A double-layer metal strip array parabolic cylindrical reflector structure of a vehicle-mounted microwave antenna

Abstract

The application relates to a double-layer metal strip array parabolic cylindrical reflector structure of a vehicle-mounted microwave antenna, which comprises a frame structure and a double-layer reflector body, the frame is formed by welding two end base plates, an intermediate supporting plate and transverse supporting rods, and mounting hole positions distributed along a parabola are machined after welding; each layer of the reflector body is formed by fixing a plurality of parallel metal strips, adjacent metal strips are provided with hollow ventilation gaps, the strip spacing and the layer spacing are matched with the antenna working wavelength, and a wave-transparent nylon plate is arranged in the frame to support the metal strips in the radial direction, one end of the metal strip is press-connected and fixed, and the other end is locked by double nuts to provide pre-tightening force. The application has the advantages of low wind resistance, light weight and low cost, is suitable for vehicle-mounted high-mobility working conditions, and guarantees the stable electrical performance of the antenna.

Description

Technical Field

[0001] This invention relates to the field of microwave antenna technology, and specifically to a double-layer metal strip array parabolic columnar reflector structure for a vehicle-mounted microwave antenna. Background Technology

[0002] Reflector antennas are core functional components of microwave communication and radar detection systems. Their working principle involves focusing electromagnetic waves through a specific reflective surface to achieve long-distance signal transmission and high-precision target detection. The surface shape accuracy and structural stability of the reflector directly determine the effective range, detection accuracy, and communication reliability of the entire antenna system. Based on the optical morphology of the reflective surface, reflector antennas mainly include rotating parabolic antennas and parabolic cylindrical reflector antennas. Among them, parabolic cylindrical reflector antennas can convert cylindrical waves radiated from a feed source into parallel beams, combining one-dimensional beam scanning capability with flexible structural layout advantages. They are widely used in mobile communication, emergency command, meteorological detection, traffic monitoring, and other mobile operation platforms.

[0003] Currently, the mainstream reflector antenna technologies in the industry are mainly divided into three categories: aluminum skin sandwich structure, carbon fiber integrated molding structure, and steel cable mesh tension structure.

[0004] Among them, the aluminum-skin sandwich structure reflector uses an aluminum plate as the outer reflector skin, combined with a honeycomb core layer for composite molding. It is shaped as a whole using a special stretching and pressing mold, and has excellent surface accuracy. It is mostly used in fixed communication antenna scenarios. For example, the publications CN101673880B and CN201655975U, "A Manufacturing Method of an Aluminum-Skin Honeycomb Sandwich Structure Antenna Reflector," both use an aluminum plate as the substrate and a mold stretching process to prepare an integrated solid reflector panel. In addition, the publication CN106450791A, "A Large Spatial Parabolic Columnar Rollable Metal Surface Antenna Reflector Structure," uses a whole sheet of thin metal as the reflector substrate, which also belongs to the aluminum-skin parabolic columnar reflector scheme.

[0005] The integrated carbon fiber reflector is formed by molding carbon fiber composite material and back reinforcing ribs together. It features high overall structural rigidity and excellent shape stability in high and low temperature environments, and is mainly used in high-precision fixed detection radar and fixed satellite communication antennas. Conventional carbon fiber antennas use a solid integrated molding process, such as the "A Carbon Fiber Composite Satellite Antenna Reflector with Fusified Back Ribs" published in CN105958211A. To improve wind resistance performance, the "Lightweight Vehicle-Mounted Carbon Fiber Grid Scattering Communication Antenna" published in CN10920738822B further optimizes the structure, adopting a rectangular grid hollowed-out carbon fiber reflector, effectively reducing wind resistance while retaining the integrated molding process.

[0006] The cable mesh reflector is a standard reflective surface formed by stretching a flexible metal cable mesh. Tension is fine-tuned using a cable adjustment device around the antenna to calibrate the surface shape accuracy. Its openwork structure provides good ventilation and is often used in large-aperture fixed satellite receiving antennas. For example, the paper CN119852676A, "An Inflatable Antenna Structure with a Cable Mesh Reflector," uses a stretched metal cable mesh to form the reflective surface, with a cable adjustment device to adjust the surface shape accuracy.

[0007] However, the above three types of reflective surface structures are all developed for fixed base scenarios and cannot be adapted to complex mobile conditions such as high-speed vehicle travel and road bumps and vibrations. In practical applications of vehicle-mounted microwave antennas, they have the following drawbacks:

[0008] (1) The aluminum skin sandwich structure is a fully enclosed solid panel with almost no air permeability, resulting in extremely poor wind load adaptability. Actual operating condition calculations show that when the vehicle platform travels at 40 km / h, the equivalent frontal wind speed at the antenna mounting location can reach 11.1 m / s. The continuous impact and compression of the solid reflector by this high-speed airflow generates wind load, directly inducing elastic deformation of the skin panel, ultimately causing the reflector's surface shape accuracy to deviate from the design calibration value. Once the antenna surface shape accuracy deteriorates, it will trigger a chain reaction of electrical performance problems such as antenna gain attenuation, main lobe broadening, and sidelobe level increase. These problems can range from shortening the effective communication distance and reducing target detection resolution to directly causing wireless signal interruption and radar target misjudgment or missed detection.

