Sectional integrated assembly skin stealth antenna process method

Abstract

The invention discloses a process method for integrally assembling a skin stealth antenna in a sectional mode, and relates to the technical field of antennas. The method comprises the following steps of: firstly, dividing a designed curved-surface skin antenna into N sections of which N is greater than or equal to 2, and then dividing each divided section of the antenna into two sections, namely a left section and a right section from the position of a transverse center line of a curved-surface arc top; in the longitudinal and transverse directions of the air back cavity radio frequency functional layer below the left and right sections of skins, a Balun structure is used as a bridge to connect the radiation metal pattern, curved surface circuit plane manufacturing and skin curved surface conformal assembly are realized, and automatic assembly and communication of the circuit on the curved surface are completed by means of the healing process of a fixing tool and a self-healing conductive material; and finally, assembling N sections of antennas to obtain a complete skin antenna. According to the invention, the integrated assembly manufacturing of the skin antenna bearing body, the metal pattern and the Balun structure is realized by utilizing the processes of structure segmentation, step-by-step assembly, integrated assembly and the like, and the integrated assembly of the reconfigurable radio frequency front-end assembly through the feed point in the Balun structure can also be realized.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to a process method for assembling a segmented integrated skin stealth antenna. Background Art

[0002] Traditional antennas are installed on the nose or other locations of aircraft by mechanically punching holes because they protrude from the surface of the airborne platform. This increases the radar cross-section of the aircraft, which not only seriously affects the aerodynamic performance of the aircraft, but also easily leads to a decrease in stealth performance. The additional antenna support structure and auxiliary facilities have greatly increased the weight, complexity, cost and space occupied by the aircraft. The independent installation mode of the antenna and the holes in the aircraft skin have led to a larger fuselage, shorter standby time in the air, reduced survivability, and increased repair and maintenance costs for the fuselage structure. Therefore, it is difficult for traditional antennas to adapt to the functional requirements of a new generation of aircraft.

[0003] To this end, the skin antenna directly uses a low-profile and easy-to-fold microstrip antenna array to achieve conformity with the platform, avoiding the back-and-forth reflection of electromagnetic waves between the radome and the antenna array in traditional conformal antennas, and achieving better stealth performance. The skin antenna is an antenna or antenna array that conforms to the fuselage and is integrated into the aircraft's skin, making it both a structural component and an electronic device. The antenna and the surface structure of the aircraft body are seamlessly and smoothly integrated, which can eliminate many defects of traditional airborne antennas. At present, skin technology is in a rapid development stage, and the main research focuses on the overall architecture, antenna, T / R, RF channel, preprocessing, packaging, structural process manufacturing, thermal management, etc.

[0004] Limited by the current traditional printed circuit board processing, structural parts machining and other process capabilities, the skin antenna manufacturing process is difficult to break through, which has become the main technical bottleneck in the development of skin antennas. Therefore, new process technologies need to be introduced. Additive manufacturing is an effective way to solve the problem of integrated manufacturing of skin antennas. Based on metal 3D printing technology and inkjet 3D printing technology, the curved integrated manufacturing of skin carriers and circuit functions can be realized. At the same time, the composite application of 3D printing process technology can break through key technologies such as curved conformal circuit manufacturing and micro-structure three-dimensional manufacturing, realize the integrated integrated manufacturing of skin carrier structures and functional configurations such as radio frequency sensors and system thermal control, and realize the integrated integration with microsystem modules through the later three-dimensional assembly, and finally realize the whole machine manufacturing of intelligent skin antennas. Summary of the invention

[0005] The purpose of the present invention is to propose a segmented integrated assembly process method for skin antennas based on the new technical characteristics of multifunctional radio frequency skins, which can realize the segmented and step-by-step integrated assembly of skin antennas, while meeting the manufacturing precision requirements and solving the antenna stealth requirements.

