Low-altitude anti-interference unmanned aerial vehicle antenna cabin double-sided FSS quick-release film covering assembly and positioning frame

Abstract

The invention provides a low-altitude anti-interference unmanned aerial vehicle antenna cabin double-sided FSS quick release film covering assembly and a positioning frame, the film covering assembly comprises a dielectric substrate, a first FSS metal pattern layer and a second FSS metal pattern layer, the first FSS metal pattern layer and the second FSS metal pattern layer are arranged on the front face and the back face of the dielectric substrate respectively, and the outer side of the dielectric substrate is covered with a protective film layer; an overturning hinge mechanism is arranged on the edge of one side of the film covering assembly, and a spring self-locking quick-release buckle is arranged on the edge of the opposite side; the positioning frame is of a rectangular frame body structure, a three-point reference positioning system composed of two cylindrical positioning pins and a rhombic positioning pin which are asymmetrically distributed is arranged on the inner side of the frame body, and two round positioning holes and a rhombic positioning hole which are matched with each other are formed in the corresponding positions of the film covering assembly. Different faces are selected to face outwards by turning over the film covering assembly, switching between two frequency selection characteristics can be achieved, tool-free quick disassembly and assembly are achieved in cooperation with a quick disassembly buckle, and the installation precision and correctness are ensured through three-point reference and a mistakenly-assembly-preventing key groove.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) technology, specifically to a double-sided FSS quick-release film assembly and positioning frame for a low-altitude anti-jamming UAV antenna compartment. Background Technology

[0002] With the rapid development of the low-altitude economy, multi-rotor drones have been widely used in logistics delivery, agricultural plant protection, power line inspection, emergency rescue, and urban air traffic. In the low-altitude flight environment, drones face increasingly complex electromagnetic interference threats, including ground communication base stations, radar systems, industrial radio frequency equipment, and deliberate electromagnetic attacks. As the core component housing navigation antennas, data link antennas, and remote control antennas, the anti-interference performance of the drone directly determines its flight safety and mission reliability.

[0003] Frequency Selective Surfaces (FSS), as a type of space electromagnetic filtering device, consist of periodically arranged metal patches or slotted units that can selectively transmit or reflect electromagnetic waves in specific frequency bands. Applying FSS technology to UAV antenna radomes can effectively block out-of-band interference signals while ensuring normal transmission of communication signals, making it an important technical approach to improve the low-altitude anti-jamming capabilities of UAVs.

[0004] Drones need to operate on different frequency band combinations in different mission scenarios. Traditional single-sided FSSs can only provide fixed frequency selection characteristics, which cannot meet the frequency band switching requirements of multi-mission scenarios. In addition, the field operation conditions of drones are limited, and antenna compartment maintenance and FSS cover replacement usually require specialized tools and operating experience. Existing FSS covers mostly use bolt fixing, which is cumbersome, time-consuming, and carries the risk of incorrect installation (such as installing it backwards or rotating it at the wrong angle). Incorrect installation will seriously affect the antenna's transmission and reception performance and may even lead to flight accidents. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a double-sided FSS quick-release coating assembly and positioning frame for low-altitude anti-jamming UAV antenna compartments, thereby solving the problems mentioned in the background art. The present invention allows switching between two frequency selection characteristics by flipping the coating assembly to select different outward faces. Combined with quick-release buckles, tool-free assembly and disassembly can be completed within 15 seconds. Three-point reference and anti-misassembly keyway ensure installation accuracy and correctness.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: a double-sided FSS quick-release coating assembly for a low-altitude anti-interference UAV antenna compartment, comprising a double-sided FSS coating assembly, wherein the double-sided FSS coating assembly includes a dielectric substrate, a first FSS metal pattern layer, a second FSS metal pattern layer, front and back protective coating layers, and an edge sealing strip, wherein the first FSS metal pattern layer is side A and adopts a cross-slot array type, and the second FSS metal pattern layer is side B and adopts a ring-shaped slot array type.

[0007] Furthermore, it also includes a flip-up hinge mechanism, a spring-loaded self-locking quick-release buckle assembly, and an antenna compartment mounting interface board; The reversible hinge mechanism includes a hinge shaft, a hinge seat, a limit stop, and a torsion spring, wherein the torsion spring is used to provide flipping assistance and end-point holding force; The spring self-locking quick-release buckle assembly includes two sets of spring buckles, one on the left and one on the right. Each set includes a buckle head, a spring, a guide rod, and a release button. The antenna compartment mounting interface board includes an interface board body, a positioning frame mounting screw hole, and a cable through-cabin sealing joint.

[0008] Furthermore, the dielectric substrate is made of Rogers RO4003C low-loss high-frequency material, and the planar dimensions of the dielectric substrate are customized according to the antenna compartment opening dimensions.