[0009] However, from the perspective of actual operational needs, core scenarios such as emergency rescue, comprehensive disaster early warning, and mobile environmental monitoring all require vehicle-mounted antennas to be integrated for both driving and operation, and must remain operational continuously during mobile travel. The electrical performance of these solid panel antennas fluctuates greatly with wind load, resulting in insufficient operational stability. This not only directly reduces on-site operational efficiency and weakens the reliability of wireless data transmission, but also, under extreme conditions, can cause irreversible problems such as interruption of emergency missions and loss of critical environmental monitoring data.

[0010] (2) Although the hollowed-out carbon fiber integrated structure optimizes wind resistance to some extent, it still has structural shortcomings and cost drawbacks. Specifically, the rectangular straight-edged grid structure used in this structure has a relatively high drag coefficient, and both the aluminum skin sandwich structure and the carbon fiber integrated structure require customized special rigid molding molds. The development cost of a single mold is high, and the reflective surfaces of different diameters and focal lengths cannot be used interchangeably, resulting in a low mold reuse rate. This makes it difficult to meet the cost control requirements of multi-model, mass production of automotive equipment.

[0011] (3) The cable mesh reflector is a flexible load-bearing system that relies on the preload of the cable mesh to maintain its shape. Its vibration resistance is unsuitable for vehicle-mounted applications. In other words, the continuous alternating loads from road bumps and engine vibrations during vehicle operation cause fluctuations and attenuation of the cable mesh tension, leading to slack and surface distortion, which compromises the long-term stability of the antenna's electrical performance. Increasing the initial preload to offset vibration would place higher stiffness and load-bearing requirements on the support frame, significantly increasing the weight of the support structure and exceeding the lightweight design limits for vehicle-mounted equipment. Furthermore, the molding, tensioning, and calibration of this structure require specialized molds and tooling, resulting in complex assembly processes, long production cycles, and high manufacturing costs. Moreover, field maintenance and calibration are difficult, making it unsuitable for the rapid deployment and easy maintenance requirements of vehicle-mounted equipment.

[0012] In summary, existing solid skin reflectors have technical drawbacks such as high wind resistance at high speeds, significant wind load deformation, high mass production costs, and excessive assembly weight. Grid-type carbon fiber reflectors have relatively low wind resistance, but the integrated molding of carbon fiber results in high costs, which is not conducive to mass industrialization. Existing flexible steel cable mesh reflectors have technical drawbacks such as weak resistance to alternating vibrations, difficulty in maintaining shape during driving, and a tendency for the supporting structure to exceed weight limits. None of these can simultaneously meet the comprehensive requirements of low wind resistance, lightweight, and low cost for high-mobility vehicle scenarios.

[0013] If we forcibly continue with the existing technological approach, we are forced to choose between two compromises: either sacrifice antenna electrical performance and vehicle safety to adapt to in-vehicle conditions, or strengthen the structure and increase costs to ensure antenna performance. Neither approach can achieve stable and reliable operation of in-vehicle microwave and radar detection systems under high-speed driving conditions. Therefore, there is an urgent need for a new type of parabolic cylindrical reflector structure that can adapt to high-speed in-vehicle driving conditions while also being lightweight and low-cost, in order to solve the above problems. Summary of the Invention

[0014] The purpose of this invention is to address the shortcomings of existing technologies by providing a double-layer metal strip array parabolic columnar reflector structure for vehicle-mounted microwave antennas. This structure can effectively reduce wind resistance during high-speed vehicle operation, while also achieving lightweight design and low-cost mass production, and ensuring the stability of antenna electrical performance under vehicle operating conditions.

[0015] The objective of this invention is achieved through the following approach:

[0016] A double-layer metal strip array parabolic columnar reflector structure for a vehicle-mounted microwave antenna includes a frame structure and a reflector body disposed on the frame structure. The frame structure includes a substrate arranged longitudinally at both ends, at least one intermediate support plate located between the two substrates, and multiple support rods arranged laterally and fixedly connected to the substrates and the intermediate support plate respectively.

[0017] The reflector body includes a front reflector and a rear reflector. Both the front and rear reflectors are confocal parabolic cylinders with the same curvature and aperture parameters. The front and rear reflectors are arranged in a staggered, mutually translated manner along the focal axis of the parabolic cylinder. Each reflector includes several parallel metal strips, with both ends of the metal strips tensioned and fixed to the substrate. Within the same reflector layer, in the aperture section perpendicular to the axis of the metal strips, the center-to-center distance between two adjacent metal strips is no greater than 1 / 7 of the antenna's operating wavelength. Between the front and rear reflectors, the center-to-center distance between the metal strips whose projections coincide along the focal axis is no greater than 1 / 5 of the antenna's operating wavelength.

[0018] Preferably, the substrate is provided with a plurality of mounting holes, and the intermediate support plate includes a plurality of intermediate mounting holes. Each intermediate mounting hole corresponds one-to-one with the mounting holes on the substrate and is coaxially arranged. The support rod passes through the corresponding mounting holes and intermediate mounting holes, and is welded and fixed to the substrate and the intermediate support plate respectively.

[0019] Preferably, a wave-transparent nylon plate is fixedly installed on each intermediate support plate. The wave-transparent nylon plate is provided with positioning holes that correspond one-to-one with the metal strips. The metal strips pass through the corresponding positioning holes and are fixedly connected to the wave-transparent nylon plate by adhesive.

[0020] Preferably, the transparent nylon plate and the intermediate support plate are fixedly connected by rivets, and a clearance groove is provided on the transparent nylon plate to allow the support rod to pass.