[0006] In order to achieve the above-mentioned object of the present invention, the present invention provides a segmented integrated assembly process method of a skin antenna, comprising the following steps: Step 1: Use simulation software to design the required curved skin antenna; realize the conformity of the low-profile and easy-to-fold microstrip antenna array and the skin antenna; the curved skin antenna has an array-arranged protruding balun structure on the inner concave surface of the curved surface, and an array-arranged radiation metal pattern connected by the balun structure as a bridge, and an array-arranged metal pattern on the outer convex surface of the curved surface; Step 2: According to the curved skin antenna designed in step 1, a skin carrier with the same curvature is obtained, and the skin carrier is divided into N sections, where N ≥ 2; Step 3: Divide each segmented skin carrier into a left skin carrier and a right skin carrier from the transverse centerline position of the curved arc top; Then, 3D printing or mechanical processing is used to process N left and right sections of skin carriers, and array-arranged balun structures and radiation metal patterns are manufactured on the inner surface of the skin carrier, and metal patterns are prepared on the outer surface to obtain a skin carrier with an antenna curved circuit attached to the surface; Step 4: Use the designed curved skin antenna positioning tool to place the left and right skin carriers of the same section in the positioning tool, use the fixing tool to align and install the left and right skin carriers according to the metal pattern, and after positioning and installation, use the foaming agent to fill the curved grooves of the assembled left and right skin carriers. After the foaming agent is foamed and cured, the fixing tool and the self-healing conductive material are used to perform the healing process, completing the automatic assembly and connection of the circuit on the curved surface of the skin; Step 5: After completing the positioning and assembly of the N segmented left and right skin carriers in sequence, use the positioning tooling and foaming agent to complete the foaming and fixation of the N segmented antennas, assemble the N segmented antennas into a complete skin antenna, and finally realize the integrated integration of the skin antenna.

[0007] Furthermore, when the antenna is segmented, it is necessary to avoid dividing the surface metal pattern into two.

[0008] Furthermore, the radiant metal patterns are regularly arranged along the longitudinal and transverse directions on the inner concave surface; and the metal patterns are zigzag metal patterns.

[0009] Furthermore, the paper cutting technology is used to cut and prepare the radiant metal pattern with multiple interpenetrating network structures with the help of tools.

[0010] Furthermore, the skin carrier substrate is specifically polyetheretherketone, polyimide, polymethacrylimide or other non-metallic materials, aluminum alloy or other metal materials.

[0011] Furthermore, a low-profile back cavity of a conformal skin antenna is designed based on HFSS software. The feeding and impedance matching are carried out through a coaxially connected gradient microstrip line. The microstrip line coupling gap radiates energy, and then a parallel branch is added at the antenna feeding position as a standing wave debugging. An open-circuit microstrip branch is introduced into the feeding network. By changing the branch length, the antenna frequency can be adjusted without changing other parameters of the antenna. The antenna is tightly combined with the skin to achieve conformal installation of the antenna.

[0012] Furthermore, the balun structure includes a balun, which is a balanced-unbalanced converter. The insulated copper wire on the coaxial cable or the non-magnetic core is neatly wound around a cylinder as a skeleton magnetic material and fixed thereon to make a balun with a use range of 3.5-7Mhz multiplication. Through two sets of mutually isolated coils, the matched input is converted into a differential output in dB units, thereby realizing the conversion from balanced to unbalanced.

[0013] Furthermore, the balun structure is a bridge connecting at least three rows of radiating metal patterns to form a radiating unit of the antenna feeding network in the shape of a turtleback feed point grid.

[0014] Furthermore, the process of automatically assembling and connecting the circuit on the skin surface is specifically as follows: Check the alignment of the zigzag metal patterns on the surfaces of the left and right skin carriers. If the alignment is accurate, use the electrical assembly process to apply conductive glue at the docking position of the zigzag metal patterns and the radiant metal patterns of the left and right skin carriers to complete the closed interconnection of the zigzag metal patterns and the radiant metal patterns. If the alignment is inaccurate, use a scalpel to clean part of the foaming agent, and then reuse the foaming agent to foam, and re-position and assemble until the positioning is accurate, and then use conductive glue to close and interconnect the docking position of the zigzag metal patterns and the radiant metal patterns of the left and right skin carriers.

[0015] Furthermore, the conductive adhesive is specifically a conductive silver paste or a self-healing conductive material based on conductive nano-Ag powder and polycaprolactone polymer.

