A waveguide slot antenna fed by a luneberg lens

Abstract

Provided is a waveguide slot antenna array fed by a Luneberg lens, comprising an open waveguide, a parallel flat waveguide, a cylindrical Luneberg lens and a waveguide slot antenna array; the parallel flat waveguide is composed of an upper metal flat plate and a lower metal flat plate which are spaced apart and parallel; the end of the parallel flat waveguide is in conductive connection with the feed port surface of the waveguide slot antenna array; the opening of the parallel flat waveguide is connected with the radiation port surface of the open waveguide; the cylindrical Luneberg lens is arranged between the upper metal flat plate and the lower metal flat plate; the cylindrical Luneberg lens feeds the waveguide slot antenna array, and the waveguide slot antenna array is arranged on the upper end surface of the upper metal flat plate; and the radiation port surface of the open waveguide is arranged on the surface of the cylindrical Luneberg lens. The structure is simple and easy to process, the feed structure has a wideband characteristic, is suitable for waveguide slot antenna arrays of various frequency bands, has a compact structure, a low overall profile, realizes high gain, and has the characteristics of low loss, high power and stable performance.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology that utilizes lens refraction, and specifically relates to a waveguide slot antenna array fed by a Luneburg lens. Background Technology

[0002] Ku-band high-gain antennas are most widely used in satellite communication systems. This band is also commonly used in satellite internet applications in maritime and oil platform sectors, where high gain is required. On mobile platforms such as vehicles and ships, high gain with a low profile, structural stability, and high power handling are also necessary. To comprehensively achieve these characteristics, the commonly used approach is to employ waveguide slot antenna arrays, thus meeting the requirements of low profile, high gain, low loss, high power capacity, and stable performance.

[0003] However, to fully meet the high-gain requirements, waveguide slot antenna arrays often have a large number of elements, resulting in increasingly complex feeding networks and increased design and fabrication difficulties. In the design process, in addition to considering the bandwidth of the waveguide slot antenna elements, the bandwidth of the feeding network must also be taken into account. Therefore, designing a broadband feed structure for waveguide slot antenna arrays and achieving a simple and lightweight feed structure is of great significance. The following improved technical solution is proposed. Summary of the Invention

[0004] The technical problem solved by this invention is to provide a waveguide slot antenna array fed by a Luneburg lens, which solves the technical problem of how to simplify the design of the waveguide slot antenna array and meets the requirements of low profile, high gain, low loss, high power and stable performance of the antenna.

[0005] The technical solution adopted in this invention is as follows: a waveguide slot antenna array fed by a Luneburg lens, comprising an open waveguide, a parallel planar waveguide, a cylindrical Luneburg lens, and a waveguide slot antenna array; the parallel planar waveguide is composed of an upper metal plate and a lower metal plate that are spaced apart and parallel to each other; the end of the parallel planar waveguide is conductively connected to the feed port of the waveguide slot antenna array; the opening of the parallel planar waveguide is connected to the radiation port of the open waveguide; the cylindrical Luneburg lens is disposed between the upper and lower metal plates; the cylindrical Luneburg lens feeds the waveguide slot antenna array, and the waveguide slot antenna array is placed on the upper end face of the upper metal plate; the radiation port of the open waveguide is placed on the surface of the cylindrical Luneburg lens.

[0006] In the above technical solution, as a further improvement of the present invention: the open waveguide is fed by a wave-to-wave conversion structure.

[0007] As a further improvement of the present invention, the parallel planar waveguide end conduction connection portion is provided with an electromagnetic wave transition structure.

[0008] In the above technical solution, preferably, the electromagnetic wave transition structure is a metal inclined structure at the connection between the end of the parallel planar waveguide and the feed port of the waveguide slot antenna array.

[0009] In the above technical solution, as a further improvement of the present invention: the cylindrical Luneburg lens has an axisymmetric structure and has axisymmetric upper and lower cylindrical surfaces. A plurality of small cylindrical units are arranged vertically between the upper and lower cylindrical surfaces. The cylindrical surfaces are in close contact with the two metal surfaces of the parallel planar waveguide. The small cylindrical units all have the same height, and the height is equal to the distance between the upper and lower cylindrical surfaces. The small cylindrical units have different radii, and the radii gradually decrease from the center of the cylindrical Luneburg lens to the outer periphery.

[0010] As a further improvement of the present invention, the cylindrical Luneburg lens is processed by 3D printing technology, and the material used for 3D printing is PLA with a relative permittivity of 3 to 3.5.

[0011] In the above technical solution, preferably: the waveguide slot antenna array is composed of N identical waveguide slot antenna arrays, where N≥2; a preset distance is left between adjacent waveguide slot antennas and grooves are engraved; each waveguide slot antenna has M slots engraved on it, where M≥1; the M slots are distributed in a crisscross manner on the left and right sides of the central axis of the waveguide slot antenna.