[0021] Preferably, one end of the metal strip is provided with a sleeve and is fixed to one side of the substrate by crimping, and the other end of the metal strip is an externally threaded section and is locked to the other side of the substrate by a nut to provide axial preload.

[0022] Preferably, the metal strip is made of 7050 hard aluminum alloy round strip, and after straightening treatment, its straightness is not greater than 0.2mm / m.

[0023] Preferably, each reflective layer on the substrate has mounting holes that are continuously distributed along a parabolic trajectory. The mounting holes are countersunk stepped holes used to accommodate the end fixing structure of the metal strip.

[0024] Preferably, the cross-section of the metal strip is circular, and the perforated ventilation area of ​​the reflective surface body accounts for more than 50% of the total area of ​​the orthographic projection of the reflective surface aperture.

[0025] The beneficial effects of this invention are as follows:

[0026] A double-layer metal strip array parabolic columnar reflector structure for a vehicle-mounted microwave antenna includes a frame structure and a reflector body disposed on the frame structure. The frame structure includes a substrate arranged longitudinally at both ends, at least one intermediate support plate located between the two substrates, and multiple support rods arranged laterally and fixedly connected to the substrates and the intermediate support plate respectively.

[0027] The reflector body includes a front reflector and a rear reflector. Both the front and rear reflectors are confocal parabolic cylinders with the same curvature and aperture parameters. The front and rear reflectors are arranged in a staggered, mutually translated manner along the focal axis of the parabolic cylinder. Each reflector includes several parallel metal strips, with both ends of the metal strips tensioned and fixed to the substrate. Within the same reflector layer, in the aperture section perpendicular to the axis of the metal strips, the center-to-center distance between two adjacent metal strips is no greater than 1 / 7 of the antenna's operating wavelength. Between the front and rear reflectors, the center-to-center distance between the metal strips whose projections coincide along the focal axis is no greater than 1 / 5 of the antenna's operating wavelength.

[0028] This invention replaces the traditional solid skin and tensioned cable mesh reflector structure with a discrete metal strip array, constructing a parabolic columnar reflector architecture of "frame support + double-layer metal strip array reflection". Compared with existing technologies, this solution completely eliminates the dependence on large forming molds. The metal strips can be prepared using standard profiles, and the frame is formed through conventional machining and welding processes, significantly reducing manufacturing costs and production cycles, and adapting to the mass deployment requirements of vehicle-mounted equipment. At the same time, the discretely arranged metal strips form natural hollow ventilation gaps, allowing airflow to pass directly through the reflector, fundamentally reducing wind load during high-speed vehicle operation and effectively avoiding the defects of solid skin structures causing elastic deformation and antenna gain reduction due to strong wind loads. The rigid metal strips are tensioned and fixed by the substrates at both ends. Compared with flexible cable mesh structures, it can stably maintain the parabolic shape without applying extremely high preload, and does not require a heavy-duty reinforcing back frame, achieving a lightweight design from a structural perspective and solving the pain point of traditional cable mesh reflectors being overweight to ensure surface accuracy.

[0029] Furthermore, this invention employs a front and rear double-layer metal strip array. Both the front and rear reflective surfaces are reflective surfaces of the same reference parabolic cylinder, and are arranged in a mutually translated manner along the focal axis of the parabolic cylinder (i.e., the front and rear reflective surfaces are confocal parabolic cylinders with the same curvature and aperture parameters, and are arranged in a staggered, mutually translated manner along the focal axis of the parabolic cylinder). This is achieved by adjusting the center-to-center distance between two adjacent metal strips within the same reflective layer along the parabolic normal direction (i.e., ...). Figure 7The periodic spacing between the front and rear reflectors is controlled to be no greater than 1 / 7 of the antenna's operating wavelength. This size effectively suppresses grating lobe generation, ensures effective reflection of electromagnetic waves in the operating frequency band, and prevents electromagnetic wave leakage and antenna gain reduction caused by excessive spacing. The center-to-center spacing between the metal strips corresponding to the focal axis of the parabolic cylinder between the front and rear reflectors (i.e., ...) Figure 7 The horizontal spacing between the two metal strips is set to be no more than 1 / 5 of the antenna's operating wavelength. This size allows the electromagnetic waves reflected by the two metal strips to form an effective phase superposition. The electromagnetic coupling effect of the two reflective structures compensates for the reflection efficiency loss caused by the hollow structure, enabling the antenna gain and directivity to reach a level comparable to that of the solid skin. This ensures that the electrical performance of the double-layer structure meets the requirements for vehicle-mounted antennas, achieving a balance between low wind resistance, lightweight design, and high performance.

[0030] Preferably, the substrate is provided with a plurality of mounting holes, and the intermediate support plate includes a plurality of intermediate mounting holes. Each intermediate mounting hole corresponds one-to-one with the mounting holes on the substrate and is coaxially arranged. The support rod passes through the corresponding mounting holes and intermediate mounting holes, and is welded and fixed to the substrate and the intermediate support plate respectively.

[0031] This invention utilizes coaxially arranged assembly holes on the base plate and intermediate support plate to achieve pre-positioning of the support rods. After the support rods are inserted into place, they are welded to the plate, forming a stable spatial truss load-bearing system. These coaxial holes constrain the spatial position of the support rods during assembly, eliminating the need for complex tooling clamps and effectively reducing assembly difficulty. This ensures the overall geometric accuracy of the frame and lays the foundation for the precise installation of subsequent metal strips. Simultaneously, multiple support rods connecting the base plate and intermediate support plate evenly distribute wind and vibration loads to each component, avoiding localized stress concentration. This significantly improves the overall stiffness and fatigue resistance of the frame, effectively resisting high-speed wind loads from vehicles and alternating road bumps, and maintaining the surface accuracy of the parabolic cylindrical reflective surface over the long term.