[0016] Compared with the prior art, the present invention has the following advantages: The present invention proposes a segmented integrated assembly process for skin antennas for the first time, and utilizes innovations in structural segmentation design, step-by-step assembly process methods, and integrated assembly process to achieve integrated assembly and manufacturing of skin antenna carriers, metal graphics, and balun structures. It can also achieve integrated assembly of reconfigurable RF front-end components through the feed points in the balun structure. Compared with traditional skin antenna and phased array antenna integrated assembly processes, the present invention also has the technical advantages of high integration, high stealth performance, low cost, and multi-function.

[0017] The present invention can not only realize the integrated manufacturing of the skin antenna metal pattern and the balun structure, but also realize the integrated assembly with the reconfigurable radio frequency front-end component through the feed point in the balun structure.

[0018] The present invention is particularly suitable for a new generation of skin antennas, and can significantly improve the functional performance of aircraft, especially stealth performance. The specific technical effects are further described in the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the process of forming a reconfigurable radio frequency front-end component by segmenting the antenna skin of the present invention.

[0020] Figure 2 It is a schematic diagram of the positioning and assembly tooling for the curved skin antenna.

[0021] Figure 3 It is a coordinate diagram with the help of coordinate transformation.

[0022] In the figure: 1. left skin carrier, 2. right skin carrier, 3. round metal pattern, 4. radiation metal pattern, 5. balun structure, 6. positioning tool, 7. positioning tool, 8. foaming agent. DETAILED DESCRIPTION

[0023] The present invention provides a process method for assembling a segmented integrated skin stealth antenna, comprising the following steps: Step 1: Design the required curved skin antenna, use HFSS software for simulation analysis, and achieve the conformity of the low-profile and easy-to-fold microstrip antenna array and the skin antenna; specifically, the designed curved skin antenna is as follows Figure 3 As shown, the inner concave surface of the skin antenna has an array of balun structures, and the array of radiation metal patterns 4 is connected by the protruding balun structure 5 as a bridge, and the outer convex surface of the curved surface has an array of zigzag metal patterns 3, as shown in FIG. Figure 1 As shown; further, the radiation metal pattern 4 is regularly arranged along the vertical and horizontal directions on the inner concave surface.

[0024] Furthermore, the configuration transformation characteristics of the smooth rolling paper-cutting technology (kirigami) are used to unfold the complex curved circuit to a plane through dimensionality reduction mapping, and a reconfigurable model of a subarray unit is constructed. Then, on the skin carrier substrate, a dot matrix conformal array structure with no less than two radiation units arranged regularly or randomly is printed, and an array panel with radiation characteristics is obtained through appropriate excitation. By setting antenna unit mounting interfaces distributed according to a certain rule on the array panel, a spherical patch that constitutes the vector sum of the radiation field of each unit of the antenna array is formed, and conformal covering of the regularly arranged antenna units is achieved, thereby realizing the antenna function of conformal coverage; Since each subarray unit can adopt the directional pattern reconfiguration technology, according to the reconfigurable model of the subarray unit, with the help of coordinate transformation, the calculation formula of the unit subarray is added. , assuming that the initial position of the unit antenna is at the origin of the coordinate system, and the phase of the far-field radiation pattern of the unit antenna is (θ, φ), then the path difference r between the two positions along the (θ, φ) direction, the phase difference Δφ=360∗r / λ0, is the array factor of the binary array.

[0025] Among them, f(θ, φ) is the directivity function of the array element; farr(θ, φ) is the array factor; θ is the phase of the far-field radiation pattern of the unit antenna, φ is the changing phase of the far-field radiation pattern of the unit antenna, and λ0 is the wavelength at the operating frequency of the antenna.

[0026] A low-profile back cavity of a conformal skin antenna is designed. Feeding and impedance matching are performed through a coaxially connected gradient microstrip line. The microstrip line coupling gap radiates energy, and then a parallel branch is added at the antenna feeding position as a standing wave debugging; an open-circuit microstrip branch is introduced into the feeding network, and the antenna frequency is adjustable by changing the branch length without changing other antenna parameters; the antenna is tightly combined with the skin to achieve conformal installation of the antenna; the antenna structural parameters are adjusted according to the simulation results to achieve the best working performance; the actual antenna array is made according to the simulation results, and tested in actual environment to verify the design effect.