[0009] Furthermore, the first FSS metal pattern layer adopts a cross-slot array type unit, which is formed by etching on a thick copper foil, and forms a bandpass window with a 3dB bandwidth of about 200MHz centered at 1.575GHz.

[0010] Furthermore, the second FSS metal pattern layer employs an annular slot array type unit, which is formed by etching on copper foil and forms a bandpass window centered at 2.44 GHz with a 3 dB bandwidth of approximately 300 MHz.

[0011] Furthermore, the protective coating layer is made of PET film and is adhered to the outer surface of the FSS pattern layer with optical-grade transparent adhesive.

[0012] Furthermore, the flip hinge mechanism is located on the long side of the coating assembly. The flip hinge mechanism includes a hinge shaft made of 304 stainless steel. The hinge shaft is fixed to the edge of the positioning frame by hinge seats at both ends. The flip hinge mechanism has a built-in micro torsion spring, which provides holding torque when the coating assembly is flipped to the 0° or 180° position. Limiting blocks are provided at both ends of the hinge, which are used to precisely limit the flip angle within the range of 0° to 180°.

[0013] Furthermore, the spring-loaded quick-release buckle is located on the long side of the film-coated assembly opposite to the hinge. The spring-loaded quick-release buckles are distributed in two sets in a symmetrical manner. Each set of spring-loaded quick-release buckles includes: a stainless steel buckle head, a compression spring, a guide rod, and a release button.

[0014] A three-point reference anti-misalignment positioning frame for use with the above-mentioned coating assembly includes a three-point reference positioning frame, which includes a rectangular frame, a first cylindrical positioning pin, a second cylindrical positioning pin, a rhomboid positioning pin, a positioning pin seat, an anti-misalignment key strip, and an anti-misalignment keyway. A trapezoidal convex key is provided on the inner side of one short side of the positioning frame, and the coating assembly is provided with a matching trapezoidal groove on the corresponding short side. Both the convex key and the groove are asymmetrically arranged.

[0015] Furthermore, the first cylindrical positioning pin is located in the upper left corner of the positioning frame to restrict the degrees of freedom in the X and Y directions; the second cylindrical positioning pin is located in the lower left corner of the positioning frame and cooperates with the first cylindrical pin to restrict the rotational degree of freedom around the Z axis; the rhomboid positioning pin is located in the middle right side of the positioning frame, restricting only one degree of freedom and providing a thermal expansion compensation gap; two circular positioning holes and one rhomboid positioning hole are correspondingly provided on the coating assembly.

[0016] The beneficial effects of this invention are: This invention features FSS patterns with different resonant frequencies on both sides of a single dielectric substrate. Combined with a flip-up hinge mechanism, operators can switch between two frequency selection characteristics simply by mechanically flipping the substrate. Compared to electrically controlled active FSS solutions, this eliminates the need for active components, bias circuits, and control systems, achieving zero-power, highly reliable frequency switching.

[0017] This invention utilizes a spring-loaded self-locking quick-release buckle design, allowing the film-coated components to be installed and removed without any tools. A single person can complete the flipping and relocking within 15 seconds, which is more than 20 times more efficient than the traditional bolt fixing method. It is particularly suitable for the emergency deployment needs of drones in the field.

[0018] This invention uses a three-point reference (two circles and one rhombus) positioning system to ensure installation repeatability better than ±0.05mm, guaranteeing precise consistency between the relative positions of the FSS pattern and the antenna. The asymmetric anti-misassembly keyway structure physically eliminates the possibility of incorrect installation from the front or back, or incorrect rotation angle, achieving the safety goal that even first-time operators cannot make a mistake.

[0019] The total weight of the coating components used in this invention is no more than 28g, the weight of the positioning frame is about 35g, and the overall solution adds only about 63g of weight, which has a negligible impact on the endurance of the multi-rotor drone.

[0020] In this invention, the FSS pattern is manufactured using standard PCB etching technology, the positioning frame is made of CNC machined aluminum alloy, and the buckles and hinges are all standardized mechanical parts. This results in low overall production costs and facilitates mass production and widespread application. Within the corresponding passband frequency band, the signal insertion loss is less than 0.8dB, and the out-of-band interference suppression reaches over 20dB, significantly improving the communication and navigation reliability of UAVs in complex low-altitude electromagnetic environments. Attached Figure Description