[0032] Preferably, a wave-transparent nylon plate is fixedly installed on each intermediate support plate. The wave-transparent nylon plate is provided with positioning holes that correspond one-to-one with the metal strips. The metal strips pass through the corresponding positioning holes and are fixedly connected to the wave-transparent nylon plate by adhesive.

[0033] This invention utilizes a translucent nylon plate as an intermediate support structure within the frame. This provides multi-point radial support constraints for long-span metal strips, significantly reducing their deflection under wind loads and vibrations. This further enhances the stability of the parabolic surface's shape accuracy and ensures consistent electrical performance under bumpy vehicle conditions. Specifically, the metal strips and positioning holes are fitted with a clearance and secured with adhesive. This ensures assembly feasibility while simultaneously filling gaps and buffering vibrations, preventing collisions and wear between the metal strips and the hole walls. Furthermore, integrating the intermediate support with the metal strips effectively improves the overall structural rigidity and vibration resistance. The translucent nylon material exhibits extremely low electromagnetic wave transmission loss in the operating frequency band, unlike the metal support plate which obstructs the reflection path and interferes with electromagnetic wave reflection. This material-based approach ensures that the electrical performance of the reflecting surface is unaffected by the intermediate support structure.

[0034] Preferably, the transparent nylon plate and the intermediate support plate are fixedly connected by rivets, and a clearance groove is provided on the transparent nylon plate to allow the support rod to pass.

[0035] In this invention, the translucent nylon sheet and the intermediate support plate are fixed together by riveting. This fixing method provides stable connection strength and can be assembled without complex tooling, making it suitable for mass production. The clearance grooves on the translucent nylon sheet effectively avoid structural interference from the transverse support rod, ensuring that the translucent sheet can be accurately installed in the designed position, avoiding assembly failure and surface deviation caused by structural conflicts. The positioning holes and mounting holes are coaxially set, ensuring that there is no additional bending stress after the metal strip is installed, maintaining the straightness accuracy of the metal strip, while reducing assembly difficulty and improving the surface consistency of mass production.

[0036] Preferably, one end of the metal strip is provided with a sleeve and is fixed to one side of the substrate by crimping, and the other end of the metal strip is an externally threaded section and is locked to the other side of the substrate by a nut to provide axial preload.

[0037] For the end fixing of the metal strip, a structure is adopted with an aluminum sleeve crimped at one end and double nuts locking at the other. The crimping process is simple to operate and has high connection reliability, enabling threadless and rapid fixing of the metal strip end. The double nut locking structure has a reliable anti-loosening effect. By controlling the locking torque, the axial preload of the metal strip can be precisely adjusted to straighten the metal strip and maintain a stable tension state. This effectively counteracts the influence of alternating vibration loads during vehicle operation, preventing the metal strip from loosening or bending deformation, and maintaining the parabolic surface accuracy over the long term. At the same time, both fixing structures are adapted to countersunk hole design, which can be completely accommodated inside the aluminum plate without protruding from the outer contour of the reflective surface. This avoids interference with electromagnetic wave radiation by the fixing structure and does not add extra wind resistance, maintaining the low wind resistance characteristics of the structure.

[0038] Preferably, the metal strip is made of 7050 hard aluminum alloy round strip, and after straightening treatment, its straightness is not greater than 0.2mm / m.

[0039] The metal strip described in this invention is made of 7050 hard aluminum alloy profile. This material possesses extremely high strength and rigidity, ensuring structural strength and resistance to deformation while maintaining extremely low self-weight, further enhancing the lightweight advantage of the reflector. Simultaneously, this material exhibits strong weather resistance, making it suitable for use in complex outdoor environments, both in vehicles and outdoors. After straightening and correction, the straightness of the metal strip is no greater than 0.2 mm / m, ensuring the dimensional accuracy of each metal strip at the individual component level. This provides a fundamental guarantee for the surface accuracy of the overall parabolic cylindrical reflector, effectively improving the consistency and stability of the antenna's electrical performance.

[0040] Preferably, each reflective layer on the substrate has mounting holes that are continuously distributed along a parabolic trajectory. The mounting holes are countersunk stepped holes used to accommodate the end fixing structure of the metal strip.

[0041] The mounting holes on the substrate of this invention employ a countersunk stepped hole design, which can fully accommodate the crimp sleeve and locking nut at the end of the metal strip. This ensures that the end fixing structure does not protrude from the outer surface of the substrate. On the one hand, this avoids the additional wind resistance added by the protruding structure, maintaining the low wind resistance characteristics of the reflector. On the other hand, it eliminates the interference of protruding metal components on near-field electromagnetic wave radiation, avoiding problems such as pattern distortion and sidelobe lift, thus ensuring the electrical performance of the antenna. At the same time, the countersunk stepped structure can limit the axial installation position of the metal strip, improving assembly accuracy and consistency, and reducing assembly errors in mass production.

[0042] Preferably, the cross-section of the metal strip is circular, and the perforated ventilation area of ​​the reflective surface body accounts for more than 50% of the total area of ​​the orthographic projection of the reflective surface aperture.