[0027] Through the above steps, the conformality of a low-profile and easily foldable microstrip antenna array and a skin antenna can be achieved to meet specific application requirements.

[0028] Furthermore, the balun in the balun structure 5 is a balanced-unbalanced converter, which is made by neatly winding the insulated copper wire on the coaxial cable or the non-magnetic core around the cylindrical frame magnetic material and fixing it, so as to make a balun with a use range of 3.5-7Mhz multiplication. Through two sets of mutually isolated coils, the matched input is converted into a differential output in dB, thereby realizing the conversion from balanced to unbalanced.

[0029] Step 2: Based on the curved skin antenna designed in step 1, obtain a skin carrier with the same curvature and divide it into N sections (N ≥ 2). Figure 3 N=4; when the antenna is segmented, consideration should be given to avoiding the situation where the surface metal pattern between each antenna segment is divided into two. This is because it is very difficult to achieve closed interconnection of the metal patterns between each antenna segment. Even if closed interconnection can be achieved, it will have a huge negative impact on the stealth performance of the antenna.

[0030] Step 3: Divide each segment of the (N segments) antenna into two segments from the horizontal centerline position of the top of the curved surface, into left and right segments: left skin carrier 1 and right skin carrier 2; the purpose of this is to enable the use of 3D printing technology to complete the processing and manufacturing of the balun structure 5 and the zigzag metal pattern 3 and the radiation metal pattern 4 of the inner groove of the antenna, but since the zigzag metal pattern 3 and the radiation metal pattern 4 must be present at the top of the curved surface antenna, it is inevitable to divide the zigzag metal pattern 3 and the radiation metal pattern 4 into two; The base material of the skin carrier can be made of non-metallic materials such as polyetheretherketone PEEK, polyimide PI, polymethacrylimide PMI, etc., or metal materials such as aluminum alloy.

[0031] Then, 3D printing or mechanical processing methods are used to process N left and right skin carriers, mainly processing left and right skin carriers, balun structures 5, radiation metal patterns 4 on the inner surface of the skin, and curved metal patterns 3 on the outer surface of the skin. The balun structure 5 is used as a bridge to connect at least three rows of radiation metal patterns 4 to form a tortoise-back feed point grid-shaped antenna feed network radiation unit, realizing the plane manufacturing of the curved circuit and the conformal assembly of the skin surface; specifically, the kirigami technology is used to cut and prepare the radiation metal pattern 4 with multiple interpenetrating network structures with the help of tools. Figure 3 As shown, the upper right corner of the figure is a partial enlarged view of the final product of the skin antenna. It can be seen that the balun structure 5 is perpendicular to the skin carrier and arranged in an array.

[0032] Step 4: Figure 2 As shown, the designed curved skin antenna positioning fixture 6 is used to place the left and right skin carriers of the same section in the positioning fixture 6, and the left skin carrier 1 and the right skin carrier 2 are aligned and installed according to the skin surface pattern using the positioning tool 7. The positioning tool 7 can be a high-temperature tape. After the positioning and installation are completed, a two-component foaming agent 8 (such as polyurethane, etc.) is used, mixed evenly according to a 1:1 combination, and poured and filled in the curved surface grooves of the assembled left and right skin carriers. After the foaming agent 8 is foamed and cured, the positioning tool 7 and the self-healing conductive material are used to perform a healing process, thereby completing the automatic assembly and connection of the circuit on the curved surface of the skin. Specifically, check the alignment of the left and right skin carriers. If the alignment is accurate, use the electrical installation process to apply conductive silver paste or self-healing conductive material based on conductive nano-Ag powder and polycaprolactone (PCL) polymer on the butt joint of the zigzag metal pattern 3 and the radiant metal pattern 4 of the left and right skin carriers to complete the closed interconnection of the zigzag metal pattern 3 and the radiant metal pattern 4. If the alignment is inaccurate, use a scalpel to clean part of the foaming agent 8, and then repeat the foaming, re-position and assemble, until the positioning is accurate, and then use conductive glue to close and interconnect the butt joint of the zigzag metal pattern 3 and the radiant metal pattern 4 of the left and right skin carriers.