[0012] In the above technical solution, the preferred configuration is N=7, and the 7 identical waveguide slot antennas are arranged linearly.

[0013] In the above technical solution, the preferred configuration is M=9, and the nine slots are arranged at equal intervals along the length direction of the waveguide slot antenna, and the slots are parallel to the central axis of the waveguide slot antenna.

[0014] Advantages of this invention compared to existing technologies:

[0015] 1. The antenna of this invention has a simple overall structure, is easy to process, and has high gain characteristics; the feeding structure has broadband characteristics and is suitable for waveguide slot antenna arrays of various frequency bands. In addition, the antenna structure is compact and has a low overall profile, achieving high gain while also having the characteristics of low loss, high power and stable performance.

[0016] 2. This invention employs a wave-to-wave conversion structure for power supply, enabling the conversion of electromagnetic wave modes between coaxial lines and rectangular waveguides. The wave-to-wave conversion structure facilitates the connection of open waveguides with different types of subsequent equipment or transmission lines, making system integration easier. It also offers flexibility and designability, improves environmental adaptability, and ensures long-term stable performance.

[0017] 3. The electromagnetic wave transition structure of this invention can reduce electromagnetic wave reflection and improve transmission efficiency; optimize antenna performance and stabilize the operating frequency band; and enhance system reliability and stability.

[0018] 4. The cylindrical Luneburg lens of this invention achieves precise gradient of dielectric constant, has good phase modulation performance, and modulates spherical waves into plane waves; the 3D printing process used simplifies design and manufacturing, facilitates integration with parallel planar waveguides, and the regularity of the arrangement of small cylindrical units is conducive to manufacturing and quality control; it has stable wideband performance and reduces frequency dispersion effects; it has high structural stability and strong environmental adaptability.

[0019] 5. The cylindrical Luneburg lens 3D printed by this invention can be precisely molded, optimizes electromagnetic performance, facilitates gradient dielectric constant distribution, and enables integrated manufacturing of complex structures; PLA material with a dielectric constant of 3-3.5 has low loss and wide bandwidth characteristics, is lightweight, has excellent environmental resistance, and significantly reduces costs; 3D printing enables precise control of micro-sizes, meeting the stringent requirements of Luneburg lenses for layer thickness and refractive index distribution, requires no support structure, allows for efficient production, rapid iteration, and customized design; meets the potential expansion needs of multi-scenario applications; breaks through traditional technical bottlenecks, and conforms to the trend of green manufacturing.

[0020] 6. The preferred 3D printing material of this invention is PLA, which is biodegradable, environmentally friendly and safe, has excellent printing performance, low shrinkage rate, high printing quality, meets good mechanical properties and usage requirements, and is low in cost and highly efficient.

[0021] 7. The waveguide slot antenna array of this invention significantly improves the overall performance of the antenna through multi-dimensional optimization, including array size, spacing control, and slot distribution, achieving high gain and strong directivity to meet the needs of long-distance communication; the groove design reduces mutual coupling between slots; the modular design facilitates maintenance and mass production, and it can be integrated with Luneburg lenses, providing strong compatibility. Attached Figure Description

[0022] Figure 1 This is a structural diagram of the present invention;

[0023] Figure 2 This is a structural diagram of the cylindrical Luneburg lens of the present invention;

[0024] Figure 3 The waveguide slot antenna array S fed by the Luneburg lens of this invention 11 picture;

[0025] Figure 4 This is the E-plane gain pattern at 14.6 GHz according to the present invention;

[0026] Figure 5 This is the H-plane gain pattern at 14.6 GHz according to the present invention;

[0027] Figure 6 This is the E-plane gain pattern at 14.9 GHz according to the present invention;

[0028] Figure 7 This is the H-plane gain pattern at 14.9 GHz according to the present invention;

[0029] Figure 8 This is the E-plane gain pattern at 15.2 GHz according to the present invention;

[0030] Figure 9 This is the H-plane gain pattern at 15.2 GHz according to the present invention;

[0031] In the figure: 1-Open waveguide, 2-Parallel planar waveguide, 201-Upper metal plate, 202-Lower metal plate, 3-Cylindrical Luneburg lens, 4-Waveguide slot antenna array, 401-Waveguide slot antenna, 5-Wave co-conversion structure, 6-Electromagnetic wave transition structure, 7-Small cylindrical unit, 8-Cylindrical surface, 9-Groove, 4011-Slot. Detailed Implementation

[0032] The following will refer to the appendices in the embodiments of the present invention. Figure 1-9 The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] (like Figure 1 (As shown) A waveguide slot antenna array fed by a Luneburg lens includes an open waveguide 1, a parallel planar waveguide 2, a cylindrical Luneburg lens 3, and a waveguide slot antenna array 4. The parallel planar waveguide 2 is composed of an upper metal plate 201 and a lower metal plate 202 that are spaced apart and parallel to each other. The end of the parallel planar waveguide 2 is conductively connected to the feed port of the waveguide slot antenna array 4. The opening of the parallel planar waveguide 2 is connected to the radiation port of the open waveguide 1. The cylindrical Luneburg lens 3 is disposed between the upper metal plate 201 and the lower metal plate 202. The cylindrical Luneburg lens 3 feeds the waveguide slot antenna array 4, and the waveguide slot antenna array 4 is placed on the upper end face of the upper metal plate 201. The radiation port of the open waveguide 1 is placed on the surface of the cylindrical Luneburg lens 3.