[0043] The metal strip of this invention adopts a circular cross-section rod. According to the drag coefficient characteristics in the load specifications, the drag coefficient of a circular cross-section is much lower than that of rectangular or edge-shaped cross-sections, which can further reduce the force of airflow on the metal strip when the vehicle is traveling at high speed, thus optimizing the drag performance at the component cross-section level. The hollow area of ​​the reflective surface body accounts for more than 50%, which greatly improves the overall air permeability of the reflective surface and directly reduces the windward force area by more than 50%, significantly reducing the wind load and structural deformation during vehicle operation. At the same time, the high hollow area also directly reduces the overall material usage of the reflective surface, further reducing its weight and enhancing the lightweight advantage of vehicle applications. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of the present invention;

[0045] Figure 2This is a schematic diagram of the framework structure of the present invention;

[0046] Figure 3 This is a schematic diagram of the reflective surface structure (assembly connection);

[0047] Figure 4 This is a schematic diagram of the substrate structure;

[0048] Figure 5 This is a schematic diagram of a translucent nylon sheet.

[0049] Figure 6 This is a schematic diagram of the transparent nylon sheet and the intermediate support plate 3;

[0050] Figure 7 This is a schematic diagram of the parabolic cylindrical reflecting surface in this invention. Detailed Implementation

[0051] like Figure 1-7 As shown, this invention discloses a double-layer metal strip array parabolic columnar reflector structure for a vehicle-mounted microwave antenna, comprising a frame structure 1 and a reflector body arranged on the frame structure 1. The frame structure 1 serves as a truss-type load-bearing base, bearing all loads and providing a unified mounting reference for the reflector body.

[0052] The frame structure 1 includes a base plate 7, an intermediate support plate 3, and a support rod 4. Specifically, two parallel base plates 7 are arranged longitudinally symmetrically at both ends of the frame structure 1. The base plate 7 has a number of mounting holes 701 continuously distributed along a parabolic trajectory. The mounting holes 701 are countersunk stepped holes used to accommodate the fixing structures at both ends of the metal strip 6, avoiding the fixing structures from protruding outward, increasing wind resistance, and interfering with electromagnetic wave propagation, thus effectively ensuring the aerodynamic regularity of the reflector surface and the stability of the electromagnetic environment.

[0053] At least one intermediate support plate 3 is provided between the two base plates 7. The intermediate support plate 3 is arranged parallel to the base plates 7 to form a central support for the large-span metal strip 6, improve the structural rigidity of the overall frame, and suppress the bending deformation of the metal strip 6 caused by wind load and vibration.

[0054] The support rods 4 are evenly distributed in the transverse direction, and all support rods 4 are simultaneously fixedly connected to the two side base plates 7 and the intermediate support plate 3. The base plate 7 has a plurality of assembly holes 702, and the intermediate support plate 3 has intermediate assembly holes 301 that are coaxially corresponding to the assembly holes 702 on the base plate 7. The support rods 4 are inserted into the mutually aligned coaxial holes, and the two ends of the support rods 4 and the contact positions of the holes are welded and fixed to the base plate 7 and the intermediate support plate 3, respectively.

[0055] Each intermediate support plate 3 has a wave-transparent nylon plate 2 fixedly mounted on it. Specifically, a limiting step 201 is provided on one side of the wave-transparent nylon plate 2, and the bottom of the intermediate support plate 3 abuts against the limiting step 201. The wave-transparent nylon plate 2 and the intermediate support plate 3 are riveted together by rivets 5, making assembly convenient and the connection stable. A clearance groove 202 corresponding to the position of the support rod 4 is provided on the wave-transparent nylon plate 2 to avoid the support rod 4, eliminate assembly interference, and ensure that the wave-transparent nylon plate 2 can be tightly fitted and fixed to the surface of the intermediate support plate 3. At the same time, positioning holes corresponding one-to-one with the mounting holes 701 of the substrate 7 are provided on the wave-transparent nylon plate 2, and the positioning holes are coaxially aligned with the mounting holes 701 of the substrate 7 to limit and support the middle section of the metal strip 6. Specifically, the wave-transparent nylon plate 2 is made of low-loss wave-transparent nylon material, which has extremely low transmission loss of electromagnetic waves in the working frequency band and will not block the electromagnetic wave reflection path or interfere with the electromagnetic performance of the antenna.

[0056] The reflective surface body is assembled on the frame structure 1 as a whole, including a front reflective surface (i.e., the front reflective layer) and a rear reflective surface (i.e., the rear reflective layer). The front reflective surface and the rear reflective surface are both reflective surfaces of the same reference parabolic cylinder. The focal length, curvature and aperture parameters of the two reflective surfaces are completely consistent. They are arranged to be translated relative to each other only along the focal axis of the parabolic cylinder to form a double-layer staggered hollow reflective structure.

[0057] Specifically, both the front and rear reflective surfaces are composed of an array of parallel metal strips 6. The ends of all metal strips 6 are tensioned and fixed to mounting holes 701 on the two side substrates 7. The generatrices of all metal strips 6 on the same side within the same reflective layer are fitted together to form a complete parabolic cylindrical reflective surface. Natural ventilation gaps are formed between adjacent metal strips 6, allowing airflow to directly penetrate the reflective surface, thus reducing the wind load on the road during high-speed vehicle operation.