[0033] This self-healing conductive material based on conductive nano-Ag powder and polycaprolactone (PCL) polymer can exhibit excellent electrical properties and mechanical strength. At temperatures above 80 °C, it can show an extremely high performance recovery rate. When the Ag content is 80%, the conductivity recovery rate can reach 90%. At the same time, the self-healing conductive material also has excellent processability. The self-healing circuit prepared by means of coordinate transformation and patterned cutting can achieve high alignment on the curved surface, thereby ensuring the stability and smoothness of the circuit connection. It should be noted that the thickness of the conductive glue should be kept consistent with the thickness of the circular metal pattern 3 and the radiating metal pattern 4 as much as possible to avoid affecting the stealth performance; for spherical patches, the width should be less than 0.28R.

[0034] Step 5: After completing the positioning and assembly of the N segmented left and right skin carriers in sequence, use the positioning tool 6 and the foaming agent 8 to complete the foaming and fixing of the N segmented antennas, assemble the N segmented antennas into a complete skin antenna, and finally realize the integrated integration of the skin antenna.

[0035] The present invention utilizes innovative design of structural segmentation, step-by-step assembly process methods and integrated assembly processes to achieve integrated assembly and manufacturing of antenna skin carrier, metal graphics and balun structure, and can also realize reconfigurable RF front-end components, and integrate and assemble conformal antennas through the feed points in the balun structure. This skin antenna directly adopts a low-profile and easy-to-fold microstrip antenna array to achieve conformality with the platform, avoiding the back and forth reflection of electromagnetic waves between the antenna cover and the antenna array in traditional conformal antennas, and can achieve better stealth performance. Due to the segmented integrated assembly process method of the skin antenna, the segmented and step-by-step integrated assembly of the skin antenna can be achieved. Compared with the traditional skin antenna and phased array antenna integrated assembly process, the conformal antenna can reduce interference with the surface shape of the carrier while maintaining good radiation performance. In addition to its technological advancement, the present invention also has the technical advantages of high integration, high stealth performance, low cost and multi-function.

[0036] When the antenna of the present invention is segmented, consideration is given to avoiding the situation where the metal pattern is divided into two between each antenna segment. This is because it is very difficult to achieve the closed interconnection of the metal pattern between each antenna segment later. Even if the closed interconnection can be achieved, it will have a huge negative impact on the stealth performance of the antenna; therefore, a low-profile and easy-to-fold microstrip antenna array is used to achieve conformity with the skin antenna. By setting antenna unit installation interfaces distributed according to certain rules on the array panel, the antenna units can be arranged regularly, thereby realizing the function of the antenna. This antenna skin segmented integrated assembly process method designs a segmented skin antenna structure that is first assembled on the left and right, and then assembles N segments of skin antennas into one body, which innovates a segmented assembly process method and also innovates the skin antenna positioning tooling, thereby meeting the manufacturing needs of skin antennas, especially the manufacturing needs of skin antennas with balun structures. It can realize high-gain wide-angle scanning of smart skin antennas and solve the defect of excessive array gain loss at large scanning angles in classic phased array antennas. In broadband distributed array beam synthesis, a sub-array beam synthesis method based on digital delay can also be used to solve the distributed beam synthesis and alignment of smart skin antennas.

[0037] The present invention uses the configuration transformation characteristics of smooth rolling paper cutting technology (kirigami) to expand the complex curved circuit to a plane through dimensionality reduction mapping, and then prints a conformal array structure of a dot matrix with no less than two radiation units arranged regularly or randomly or periodically on a non-metallic material skin carrier substrate or an aluminum alloy metal material. The configuration transformation characteristics of the Kirigami technology are used to expand the complex curved circuit to a plane through dimensionality reduction mapping to achieve complete conformal bonding, and transform the original complex curved surface processing problem into a mature planar circuit preparation process, ensuring that there is sufficient strong interface adhesion and that the patch does not break during deformation. Even under complex wind conditions, the skin can still be stably conformal to the curved surface and ensure the stable operation of the sensor system. The high-precision functional circuit prepared on the plane uses the Kirigami shear structure to achieve conformal coating of the regularly arranged antenna units by setting antenna unit installation interfaces distributed according to certain rules on the array panel, and finally completes the automatic assembly and connection of the circuit on the curved surface through the healing process of the self-healing conductive material. The skin structure with functions of identification, analysis, judgment, and reaction is composed of structures and units that complete the two major functions of sensing or action by coupling with physical quantities such as electricity, magnetism, heat, light, sound, rheology, and mechanical motion, and sensing the changes of these quantities. It not only has the functions of traditional skin in bearing loads, maintaining the aerodynamic shape of the aircraft, and protecting internal devices, but also has the functions of enhancing stealth, reducing vibration and noise, sensing the environment, and sending and receiving information.