[0034] It should be noted that the antenna of this invention has a simple overall structure, is easy to process, and has high gain characteristics; the feeding structure has broadband characteristics and is suitable for waveguide slot antenna arrays of various frequency bands. In addition, the antenna structure is compact and has a low overall profile, achieving high gain while also having the characteristics of low loss, high power, and stable performance.

[0035] In terms of overall structural simplicity, ease of fabrication, and high gain characteristics, the components of this invention are simple, clear, and independent, and the processing technology for each component is relatively mature. The cylindrical Luneburg lens has a unique refractive index distribution, enabling it to focus incident electromagnetic waves. When electromagnetic waves radiated from the open waveguide enter the Luneburg lens, the lens gradually converges the beam, concentrating more energy in a specific direction. This focusing effect is similar to the focusing of light by a convex lens in optics, converting the spherical waves radiated from the feed source into plane waves, thereby feeding the waveguide slot antenna array. The waveguide slot antenna array consists of multiple slot elements, which, under the excitation of plane waves, can form a cooperative radiation effect. By rationally designing the size, spacing, and arrangement of the slot elements, the radiation pattern of the antenna array can be controlled, achieving higher gain in the main lobe direction.

[0036] In terms of wideband feeding structures suitable for waveguide slot antenna arrays across various frequency bands: Parallel planar waveguides are a wideband transmission structure with relatively stable transmission characteristics within a certain frequency range. Compared to traditional rectangular or circular waveguides, parallel planar waveguides have a lower cutoff frequency and can transmit over a wider frequency range. This allows them to provide stable feeding for waveguide slot antenna arrays in different frequency bands, meeting the needs of multi-band communication and radar systems. Cylindrical Luneburg lenses have a certain adaptability to electromagnetic waves of different frequencies. Luneburg lenses can maintain good plane wave modulation performance over a wide frequency band. Therefore, this feeding structure can adapt to waveguide slot antenna arrays in different frequency bands, achieving wideband feeding.

[0037] In terms of compact antenna structure and low overall profile: this antenna organically integrates open waveguides, parallel planar waveguides, cylindrical Luneburg lenses, and waveguide slot antenna arrays, with a compact layout of each component and a small footprint. The waveguide slot antenna array is placed on the upper surface of the upper metal plate, and the overall thickness of the antenna mainly depends on the spacing of the parallel planar waveguides and the height of the cylindrical Luneburg lenses. By rationally designing these parameters, a low profile antenna design can be achieved.

[0038] Regarding low-loss characteristics: the metal walls of the parallel planar waveguide have good conductivity, effectively reducing ohmic loss during electromagnetic wave transmission. Simultaneously, the simple structure of the parallel planar waveguide, without complex internal structures, reduces scattering loss caused by structural inhomogeneities. Therefore, electromagnetic waves experience less energy loss during transmission within the parallel planar waveguide, ensuring more energy reaches the waveguide slot antenna array. In particular, when the cylindrical Luneburg lens is made of low-loss PLA dielectric material, it exhibits low dielectric and magnetic losses in the microwave band, reducing absorption losses of electromagnetic waves within the lens. Therefore, the Luneburg lens focuses electromagnetic waves without introducing excessive energy loss, ensuring high-efficiency radiation of the antenna system.

[0039] Regarding high-power characteristics: the metal components of open waveguides, parallel planar waveguides, and waveguide slot antenna arrays possess excellent thermal conductivity and mechanical strength, enabling them to withstand high power inputs. Under high-temperature or high-power operating conditions, the metal components can dissipate the generated heat promptly, preventing damage due to overheating. Simultaneously, the mechanical strength of the metal materials ensures that the antenna will not deform or be damaged under external forces, guaranteeing the stable operation of the antenna system. The low-loss dielectric material used in the cylindrical Luneburg lens not only has low loss but also good power stability. Under the influence of high-power electromagnetic waves, the dielectric material will not experience breakdown or performance degradation, ensuring the focusing performance and feed stability of the Luneburg lens. Therefore, this antenna system can withstand high power inputs and is suitable for high-power communication and radar systems.