[0021] Figure 1 This is a diagram illustrating the overall architecture of the multi-rotor UAV antenna bay system in an embodiment of the present invention. Figure 2 This is a schematic diagram of the stacked structure and unit pattern of the double-sided FSS coated component in an embodiment of the present invention; Figure 3 This is a side view of the reversible hinge mechanism and a schematic diagram of two working states in an embodiment of the present invention; Figure 4 This is an exploded view of the quick-release film-coated assembly in an embodiment of the present invention; Figure 5 This is a planar structural diagram of the three-point reference positioning frame in an embodiment of the present invention; Figure 6 This is a detailed schematic diagram of the anti-misinstallation limiting mechanism in an embodiment of the present invention; Figure 7 This is a flowchart illustrating the disassembly, assembly, and frequency band switching operations of the FSS coating component in an embodiment of the present invention. Figure 8 This is a schematic diagram illustrating the dual-mode signal filtering principle of the dual-sided FSS in an embodiment of the present invention; Figure 9 This is a simulation diagram comparing the electric field transmission distribution of the double-sided FSS and the single-sided FSS in Experiment 1 of this invention. Figure 10 This is a comparison diagram of the installation positioning accuracy scattering in Experiment 2 of this invention. Figure 11 This is a comparative chart showing the operational efficiency and reliability of error prevention in Experiment 3 of this invention. Figure 12 This is a comprehensive evaluation diagram of the anti-interference effect under multiple interference scenarios in Experiment 4 of this invention. Detailed Implementation

[0022] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0023] Please see Figures 1 to 12 The present invention provides the following technical solution: a double-sided FSS quick-release film assembly and positioning frame for a low-altitude anti-jamming UAV antenna compartment, which consists of the following components: (1) Double-sided FSS coating assembly: including a dielectric substrate, a first FSS metal pattern layer (A side, cross-shaped slit array type), a second FSS metal pattern layer (B side, annular slit array type), front and back protective coating layers, and edge sealing strips.

[0024] (2) Reversible hinge mechanism: including hinge shaft, hinge seat, limit stop, and torsion spring (providing flipping assistance and end point holding force).

[0025] (3) Spring self-locking quick release buckle assembly: includes two sets of spring buckles on the left and right, each set including buckle head, spring, guide rod and release button.

[0026] (4) Three-point reference limit positioning frame: including rectangular frame, first cylindrical positioning pin, second cylindrical positioning pin, rhomboid positioning pin, positioning pin seat, anti-misalignment key strip and keyway.

[0027] (5) Antenna compartment mounting interface board: including the interface board body, positioning frame mounting screw holes, and cable through-bag sealing joint.

[0028] From top to bottom, the layers are: protective coating layer → first FSS metal pattern layer → dielectric substrate → second FSS metal pattern layer → protective coating layer, forming a complete double-sided FSS coated assembly. This assembly is connected to a three-point reference positioning frame via a flip hinge mechanism, and the positioning frame is fixed to the mounting interface plate of the UAV antenna compartment with bolts.

[0029] The dielectric substrate is made of Rogers RO4003C low-loss high-frequency material with a dielectric constant εr=3.55, a loss tangent tanδ=0.0027, and a thickness of 1.524mm, balancing electrical performance and mechanical strength. The substrate planar dimensions are customized according to the antenna compartment opening size, with a typical size of 120mm×80mm.

[0030] The first FSS metal pattern layer (A-side) uses a cross-slot array of cells, etched onto a 35μm thick copper foil. The cell period Pa = 18mm, the cross arm length La = 16.2mm, the arm width Wa = 1.8mm, and the resonant frequency is designed to be 1.575GHz (GPSL1 band), forming a bandpass window centered at 1.575GHz with a 3dB bandwidth of approximately 200MHz.

[0031] The second FSS metal pattern layer (B-side) uses a ring-shaped slot array of cells, also etched on a 35μm copper foil. The cell period is Pb=12mm, the ring outer diameter is Rb=5.2mm, the ring slot width is Wb=0.8mm, the resonant frequency is designed to be 2.44GHz (WiFi / data link band), and a bandpass window with a 3dB bandwidth of approximately 300MHz is formed with 2.44GHz as the center.

[0032] The protective coating layer is made of 50μm thick PET (polyethylene terephthalate) film, which is attached to the outer surface of the FSS pattern layer with optical grade transparent adhesive. It plays a role in moisture protection, dust protection and scratch protection. Its dielectric constant εr=3.0, and its influence on the FSS resonant frequency has been compensated in the design stage.

[0033] The flip hinge mechanism is located on the long side of the coating assembly. The hinge shaft is made of 304 stainless steel, with a diameter of 3mm, and is fixed to the edge of the positioning frame via hinge seats at both ends. The hinge incorporates a miniature torsion spring, providing a stable holding torque (approximately 0.15 N·m) when the coating assembly is flipped to the 0° (A side facing out) or 180° (B side facing out) position, preventing spontaneous flipping due to vibration. Limit stops are located at both ends of the hinge to precisely limit the flipping angle within the range of 0° to 180°.