[0038] According to the functional composition mode of the smart skin antenna, the present invention divides the designed antenna curved skin into N sections of packaging functional layer, radio frequency functional layer, control and signal processing functional layer with N≥2. The packaging functional layer can realize three major functions: one is the structural bearing function, which can meet the special requirements of the smart skin antenna in terms of structural strength, aerodynamics, etc., and can prevent oxidation, attenuate ultraviolet rays, prevent rain and snow erosion, and resist aerodynamic loads; the second is the system heat dissipation function, which can ensure the normal operation of the power amplifier chip; the third is the electromagnetic protection function, which includes both protection against external electromagnetic attacks and protection against electromagnetic interference inside the system. The radio frequency functional layer can realize the reconfigurable electromagnetic signal radiation / scattering characteristics. After each section of the antenna is divided, the antenna skin is divided into two from the horizontal center line position of the curved arc top, divided into a left skin carrier 1, a right skin carrier 2, and two sections: the purpose of this is to be able to use 3D printing technology to complete the processing and manufacturing of the balun structure 5 and the circular metal pattern 3 and the radiation metal pattern 4 of the inner groove of the antenna. Since 3D printing technology is highly flexible and plastic, it can print different types of antenna accessories according to the different shapes and functional requirements of the antenna. At the same time, 3D printing technology can accurately control the quality and size of the print to ensure the accuracy and precision of the antenna. Moreover, 3D printing technology can efficiently complete the manufacture of antenna components within a certain period of time, greatly improve manufacturing efficiency, enhance the performance of smart skin antennas, and overcome the defects of traditional antenna manufacturing technology that requires multiple steps to manufacture, and has high time and investment costs.

[0039] The present invention adopts a 3D printing or mechanical processing method to process N left and right antenna skins and balun structures, and uses the balun structure to connect at least three rows of radiating metal patterns in the vertical and horizontal directions of the air back cavity radio frequency functional layer under the left and right skins to form a tortoise-back feeding point grid-shaped antenna feeding network radiation unit, thereby realizing a broadband feeding network and curved circuit plane manufacturing and skin curved surface conformal assembly that achieves good impedance matching and amplitude phase distribution in a wider frequency band. The antenna feed network radiating unit can form multiple transmit and receive beams. Compared with the traditional antenna using a passive feed network, it has the following main advantages: (1) The formation and scanning of the transmit beam can be done in a fully digital manner, and the beam scanning speed is faster; (2) The amplitude and phase are continuously adjustable and the control is very precise, making it easy to achieve ultra-low sidelobe beams and form adaptive beam control, such as adaptive zero point to reduce the impact of interference signals on the system; (3) It is easy to calibrate the array unit pattern. DBF can quickly and accurately calibrate the impact of mutual coupling and channel differences, thereby improving the quality of the pattern; (4) Multi-beam control: DBF can form multiple simultaneous low-sidelobe dense beams by digitally processing the received signal. In theory, it can generate an infinite number of arbitrary dense beams, and each beam can fully adapt to the electronic environment of the instant, thereby providing simultaneous detection and tracking capabilities, which is particularly suitable for tracking and detection of multiple positions in smart antennas. (5) The broadband channel can be divided into several narrowband sub-bands, and the optimal amplitude and phase weights can be assigned to each channel in different sub-bands, so as to achieve the optimization of the directional pattern beam in each sub-band and eliminate the adverse effects of frequency dispersion on the directional pattern, which is difficult to achieve in a passive feeding network. (6) The required radiation / scattering characteristics can be generated according to the external electromagnetic environment, so that the radiating unit can have the ability to reconfigure the electromagnetic characteristics, complete the electromagnetic dynamic control of the RF functional layer, and have the ability to agilely change the beam pointing and beam shape. The antenna is based on a cavity-backed microstrip slot antenna, and realizes coupled feeding and impedance matching through a gradient microstrip line. The low-profile design is achieved by reducing the depth of the air cavity and adding a microstrip parallel open-circuit branch at the connection position between the antenna feeding network and the antenna array. The antenna resonant frequency can be adjusted by adjusting the length of the branch. Different from the traditional antenna design method, the beam adaptation of the smart skin antenna is realized by using reconfigurable technology at the RF functional layer and signal processing methods at the back end, which solves the limitation that traditional antennas only rely on signal processing to achieve antenna beam adaptation. The antenna's adaptability can not only be achieved by relying on the control and signal processing units at the back end of the device, but also by realizing the reconfiguration of the radiation / scattering characteristics at the RF functional layer, that is, adding one-dimensional freedom at the RF functional layer. Unlike traditional antennas, it can not only achieve a high degree of integration between the device and the antenna structure packaging functional layer, but also achieve dynamic control of the electromagnetic characteristics of the RF functional layer, breaking through the phased array antenna's reliance on the back end control and signal processing units to achieve antenna beam adaptation.

