. Active phased arrays need to provide independent amplification and phase control devices for each array element, which has a large overall power consumption and is not conducive to energy saving. When working in broadband, the frequency response of the array element and the phase shifter may be inconsistent, affecting the accuracy of beamforming, and array effects such as grating lobes and increased side lobes may occur, affecting the performance of the antenna. These shortcomings are mainly due to the complex control system caused by the need for flexible beam control, the technical challenges of maintaining consistency in the performance of electronic devices within a wide frequency band, 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 beyond this frequency range, resulting in a narrow bandwidth. The beam scanning of traditional reflection array antennas requires adjustment of the unit phase, and the electronic control is complex and the scanning angle is 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. The complex phase control system required to achieve wide-angle and fast beam scanning increases the technical difficulty, as well as impedance matching problems caused by design complexity.

[0004] In summary, traditional antenna technologies have their own limitations in achieving broadband and multi-beam characteristics. Currently, there is no all-metal spherical multi-beam lens that can achieve 360° beam coverage. These shortcomings are mainly due to material properties, manufacturing process limitations, and limitations of electromagnetic theory and physical principles. 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 deficiencies of the prior art.

[0006] The object of the present invention is achieved by the following technical solutions: a full metal spherical lens antenna, which includes a metal lens with a spherical structure, 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; The metal lens comprises a plurality of metal plates, which are connected together by supporting 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, and the parallel metal plates form an air-filled parallel flat 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, and the transmission mode is the main mode of the parallel flat waveguide. By changing the angle between the metal plate and the first feed antenna, the outgoing phase of the incident electromagnetic wave after passing through the metal lens is adjusted, and when the phase error is minimized, high-gain radiation is achieved.

[0007] A plurality of first feed antennas surround the outer periphery below the metal lens in a circle, and the plurality of first feed antennas are arranged at equal intervals to achieve a 360° scan of the first beam in a circle.

[0008] 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.

[0009] 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 a circle.

[0010] There is a corresponding second feed antenna above each first feed antenna, and the first feed antenna and the second feed antenna are symmetrical in an up-and-down manner.

[0011] 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, achieves minimum 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 achieves 360° beam coverage by adding multiple feed sources; adopts an all-metal structure, avoids the use of dielectric materials, avoids dielectric loss, and improves the radiation efficiency of the antenna; adopts the main mode TEM mode of parallel flat plates, which theoretically has no cut-off frequency, and can work as long as the spacing between the metal plates is less than half the wavelength of the highest operating frequency, so theoretically the lens can meet ultra-wideband applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a side view structural schematic diagram of the present invention; Figure 3 It is a schematic diagram of the dual-feed dual-beam of the present invention; Figure 4 Schematic diagram of electromagnetic wave incident on the upper half plane of the metal lens; Figure 5 Schematic diagram of electromagnetic wave incident on the lower half plane of the metal lens; Figure 6 Schematic diagram of the simulated electromagnetic distribution 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

[0013] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme 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 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 application claimed for protection, 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 belong to the scope of protection of the present application. The present invention is further described below in conjunction with the drawings.

[0014] The present invention specifically relates to a full-metal spherical lens antenna, which focuses and controls the incident electromagnetic waves by designing the tilt angle of the flat plate relative to the feed source, thereby 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 to form multiple radiation beams to achieve 360-degree all-round coverage.

[0015] like Figure 1 and Figure 2 As shown, it specifically includes a metal lens of 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; Among them, the metal lens 1 includes 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.

[0016] 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 a 360° scan of a circle of the first beam 6 .

[0017] 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.

[0018] 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 a 360° scan of a circle of the second beam 7, which can be combined with the first beam 6 and the second beam 7 to achieve a 360° horizontal plane scan in two directions.

[0019] 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 in a vertically symmetrical relationship.

[0020] 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 will propagate along the air gap between the metal plates, changing the electromagnetic wave transmission path. The parallel metal plates in the lens structure form an air-filled parallel plate waveguide. When the electromagnetic wave polarized in the y direction is transmitted in the lens, the mode is the main mode of the parallel plate waveguide, and the phase velocity is the same as that in the air. In order 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, when the radius of the lens and the distance between the feed source and the lens are determined, the angle between the lens metal plate and the x-axis can be changed to adjust the output phase of the incident electromagnetic wave after passing through the lens. When the phase error is minimized, high gain radiation can be achieved.

[0021] The specific derivation process is as follows: 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); 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.

[0022] The final path sum is l= l1+ l2+ l3.

[0023] 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 the smallest, the maximum gain is achieved. There is a special angle that minimizes the phase error and achieves high-gain radiation. Figure 6 As shown, 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, but 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.

[0024] The above is only 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 regarded as excluding other embodiments, but can be used for various other combinations, modifications and improvements, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A full metal spherical lens antenna, characterized in that: 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) comprises a plurality of metal plates, which are connected together via 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, and 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, and 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, and when the phase error is minimized, high-gain radiation is achieved.

2. The all-metal spherical lens antenna according to claim 1, characterized in that: 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 a first beam (6) in a circle.

3. The all-metal spherical lens antenna according to claim 2, characterized in that: 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.

4. The all-metal spherical lens antenna according to claim 2, 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 a support column (4) inside the metal lens (1) via a support frame (3); the plurality of second feed antennas (5) surround the metal lens (1) in a circle, and the plurality of second feed antennas (5) are arranged at equal intervals to achieve 360° scanning of a circle of the second beam (7).

5. The all-metal spherical lens antenna according to claim 4, 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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