[0058] To balance structural mechanical and electromagnetic performance, this invention precisely limits the spacing of the metal strip array 6: within the same reflective layer, the center-to-center distance between two adjacent metal strips 6 along the parabolic normal direction is no greater than 1 / 7 of the antenna's operating wavelength, which effectively suppresses grating lobe generation, prevents electromagnetic wave leakage, and ensures the basic reflection efficiency of the single-layer hollow array; between the front and rear reflective surfaces, the center-to-center distance between the corresponding metal strips 6 along the focal axis of the parabolic cylinder is no greater than 1 / 5 of the antenna's operating wavelength, thereby providing a structural basis for the phase superposition and electromagnetic coupling gain of the double-layer reflected electromagnetic waves and compensating for the reflection efficiency loss of the hollow structure.

[0059] The metal strip 6 passes through the mounting holes 701 of the substrate 7 and the positioning holes of the transparent nylon plate 2, forming a fully constrained structure with fixed ends and a central support. Specifically, the metal strip 6 adopts a differentiated two-end fixing structure: one end of the metal strip 6 is fitted with an aluminum sleeve 9, which is pressurized to deform and form an interference fit with the metal strip 6, and the sleeve is press-fitted and fixed in the countersunk stepped hole of one side of the substrate 7; the other end of the metal strip 6 is machined with an external thread section, which passes through the countersunk stepped hole of the other side of the substrate 7 and is locked and fixed by a pair of double nuts 8. By adjusting the locking torque of the double nuts, the axial preload of the metal strip 6 can be precisely controlled, so that the metal strip 6 can be kept in a straight and taut state for a long time, resisting the loosening and bending deformation of the rod caused by vehicle bumps and vibrations and wind loads.

[0060] The positioning holes of the metal strip 6 and the transparent nylon plate 2 are assembled with a clearance fit. After assembly, the gaps in the holes are filled with adhesive and cured at room temperature, so that the metal strip 6 and the transparent nylon plate 2 are fixed together as one, forming multi-point radial support for the metal strip 6. This can effectively limit the radial vibration and bending deformation of the middle section of the metal strip 6 and continuously and stably maintain the accuracy of the parabolic surface shape.

[0061] Metal strip 6 is made of 7050 hard aluminum alloy round strip profile. After precision straightening treatment, the straightness of the rod is no more than 0.2mm / m, which can effectively ensure the shape and position accuracy of a single rod and provide a foundation for accurate fitting of the parabolic surface shape. In this invention, metal strip 6 adopts a circular cross-section design, which has a lower drag coefficient and is suitable for complex vehicle-mounted operating conditions; at the same time, the overall hollow area of ​​the reflective surface is greater than 50% of the total area, which reduces wind load and material usage, achieving structural lightweighting.

[0062] The working principle of the above structure is as follows:

[0063] The structure described in this invention utilizes the optical properties of a parabolic cylindrical surface and a dual-layer array electromagnetic coupling mechanism to effectively achieve a comprehensive effect of low wind resistance, lightweight, high precision, and high electrical performance.

[0064] (1) The reflecting surface described in this invention follows the standard parabolic cylindrical equation:

[0065]

[0066] In the formula, Let be the longitudinal coordinate of any point on the parabolic surface; Let x be the x-coordinate of any point on the parabolic surface; The focal length of the parabolic cylinder is the distance from the vertex of the parabola to the focal point of the electromagnetic wave. The antenna feed is precisely positioned at this focal point.

[0067] The mounting holes 701, precisely arranged along the parabolic trajectory on the substrate 7, ensure that all metal strips 6 are arranged strictly according to the standard parabolic cylindrical curve, accurately fitting the designed surface, enabling the antenna to have the basic ability to focus and transmit electromagnetic waves and receive them, thus ensuring the accuracy of the basic surface shape and electromagnetic performance.

[0068] (2) For example Figure 7 As shown, this invention employs a confocal, double-layered hollow metal strip array structure with staggered front and rear along the focal axis. During operation, the feed source is positioned at the common focal point of the parabolic cylinder, radiating cylindrical electromagnetic waves outwards. These electromagnetic waves propagate towards the reflecting surface along the focal axis. When the electromagnetic wave is incident on the front layer of the metal strip array, the strips typically achieve effective reflection. Only under special conditions such as vehicle bumps or instantaneous structural vibrations, some electromagnetic waves may leak from the gaps in the front layer and continue propagating to the rear reflecting surface. The rear metal strips then perform secondary reflection of the leaked waves, forming a redundant protection mechanism. Since both reflecting surfaces share the same focal point, the electromagnetic waves reflected by the front and rear layers respectively exit along a direction parallel to the focal axis, forming a planar wavefront and ensuring that the focusing characteristics of the reflecting surface remain unchanged.

[0069] For single-layer perforated reflective arrays, when the spacing between the metal strips exceeds half the operating wavelength, significant grating lobes are generated, resulting in a decrease in main lobe gain and an increase in side lobe level. This invention controls the center-to-center spacing of adjacent metal strips within the same layer to within 1 / 7 of the operating wavelength, far below the critical spacing for grating lobe generation. This effectively suppresses the generation of higher-order grating lobes, prevents electromagnetic wave energy leakage through the perforated gaps in the operating frequency band, and ensures the basic reflection efficiency of the single-layer array.

[0070] Based on this, the center distance between the front and rear metal strips along the focal axis is controlled within 1 / 5 of the working wavelength. By precisely controlling the propagation path difference of the two reflected waves, when leakage occurs and both layers participate in reflection simultaneously, the electromagnetic wave reflected by the rear layer and the electromagnetic wave directly reflected by the front layer form in-phase superposition in the far field. Gain compensation is generated through the electromagnetic coupling effect of the double-layer array, which effectively makes up for the reflection efficiency loss caused by insufficient metal ratio or structural vibration in the single-layer hollow structure. Ultimately, the gain, radiation pattern and other electrical performance indicators of the double-layer hollow reflective surface reach a level comparable to that of the traditional solid skin reflective surface.