[0040] Regarding performance stability: All components of this antenna exhibit good adaptability to environmental factors (such as temperature, humidity, and vibration). Metal components maintain stable mechanical and electrical properties under varying temperature conditions, without significant deformation or resistance changes due to temperature variations. The low-loss dielectric material also possesses good temperature and chemical stability, enabling long-term stable operation under harsh environmental conditions. Due to its simple structure, high component manufacturing precision, strong power handling capability, and good environmental adaptability, this antenna system boasts high long-term operational reliability. In practical applications, it can operate stably for extended periods, reducing the frequency of maintenance and replacement, and lowering operating costs.

[0041] In the above embodiments, as a further improvement of the present invention, the open waveguide 1 is fed by a wave-to-wave conversion structure 5 as a feed source.

[0042] It should be noted that the present invention uses a wave-to-wave conversion structure for power supply to achieve the conversion of electromagnetic wave modes between coaxial lines and rectangular waveguides. The wave-to-wave conversion structure facilitates the connection of open waveguides with different types of subsequent equipment or transmission lines, making system integration easier, and providing a certain degree of flexibility and designability. It can also improve environmental adaptability and ensure long-term stable performance.

[0043] In terms of achieving electromagnetic wave mode conversion between coaxial lines and rectangular waveguides, transmission loss is reduced by utilizing the mode matching principle. Specifically, regarding the mode matching principle: coaxial lines transmit TEM modes (transverse electromagnetic wave modes), whose electric and magnetic fields are perpendicular to the propagation direction; while rectangular waveguides typically transmit TE modes (transverse electromagnetic wave modes) or TM modes (transverse magnetic wave modes), such as the common TE... 10 Mode conversion structures, through specific designs such as gradient structures and matching networks, enable the TEM mode in a coaxial line to gradually transition to the TE or TM mode in a rectangular waveguide, achieving efficient conversion between electromagnetic wave modes of two different transmission lines.

[0044] In particular, the wave-to-coaxial converter (WTC) facilitates connections between open waveguides and various types of subsequent equipment or transmission lines, thus simplifying system integration. In practical applications, antenna systems often need to connect to various types of equipment (such as transmitters, receivers, power amplifiers, etc.) and transmission lines (such as coaxial cables and optical fibers). The WTC has a standardized interface design, allowing for easy connection to coaxial lines, while its output can be well matched with open waveguides (a type of rectangular waveguide). This compatibility allows the antenna system to be easily integrated into various complex communication or radar systems without requiring complex adaptations to different equipment. For example, in a large satellite communication system, the antenna needs to connect to the transmitter and receiver at the ground station, as well as to coaxial cables and waveguide transmission lines of different frequency bands. Using a WTC simplifies the connection process and improves system integration efficiency. Because the WTC facilitates connections between different transmission lines and equipment, it simplifies the overall antenna system layout. When designing the system, there is no need to consider complex connection methods and spatial layouts; simply installing the WTC in a suitable location ensures smooth signal transmission. This not only saves system space but also reduces the complexity and cost of system design. For example, in aircraft communication systems, where space is very limited, using a wave-to-wave conversion structure can make the antenna system layout more compact and improve space utilization.

[0045] In terms of improving environmental adaptability and long-term performance stability: Wavelength conversion structures typically employ a sealed design, effectively preventing the influence of external environments (such as dust, moisture, and corrosive gases) on the internal structure. Simultaneously, material selection also considers environmental adaptability, employing corrosion-resistant and high-temperature-resistant materials to ensure long-term stable operation under harsh environmental conditions. For example, in marine environments, antenna systems need to withstand seawater corrosion and high humidity; using a wavelength conversion structure with good environmental adaptability ensures long-term reliable operation of the antenna system in marine environments. Due to the simple structure, high reliability, and design considerations for long-term use, the performance of the wavelength conversion structure remains stable during long-term use. Compared to some complex connection methods, wavelength conversion structures are less prone to aging and loosening, ensuring that the antenna system maintains good signal transmission performance throughout long-term operation. For example, in communication base stations requiring continuous long-term operation, using a stable wavelength conversion structure can reduce the frequency of maintenance and replacement, lowering operating costs.

[0046] In the above embodiments, as a further improvement of the present invention, an electromagnetic wave transition structure 6 is provided at the end of the parallel planar waveguide 2 for conducting connection.

[0047] It should be noted that the electromagnetic wave transition structure 6 of this invention can reduce electromagnetic wave reflection, improve transmission efficiency, optimize antenna performance, stabilize the operating frequency band, and enhance system reliability and stability.