[0040] At the end of the present invention, after the positioning and assembly of N segmented antenna skins are completed in sequence, the positioning tooling is used to complete the foaming agent fixation of the N segmented antenna skins, and the N segmented antenna skins are assembled into a complete skin antenna of a reconfigurable RF front-end component, breaking the limitation of the traditional antenna opening installation on the aircraft skin, forming a new type of antenna that can be highly integrated with the airborne platform structure and directly bear the environmental load. The positioning tooling completes the foaming agent fixation of the N segmented antenna skins, mainly solving the assembly process problem of the skin antenna of avionics information equipment, so that the assembled skin antenna can meet the requirements of assembly accuracy and the like. The simulation results show that the skin antenna achieves a standing wave resonant frequency shift of more than ±20 MHz, and the bandwidth of the standing wave less than 2 during the frequency shift process is greater than 20 MHz. The self-healing hydrogel has high mechanical deformation capacity (strain up to 200%), low stiffness, recyclability and biocompatibility, and can also use spontaneous intermolecular forces to recover from physical damage caused by extreme strain, pressure or tearing. Based on organic gel composites, it has high conductivity (7×104S m−1), low stiffness (Young's modulus ~20 kPa), high stretchability (strain limit >400%) and mechanical and electrical self-healing properties.

[0041] The present invention can not only realize the integrated manufacturing of the metal pattern of the skin antenna and the balun structure, but also realize the integrated assembly with the reconfigurable RF front-end component through the feed point in the balun structure, which can reduce the difficulty and process requirements of the skin antenna manufacturing process, and even combine the various antennas on it with the wing and fuselage skin, which can effectively eliminate the external exposed antennas on the aircraft, and also greatly reduce the RCS area. It can also effectively utilize the surface area of ​​the aircraft, reduce weight, and reduce the aerodynamic drag of the aircraft. While meeting the manufacturing precision requirements, it can also solve the antenna stealth requirements and realize the intelligent beam adaptation of the skin antenna. The present invention is particularly suitable for a new generation of skin antennas and can significantly improve the functional performance of aircraft, especially the stealth performance.