[0071] The processing flow of the above structure is as follows:

[0072] 1) The substrate 7, intermediate support plate 3, and support rod 4 are cut and processed according to the design dimensions. The assembly holes 702 and mounting holes 701 of each plate are processed by CNC equipment. After positioning with tooling, the support rod 4 is inserted into the coaxial hole and welded to form the overall frame blank.

[0073] 2) Perform overall CNC precision machining on the welded frame blank to correct welding deformation, precisely machine the parabolic trajectory mounting holes 701 on the substrate 7, form a countersunk stepped structure, and ensure the hole position accuracy and surface reference accuracy.

[0074] 3) Machining clearance grooves 202 and positioning holes for metal strips 6 on the transparent nylon plate 2, calibrating the coaxiality of the positioning holes and mounting holes 701 of the substrate 7 using special tooling, and using rivets to firmly rivet the transparent nylon plate 2 to the surface of the intermediate support plate 3.

[0075] 4) Straighten the metal strip 6, press one end to fix the aluminum sleeve, process the external thread on the other end, and insert the metal strip 6 into the holes of the substrate 7 and the transparent nylon plate 2 in sequence. Tighten by locking with double nuts to ensure that all metal strips 6 are tensioned evenly and the rods are straight.

[0076] 5) Fill the gap between the positioning hole of the transparent nylon plate 2 and the metal strip 6 with adhesive. After the adhesive has completely cured at room temperature, the metal strip 6 and the transparent nylon plate 2 will form an integral support structure, and the overall assembly of the device will be completed.

[0077] It is important to note that during assembly, the coaxiality and parallelism accuracy of each hole must be strictly controlled to avoid hole deviations causing the metal strip 6 to skew, which would affect the overall parabolic surface accuracy. The tensioning preload of the metal strip 6 must be uniform to prevent local stress concentration from causing deformation of the rod and distortion of the surface. The adhesive must completely fill the gaps between the holes to eliminate gaps and prevent the metal strip 6 from shaking and wearing under vehicle vibration conditions. During assembly, the surface accuracy of both the front and rear reflective surfaces must meet RMS≤2mm to ensure the long-term stable electromagnetic performance of the antenna.

[0078] Example 1

[0079] This embodiment is a standard and complete configuration adapted to conventional vehicle-mounted microwave communication antennas, and is the most typical and versatile preferred implementation of the present invention.

[0080] In this embodiment, the double-layer reflectors are staggered along the focal axis of the parabolic cylinder. Both reflectors share the same parabolic cylindrical reference, with identical focal length and aperture parameters. The rear reflector effectively shields the leakage wave at the hollowed-out position of the front layer, improving the antenna's directivity and anti-interference capability. The device can operate stably in a wide temperature range of -40℃ to +65℃, adapting to vehicle driving conditions of 40km / h and an equivalent oncoming wind speed of 11.1m / s. The metal strip 6 is made of 7050 hard aluminum alloy profile, with a straightness of no more than 0.2mm / m after straightening. The hole machining accuracy is high, and the surface shape accuracy of the assembled reflector is RMS≤2mm, fully meeting the requirements of conventional vehicle-mounted microwave antennas. This embodiment fully adopts all the above-described structures, assembly processes, and electromagnetic working principles of this invention, resulting in a complete structure, stable performance, and coverage of most conventional vehicle-mounted microwave antenna application scenarios.

[0081] Example 2

[0082] This embodiment is designed for small-to-medium aperture vehicle-mounted microwave antennas. The double-layer reflective structure, metal strip 6 array parameters, electromagnetic working principle, processing and assembly process of this embodiment are consistent with those of Embodiment 1. Only the structural characteristics of small-to-medium aperture reflective surface with small span and sufficient rigidity of metal strip 6 itself are taken into account, and the support structure configuration is simplified. Only a single intermediate support plate 3 and a corresponding wave-transparent nylon plate 2 are set between the two substrates 7, and the number of support rods 4 is reduced at the same time. Under the premise of fully ensuring the parabolic surface accuracy, structural stability and electromagnetic performance, the components are simplified and the overall weight and processing and manufacturing costs are reduced.

[0083] Example 3

[0084] This embodiment describes the reflector structure adapted for a vehicle-mounted C-band microwave antenna. In this embodiment, the effective axial length of the parabolic cylinder is 6000mm, the aperture width is 2600mm, and the focal length of the parabolic surface is 2200mm. The thickness of the substrate 7 is 40mm, the thickness of the intermediate support plate 3 is 15mm, and six 6061 aluminum alloy support rods 4 of different specifications are configured. The substrate 7 is provided with 17 sets of mounting holes 702, and the intermediate support plate 3 has corresponding coaxial holes. After the frame is welded and precision-machined, the positional tolerance of the holes is ≤0.05mm.

[0085] The wave-transparent nylon plate 2 is made of glass fiber reinforced nylon with a dielectric constant ≤3.0 and a coaxiality tolerance of ≤0.1mm between the positioning hole and the mounting hole 701 of the substrate 7.