[0048] In terms of enhancing system reliability and stability: Reflected waves propagating back and forth within the waveguide may cause electromagnetic interference with other electronic devices or signals. This interference can affect the normal operation of the system, leading to signal distortion, increased bit error rate, and other problems. Electromagnetic wave transition structures reduce reflection, lowering the level of electromagnetic interference within the waveguide and improving the system's anti-interference capability. For example, in a complex communication base station system, multiple antennas and electronic devices operate simultaneously in a complex electromagnetic environment. By setting up an electromagnetic wave transition structure, reflected waves within the antenna waveguide can be reduced, minimizing interference with other devices and improving the overall system reliability and stability. The repeated oscillation of reflected waves within the waveguide generates additional energy loss, which is released as heat, causing the waveguide and related components to heat up. Prolonged high-temperature operation accelerates component aging and damage, reducing component lifespan. Electromagnetic wave transition structures reduce reflection, lowering energy loss and component heat generation, thereby extending component lifespan. In practical applications, antenna systems may face various complex environmental conditions, such as temperature changes, vibration, and shock. These environmental factors may affect the performance of the waveguide and connecting components, leading to impedance changes and increased reflection. Electromagnetic wave transition structures possess a certain degree of adaptability and robustness, enabling them to resist the effects of environmental factors to a certain extent, maintaining their function of reducing reflections and optimizing performance, thereby enhancing the reliability and stability of the entire antenna system in complex environments. For example, in the aerospace field, antenna systems need to withstand extreme temperature changes and strong vibrations and shocks; employing electromagnetic wave transition structures with good environmental adaptability can ensure that the antenna system operates normally in these harsh environments.

[0049] In the above embodiments, preferably, the electromagnetic wave transition structure 6 is a metal inclined structure at the point where the end of the parallel planar waveguide 2 is connected to the feed port surface of the waveguide slot antenna array 4.

[0050] It should be noted that the above-mentioned electromagnetic wave transition structure can effectively reduce electromagnetic wave reflection, achieve impedance gradient, and optimize electromagnetic field distribution; improve transmission efficiency, reduce energy loss, increase power capacity, and improve transmission efficiency; stabilize the operating frequency band and optimize antenna performance by improving the radiation pattern; reduce electromagnetic interference, adapt to complex environments, and enhance system reliability and stability; in addition, the process is relatively simple, easy to install and debug, and conducive to large-scale production.

[0051] In the above embodiments, as a further improvement of the present invention: the cylindrical Luneburg lens 3 has an axisymmetric structure and has axisymmetric upper and lower cylindrical surfaces 8. A plurality of small cylindrical units 7 are vertically arranged between the upper and lower cylindrical surfaces 8. The cylindrical surfaces 8 are in close contact with the two metal surfaces of the parallel planar waveguide 2. The small cylindrical units 7 all have the same height, and the height is equal to the distance between the upper and lower cylindrical surfaces 8. The small cylindrical units 7 have different radii, and the radii gradually decrease from the center of the cylindrical Luneburg lens 3 to the outer periphery.

[0052] It should be noted that the cylindrical Luneburg lens of this invention achieves precise gradient of dielectric constant, has good phase modulation performance, and modulates spherical waves into plane waves; the 3D printing process used simplifies design and manufacturing, facilitates integration with parallel planar waveguides, and the regularity of the arrangement of small cylindrical units is conducive to manufacturing and quality control; it has stable wideband performance and reduces frequency dispersion effects; it has high structural stability and strong environmental adaptability.

[0053] In terms of achieving precise gradients in the dielectric constant, the underlying principle is based on the Luneburg lens's core principle of precisely controlling the propagation path of electromagnetic waves through a spatially gradual distribution of the dielectric constant. The cylindrical Luneburg lens of this invention employs an axisymmetric structure, with the radius of the small cylindrical units gradually decreasing from the center outwards. This design allows the small cylindrical units at different locations to have different dielectric constants. Since the dielectric constant is related to factors such as the unit's size and material, a precise gradient of the dielectric constant from the center to the periphery can be achieved by rationally designing the radius variation of the small cylindrical units. This precise gradient of the dielectric constant allows electromagnetic waves to be refracted and focused along a predetermined path when propagating inside the lens.

[0054] Among these applications, the Luneburg lens exhibits excellent control performance in converting spherical waves into plane waves. The phase control principle is as follows: When an electromagnetic wave is emitted from a point source, it forms a spherical wave, with different phases at different points on its wavefront. A cylindrical Luneburg lens, through its unique dielectric constant distribution, can produce different phase delays for electromagnetic waves at different locations. From the center to the periphery, as the dielectric constant changes, the propagation speed of the electromagnetic wave within the lens also changes, resulting in differences in phase delay. By rationally designing the gradual change in dielectric constant, the phases at different points on the wavefront of the spherical wave after passing through the lens can be made more consistent, thus achieving the conversion of the spherical wave into a plane wave. Converting spherical waves into plane waves has significant application value. In antenna systems, plane waves can improve the directivity and gain of the antenna, reduce sidelobe levels, and improve the antenna's radiation performance. For example, in satellite communication antennas, the cylindrical Luneburg lens of this invention can convert spherical waves emitted by the satellite into plane waves, enabling the antenna to receive and transmit signals more effectively and improve communication quality. Furthermore, plane waves also have significant advantages in target detection and imaging, improving system resolution and imaging quality.