[0042] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A process for assembling a segmented integrated skin stealth antenna, characterized in that: The following steps are involved: Step 1: Use simulation software to design the required curved skin antenna; Achieving conformality between the microstrip antenna array and the skin antenna; the curved skin antenna has an array-arranged protruding balun structure (5) on the inner concave surface of the curved surface, and an array-arranged radiating metal pattern (4) connected by the balun structure (5) as a bridge, and an array-arranged metal pattern on the outer convex surface of the curved surface; Step 2: According to the curved skin antenna designed in step 1, a skin carrier with the same curvature is obtained, and the skin carrier is divided into N sections, where N ≥ 2; Step 3: Divide each segmented skin carrier into a left skin carrier and a right skin carrier from the transverse centerline position of the curved arc top; Then, 3D printing or mechanical processing is used to process N left and right sections of skin carriers, and an array-arranged balun structure (5) and a radiation metal pattern (4) are manufactured on the inner surface of the skin carrier, and a metal pattern is prepared on the outer surface to obtain a skin carrier with an antenna curved circuit attached to the surface; Step 4: Using the designed curved skin antenna positioning tool (6), place the left and right skin carriers of the same section in the positioning tool (6), use the positioning tool to align and install the left and right skin carriers according to the metal pattern, and after the positioning and installation are completed, use the foaming agent to fill the curved surface grooves of the assembled left and right skin carriers. After the foaming agent is foamed and cured, the positioning tool and the self-healing conductive material are used to perform a healing process, thereby completing the automatic assembly and connection of the circuit on the curved surface of the skin; Step 5: After completing the positioning and assembly of the N segmented left and right skin carriers in sequence, the positioning tool (6) and the foaming agent are used to complete the foaming and fixing of the N segmented antennas, assemble the N segmented antennas into a complete skin antenna, and finally realize the integrated integration of the skin antenna.

2. According to claim 1, a process method for assembling a segmented integrated skin stealth antenna is characterized in that: When the skin carrier is segmented in step 2, it is necessary to avoid dividing the surface metal pattern into two.

3. The process method for assembling a segmented integrated skin stealth antenna according to claim 2 is characterized in that: The radiating metal pattern (4) is regularly arranged along the longitudinal and transverse directions on the inner concave surface; and the metal pattern is a circular metal pattern (3).

4. The process method for assembling a segmented integrated skin stealth antenna according to claim 3 is characterized in that: Radiant metal patterns with multiple interpenetrating network structures (4) are prepared by using paper cutting technology with the help of tools.

5. The process method for assembling a segmented integrated skin stealth antenna according to claim 4 is characterized in that: The skin carrier substrate is specifically polyetheretherketone, polyimide, polymethacrylimide or aluminum alloy.

6. The process method for assembling a segmented integrated skin stealth antenna according to claim 5 is characterized in that: A low-profile back cavity of a conformal skin antenna is designed based on HFSS software. The feeding and impedance matching are carried out through a coaxially connected gradient microstrip line. The microstrip line coupling gap radiates energy, and then a parallel branch is added at the antenna feeding position as a standing wave debugging. An open-circuit microstrip branch is introduced into the feeding network. By changing the branch length, the antenna frequency can be adjusted without changing other parameters of the antenna. The antenna is combined with the skin to achieve conformal installation of the antenna.

7. The process method for assembling a segmented integrated skin stealth antenna according to claim 6 is characterized in that: The balun structure (5) includes a balun, which is a balanced-unbalanced converter. The insulated copper wire on the coaxial cable or the non-magnetic core is neatly wound on a cylindrical frame magnetic material and fixed thereon to form a balun with a frequency range of 3.5-7Mhz. Through two sets of mutually isolated coils, the matched input is converted into a differential output in dB units, thereby realizing the conversion from balanced to unbalanced.

8. The process method for assembling a segmented integrated skin stealth antenna according to claim 7 is characterized in that: The balun structure (5) is a bridge connecting at least three rows of radiating metal patterns (4) to form a radiating unit of an antenna feeding network in the shape of a turtle-back feed point grid.

9. The process for assembling a segmented integrated skin stealth antenna according to claim 7 is characterized in that: The process of automatic assembly and connection of the circuit on the skin surface is specifically as follows: Check the alignment of the circular metal patterns (3) on the surfaces of the left and right skin carriers. If the alignment is accurate, apply conductive glue at the butt joint of the circular metal patterns (3) and the radiating metal patterns (4) on the left and right skin carriers using electrical installation technology to complete the closed interconnection of the circular metal patterns (3) and the radiating metal patterns (4); If the alignment is inaccurate, use a scalpel to clean the foaming agent, then use the foaming agent repeatedly to foam, and re-position and assemble until the alignment is accurate. Then use conductive glue to close and interconnect the butt joints of the circular metal pattern (3) and the radiation metal pattern (4) of the left and right skin carriers.

10. The process method for assembling a segmented integrated skin stealth antenna according to claim 9 is characterized in that: The conductive adhesive is specifically conductive silver paste or a self-healing conductive material based on conductive nano Ag powder and polycaprolactone polymer.

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