[0086] Each reflector layer is equipped with 220 7050-T6 hard aluminum alloy metal strips 6 with a diameter of 3mm. The center-to-center distance between adjacent metal strips 6 in the same layer is 8.5mm, which is less than 1 / 7 of the antenna's operating wavelength (approximately 8.57mm). The horizontal center-to-center distance between corresponding metal strips 6 in the front and rear layers is 12.5mm, which is less than 1 / 5 of the antenna's operating wavelength (approximately 12.6mm).

[0087] After crimping, the pull-out force of metal strip 6 is no less than 500N, and the locking torque of the double nuts is controlled between 0.8 and 1.2 Nm. The adhesive is cured at room temperature for 24 hours. In this embodiment, the perforation rate of the reflective surface reaches 52%, which can reduce the wind load by 56%. The surface shape accuracy is stable under high-speed vehicle driving conditions, and the electromagnetic performance is excellent, which can effectively adapt to the scenario of large-aperture, high-performance vehicle-mounted C-band antennas.

[0088] Meanwhile, calculations show that for microwave antennas of the same specifications, the projected surface size of the reflector (e.g., length × width = 6 meters × 3.5 meters = 21 square meters) would require an estimated investment of up to 840,000 yuan when using a traditional carbon fiber reflector, based on the market price of approximately 40,000 yuan per square meter for carbon fiber molds. In contrast, the structure described in this invention does not require the customization of large curved surface forming molds, which significantly reduces the cost of mass production.

[0089] In summary, the structure of this invention ensures overall rigidity and surface stability through the frame structure 1, solves the problem of electromagnetic performance interference from intermediate supports through the low-loss transparent support structure, and achieves electromagnetic coupling gain through precise double-layer array spacing parameters. This effectively balances the core requirements of vehicle-mounted antennas: low wind resistance, lightweight, high precision, low cost, and high electrical performance. Furthermore, the structure of this invention can be flexibly adapted and optimized according to antenna aperture and operating frequency band, exhibiting strong versatility and engineering adaptability. The manufacturing process is simple, requiring no custom-made molds, and is suitable for mass production, possessing extremely high value for widespread application.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. A double-layer metal strip array parabolic columnar reflector structure for a vehicle-mounted microwave antenna, comprising a frame structure (1) and a reflector body disposed on the frame structure (1), characterized in that: The frame structure (1) includes a base plate (7) arranged longitudinally at both ends, at least one intermediate support plate (3) located between the two base plates (7), and multiple support rods (4) arranged laterally and fixedly connected to the base plate (7) and the intermediate support plate (3) respectively. The reflector body includes a front reflector and a rear reflector. Both the front and rear reflectors are confocal parabolic cylinders with the same curvature and aperture parameters. The front and rear reflectors are arranged in a staggered manner along the focal axis of the parabolic cylinder. Each reflector includes several parallel metal strips (6). The two ends of the metal strips (6) are tensioned and fixed on the substrate (7). In the same reflector layer, in the aperture section perpendicular to the axis of the metal strip, the center distance between two adjacent metal strips (6) is not greater than 1 / 7 of the antenna's operating wavelength. Between the front and rear reflectors, the center distance between the metal strips (6) that project along the focal axis is not greater than 1 / 5 of the antenna's operating wavelength.

2. The double-layer metal strip array parabolic columnar reflective surface structure according to claim 1, characterized in that, The substrate (7) is provided with a plurality of mounting holes (702), and the intermediate support plate (3) includes a plurality of intermediate mounting holes (301). Each intermediate mounting hole (301) corresponds to the mounting hole (702) on the substrate (7) and is coaxially arranged. The support rod (4) passes through the corresponding mounting hole (702) and the intermediate mounting hole, and is welded and fixed to the substrate (7) and the intermediate support plate (3) respectively.

3. The double-layer metal strip array parabolic columnar reflective surface structure according to claim 1, characterized in that, A transparent nylon plate (2) is fixedly installed on each intermediate support plate (3). The transparent nylon plate (2) is provided with positioning holes corresponding to the metal strip (6). The metal strip (6) passes through the corresponding positioning hole and is fixedly connected to the transparent nylon plate (2) by adhesive.

4. The double-layer metal strip array parabolic columnar reflective surface structure according to claim 3, characterized in that, The transparent nylon plate (2) and the intermediate support plate (3) are fixedly connected by rivets. A clearance groove (202) is provided on the transparent nylon plate (2) to avoid the support rod (4).

5. The double-layer metal strip array parabolic columnar reflective surface structure according to claim 1, characterized in that, One end of the metal strip (6) is provided with a sleeve and is fixed to one side of the base plate (7) by crimping. The other end of the metal strip (6) is an external thread section and is locked to the other side of the base plate (7) by a nut to provide axial preload.

6. The double-layer metal strip array parabolic columnar reflective surface structure according to claim 1, characterized in that, The metal strip (6) is made of 7050 hard aluminum alloy round strip profile, and after correction and straightening treatment, its straightness is not greater than 0.2mm / m.

7. The double-layer metal strip array parabolic columnar reflective surface structure according to claim 1, characterized in that, The substrate (7) has mounting holes (701) that are continuously distributed along a parabolic trajectory for each reflective layer. The mounting holes (701) are countersunk stepped holes used to accommodate the end fixing structure of the metal strip (6).

8. The double-layer metal strip array parabolic columnar reflective surface structure according to claim 1, characterized in that, The cross-section of the metal strip (6) is circular, and the perforated ventilation area of ​​the reflective surface body accounts for more than 50% of the total area of ​​the orthographic projection of the reflective surface aperture.

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