[0055] Furthermore, the integration with the parallel planar waveguide, combined with the 3D printing process described later, simplifies design and manufacturing. Traditional lens manufacturing methods typically require complex mold making and processing, resulting in high costs and long lead times. In contrast, 3D printing can directly manufacture lenses from computer-designed 3D models by layer-by-layer material deposition, eliminating the need for molds and significantly simplifying the design and manufacturing process. For the cylindrical Luneburg lens of this invention, its axisymmetric structure and regularly arranged small cylindrical units are highly suitable for 3D printing, enabling the rapid and accurate manufacture of lenses that meet design requirements. 3D printing offers high design freedom, allowing for the precise manufacture of matching cylindrical Luneburg lenses based on the specific dimensions and structural requirements of the parallel planar waveguide. Simultaneously, 3D printing enables the integrated manufacturing of the lens and the parallel planar waveguide, reducing assembly steps and improving integration and reliability. For example, during manufacturing, the lens can be directly printed between the two metal layers of the parallel planar waveguide, ensuring a tight bond and reducing electromagnetic wave loss and reflection at the connection point, thus improving the overall system performance.

[0056] Regarding the advantages of the regular arrangement of small cylindrical units in manufacturing and quality control: the regularity of the arrangement of small cylindrical units, combined with the 3D printing process, makes the process more stable and controllable. During printing, the print head can print each small cylindrical unit sequentially according to a predetermined path and parameters, reducing errors and uncertainties in the printing process. Simultaneously, the regular arrangement of small cylindrical units facilitates the selection and optimization of printing materials, allowing for the selection of appropriate materials based on the performance requirements of different units, improving printing quality and efficiency. Because of the regularity of the arrangement of small cylindrical units, standardized testing methods and equipment can be used during quality inspection to accurately measure parameters such as the size, shape, and dielectric constant of each unit. By establishing quality control standards and testing procedures, defective products can be identified and eliminated promptly, ensuring the consistency of lens quality and performance. For example, optical measuring equipment can be used to quickly and accurately measure the radius of the small cylindrical units, ensuring they meet design requirements.

[0057] Regarding wideband performance stability and reduced frequency dispersion effects: The principle of wideband performance stability: Frequency dispersion effect refers to the variation of the dielectric constant and refractive index of a lens with frequency, resulting in different phase delays when electromagnetic waves of different frequencies propagate through the lens, thus affecting the lens's performance. The cylindrical Luneburg lens of this invention, through precise design of the size and arrangement of small cylindrical units, ensures that the dielectric constant of the lens remains relatively stable over a wide bandwidth. Within the wide bandwidth, electromagnetic waves of different frequencies propagate through the lens and achieve relatively consistent phase delays, thereby ensuring the lens's performance stability. This wideband performance stability makes the cylindrical Luneburg lens of this invention suitable for various communication and detection systems at different frequencies. In the field of wireless communication, with the development of communication technology, the demand for wideband communication is increasing. Using the lens of this invention can achieve stable signal transmission and reception over a wide bandwidth, improving the capacity and reliability of communication systems. In the field of radar detection, a lens with stable wideband performance can improve the radar's detection range and resolution, and reduce the impact of frequency interference on detection results.

[0058] Regarding high structural stability and strong environmental adaptability: The cylindrical Luneburg lens adopts an axisymmetric structure with closely spaced and regularly arranged small cylindrical units, resulting in high structural strength and stability. Under external forces, the lens can uniformly distribute stress, reducing damage caused by localized stress concentration. Furthermore, the lens material manufactured using 3D printing technology exhibits good uniformity and fewer internal defects, further enhancing the lens's structural stability. The cylindrical Luneburg lens of this invention demonstrates strong adaptability to environmental changes. In terms of temperature variations, the lens material exhibits excellent thermal stability and a well-matched coefficient of thermal expansion, maintaining dimensional and performance stability over a wide temperature range. The lens's structure and performance remain largely unchanged under the influence of environmental factors such as humidity, vibration, and impact. For example, in the aerospace field, antenna systems need to withstand extreme environmental conditions; the cylindrical Luneburg lens of this invention can meet the requirements for use in these harsh environments, ensuring the normal operation of the system.

[0059] In the above embodiments, as a further improvement of the present invention: the cylindrical Luneburg lens 3 is processed by 3D printing technology, and the material used for 3D printing is PLA with a relative permittivity of 3 to 3.5.

[0060] It should be noted that the cylindrical Luneburg lens 3D printed by this invention can be precisely molded, optimizes electromagnetic properties, facilitates the realization of gradient dielectric constant distribution, and enables integrated manufacturing of complex structures; PLA material with a dielectric constant of 3 to 3.5 has low loss and wide bandwidth characteristics, is lightweight, has excellent environmental resistance, and significantly reduces costs; 3D printing enables precise control of minute dimensions, meeting the stringent requirements of Luneburg lenses for layer thickness and refractive index distribution, requires no support structure, allows for efficient production, rapid iteration, and customized design; meets the potential expansion needs of multi-scenario applications; breaks through traditional technical bottlenecks, and conforms to the trend of green manufacturing.

[0061] Furthermore, it should be noted that the preferred 3D printing material of this invention is PLA, which is biodegradable, environmentally friendly and safe, has excellent printing performance, low shrinkage rate, high printing quality, meets good mechanical properties and usage requirements, and is low in cost and highly efficient.

[0062] As can be seen, the waveguide slot antenna array of this invention significantly improves the overall performance of the antenna through multi-dimensional optimization, including array size, spacing control, and slot distribution, achieving high gain and strong directivity to meet the needs of long-distance communication; the groove design reduces mutual coupling between slots; the modular design facilitates maintenance and mass production, and its integration with Luneburg lenses provides strong compatibility.

[0063] In the above embodiments, preferably: the waveguide slot antenna array 4 is composed of N identical waveguide slot antennas 401 arrays, where N≥2; a preset distance is left between adjacent waveguide slot antennas 401 and grooves 9 are engraved; each waveguide slot antenna 401 is engraved with M slots 4011, where M≥1; the M slots 4011 are distributed in a crisscross manner on the left and right sides of the central axis of the waveguide slot antenna 401.

[0064] In the above embodiments, preferably, N=7, and the 7 identical waveguide slot antennas 401 are arranged linearly.

[0065] It should be noted that, based on the area of ​​the lens and the parallel planar waveguide, to maximize aperture efficiency, a design with N=7 and 7 waveguide slot antennas 401 arranged linearly is preferred. This choice achieves the best balance between electromagnetic performance, engineering implementation, and cost-effectiveness, significantly improving main lobe gain and directivity, enhancing the array factor, optimizing the directivity coefficient, providing grating lobe suppression and bandwidth stability, improving bandwidth flatness, facilitating mechanical design, optimizing thermal management, modular design, enabling mass production, reducing unit cost, and facilitating efficient testing and maintenance; the balanced choice of 7-element scale achieves a balance between gain and sidelobes.

[0066] Among these, the linear array offers several advantages in electromagnetic performance optimization: significantly improved main lobe gain and directivity, and enhanced array factor. Linear arrangement narrows the beamwidth, significantly increasing energy concentration, reducing spatial interference, and optimizing the directivity coefficient. Precise control of the element spacing in the linear array improves bandwidth flatness, and the impedance matching and radiation modes of the linear array are more refined within the bandwidth.

[0067] In terms of engineering implementation, the design simplifies the structure, enhances reliability, and enables low-cost, large-scale production. The linear arrangement eliminates the need for complex support structures, allowing antenna positioning via a single-axis guide rail or fixed bracket, reducing assembly difficulty. The linear arrangement ensures uniform spacing between antenna elements, facilitating heat dissipation design. Seven identical elements can be mass-produced, reducing unit cost. The linear arrangement supports element-by-element testing and replacement, shortening troubleshooting time.

[0068] In the above embodiments, preferably, M=9, and the nine slots 4011 are arranged at equal intervals along the length direction of the waveguide slot antenna 401, and the slots 4011 are parallel to the central axis of the waveguide slot antenna 401.

[0069] It should be noted that the design with M=9 and nine slots evenly spaced along the length and parallel to the central axis allows for the one-time machining of the nine equally spaced parallel slots 4011, ensuring consistent performance during mass production. The parallel slot 4011 design facilitates integration with waveguide power dividers, phase shifters, and other modules. This design maximizes the use of waveguide wall material, reduces redundant structures, and maintains link stability during high-speed movement. The M=9 slot 4011 design, with its equally spaced parallel arrangement, achieves a perfect balance between high performance and engineering feasibility through multi-dimensional technological breakthroughs, including gain optimization, bandwidth expansion, improved polarization purity, and cost reduction. This design is not only suitable for traditional fields such as satellite communication and 5G base stations but can also be extended to emerging scenarios such as drones and autonomous driving, providing an efficient solution for high-frequency, high-capacity communication systems.

[0070] The working principle of this invention is as follows: Compared to existing high-gain waveguide slot antenna arrays, this invention does not use a power divider feed network for the waveguide slot antenna array 4. Instead, it employs plane wave feeding, combining a parallel planar waveguide 2 with a cylindrical Luneburg lens 3. The cylindrical Luneburg lens 3 is used to phase-modulate the electromagnetic waves radiated from the open waveguide 1. The parallel planar waveguide 2 feeds the waveguide slot antenna array 4 through an electromagnetic wave transition structure 6, reducing transmission loss. Regarding this feeding structure, the spacing of the parallel planar waveguide 2 can be flexibly adjusted, and the cylindrical Luneburg lens 3 has broadband characteristics. Therefore, in addition to the Ku-band slot antenna array in this invention, this feeding structure can also be applied to other frequency bands.

[0071] The present invention is as follows Figure 1The waveguide slot antenna array fed by the Luneburg lens shown is combined with Figure 3 S 11 Figure and Figures 4 to 9 As shown, the antenna S of the present invention 11 The gain is less than -15dB within the 14.5GHz - 15.2MHz frequency range, and the gain is 24.73dB, 24.85dB, and 24.33dB at 14.6GHz, 14.9GHz, and 15.2GHz, respectively, achieving high gain. This demonstrates that the Luneburg lens feeding structure of this invention achieves plane wave modulation of the spherical wave of the feed source, and can be used for feeding waveguide slot antenna array 4.

[0072] In summary, the antenna structure of this invention is simple, easy to manufacture, and has high gain characteristics; the feeding structure has broadband characteristics and is suitable for waveguide slot antenna arrays of various frequency bands. In addition, the antenna structure is compact and has a low overall profile, achieving high gain while also having the characteristics of low loss, high power, and stable performance.

[0073] The various embodiments in this specification are described in a related manner, and the same or similar parts between the various embodiments are explained.

[0074] The examples can be referred to interchangeably; each embodiment focuses on the differences from other embodiments.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications and equivalent substitutions made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A waveguide slot antenna array fed by a Luneburg lens, characterized in that: The system includes an open waveguide (1), a parallel planar waveguide (2), a cylindrical Luneburg lens (3), and a waveguide slot antenna array (4). The parallel planar waveguide (2) is composed of an upper metal plate (201) and a lower metal plate (202) that are spaced apart and parallel to each other. The end of the parallel planar waveguide (2) is connected to the feed port of the waveguide slot antenna array (4). The opening of the parallel planar waveguide (2) is connected to the radiation port of the open waveguide (1). The cylindrical Luneburg lens (3) is provided between the upper metal plate (201) and the lower metal plate (202). The cylindrical Luneburg lens (3) feeds the waveguide slot antenna array (4), and the waveguide slot antenna array (4) is placed on the upper end face of the upper metal plate (201). The radiation port of the open waveguide (1) is placed on the surface of the cylindrical Luneburg lens (3).

2. The waveguide slot antenna array fed by a Luneburg lens according to claim 1, characterized in that: The open waveguide (1) is fed by a wave-to-wave conversion structure (5).

3. The waveguide slot antenna array fed by a Luneburg lens according to claim 1, characterized in that: The parallel planar waveguide (2) has an electromagnetic wave transition structure (6) at the end of the conductive connection.

4. The waveguide slot antenna array fed by a Luneburg lens according to claim 3, characterized in that: The electromagnetic wave transition structure (6) is a metal inclined structure at the connection point between the end of the parallel planar waveguide (2) and the feed port of the waveguide slot antenna array (4).

5. The waveguide slot antenna array fed by a Luneburg lens according to claim 1, characterized in that: The cylindrical Luneburg lens (3) has an axisymmetric structure and has axisymmetric upper and lower cylindrical surfaces (8). Several small cylindrical units (7) are arranged vertically between the upper and lower cylindrical surfaces (8). The cylindrical surfaces (8) are in close contact with the two metal surfaces of the parallel planar waveguide (2). The small cylindrical units (7) have the same height, and the height is equal to the distance between the upper and lower cylindrical surfaces (8). The small cylindrical units (7) have different radii, and the radius gradually decreases from the center of the cylindrical Luneburg lens (3) to the outer periphery.

6. The waveguide slot antenna array fed by a Luneburg lens according to claim 1 or 5, characterized in that: The cylindrical Luneburg lens (3) is processed using 3D printing technology. The material used for 3D printing is PLA, with a relative permittivity of 3 to 3.

5.

7. The waveguide slot antenna array fed by a Luneburg lens according to claim 1, characterized in that: The waveguide slot antenna array (4) consists of N identical waveguide slot antennas (401), where N≥2; a preset distance is left between adjacent waveguide slot antennas (401) and grooves (9) are engraved; each waveguide slot antenna (401) has M slots (4011) engraved on it, where M≥1; the M slots (4011) are distributed in a crisscross manner on the left and right sides of the central axis of the waveguide slot antenna (401).

8. The waveguide slot antenna array fed by a Luneburg lens according to claim 8, characterized in that: N=7, and the seven identical waveguide slot antennas (401) are arranged linearly.

9. The waveguide slot antenna array fed by a Luneburg lens according to claim 8, characterized in that: M=9, and the nine slots (4011) are arranged at equal intervals along the length of the waveguide slot antenna (401), and the slots (4011) are parallel to the central axis of the waveguide slot antenna (401).

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