[0034] The spring-loaded self-locking quick-release clips are located on the long side of the laminating assembly opposite the hinge, with two sets symmetrically distributed on the left and right. Each set of clips includes: a stainless steel clip head (hook-shaped, 8mm wide), a compression spring (15N spring force, 3mm stroke), a guide rod, and a release button. During installation, after flipping the laminating assembly into place, press the edge of the assembly; the clip head will automatically engage with the protrusion on the edge of the positioning frame under the spring force, producing a "click" sound to indicate that it is locked in place. During disassembly, press the release buttons on both sides simultaneously; the clip head will retract and release the laminating assembly.

[0035] The three-point datum positioning system employs the classic "two circles and one rhombus" three-point positioning principle. Three positioning pins are set on the inner side of the positioning frame: the first cylindrical positioning pin (diameter φ4mm, tolerance h6) is located in the upper left corner of the positioning frame, restricting the X and Y degrees of freedom; the second cylindrical positioning pin (diameter φ4mm, tolerance h6) is located in the lower left corner of the positioning frame, cooperating with the first cylindrical pin to restrict the rotational degree of freedom around the Z-axis; the rhombus positioning pin (rhombus cross-section, diagonal dimensions 4mm × 6mm) is located in the middle right side of the positioning frame, restricting only one degree of freedom and providing thermal expansion compensation clearance. Correspondingly, the coating assembly has two circular positioning holes (diameter φ4.01mm, tolerance H7) and one rhombus positioning hole (with a 0.02mm clearance along the major axis and a 0.5mm clearance along the minor axis). The three-point positioning system ensures that the coating assembly installation repeatability is better than ±0.05mm.

[0036] Anti-misassembly keyway structure: A trapezoidal convex key (6mm wide, 3mm high) is set on the inner side of one short side of the positioning frame, and a matching trapezoidal groove is set on the corresponding short side of the coating assembly. Since both the convex key and the groove are asymmetrically arranged (offset at one end of the short side rather than in the center), the coating assembly can only be inserted into the positioning frame with one correct orientation and position, completely eliminating the possibility of 180° rotation misassembly and reverse flipping misassembly from a physical structure perspective.

[0037] This embodiment also provides a description of the accompanying drawings: like Figure 1 As shown, the double-sided FSS coating assembly and the three-point reference positioning frame are installed in the antenna compartment position in the center of the multi-rotor UAV fuselage. The antenna compartment is located in the central area of ​​the upper surface of the main fuselage, and its upper opening is covered by the FSS coating assembly. The positioning frame is fixed to the frame of the antenna compartment shell, and the FSS coating assembly is detachably connected to the positioning frame via positioning pins and quick-release buckles.

[0038] Figure 2 The diagram showcases the stacked cross-sectional structure of the double-sided FSS coated module and the FSS unit pattern design on both sides. The cross-sectional view on the left clearly shows the stacking relationship and thickness distribution of the five-layer structure, while the right side displays the planar patterns of the cross-slot type FSS unit on side A and the annular slot type FSS unit on side B. The double-sided FSS design generates resonance at different frequencies, achieving selective transmission to different operating frequency bands.

[0039] Figure 3 The side view of the flip-up hinge mechanism and its two flip states are shown. The left side represents state one (A side facing outwards), suitable for filtering the GPS L1 navigation frequency band; the right side represents state two (B side facing outwards), suitable for filtering the 2.4GHz data link frequency band. Operators can quickly switch between the two filtering modes by simply releasing the quick-release clips, flipping the coated assembly 180°, and relocking the clips, with the entire process taking no more than 15 seconds.

[0040] Figure 4 The assembly hierarchy of all components of this invention is shown in an exploded view. From top to bottom, they are: top protective cover, double-sided FSS coating assembly, flip hinge mechanism, left and right spring quick-release buckles, three-point reference positioning frame, antenna compartment mounting interface plate, and antenna compartment shell. The assembly direction and connection relationship between each component are clearly defined, making it easy for operators to understand the assembly sequence.

[0041] Figure 5 A top view of the three-point reference positioning frame is shown. The inner side of the positioning frame has three asymmetrically distributed positioning pins: a first cylindrical positioning pin P1 at the upper left corner, a second cylindrical positioning pin P2 at the lower left corner, and a diamond-shaped positioning pin P3 in the middle of the right side. P1 and P2 restrict three degrees of freedom: translation in the X and Y directions and rotation along the Z axis. P3 restricts only one degree of freedom and retains a thermal expansion compensation gap along the major axis. An asymmetrically arranged trapezoidal key is located on the upper right edge of the positioning frame to prevent incorrect installation.

[0042] Figure 6The working principle of the anti-misinstallation limiting mechanism is clearly demonstrated by comparing the left and right sides. The left side shows the correct installation direction, where the trapezoidal convex key precisely matches the trapezoidal groove on the laminating component, and the three positioning pins are simultaneously aligned with their corresponding positioning holes, allowing the component to be inserted smoothly. The right side shows the incorrect installation direction after rotating 180°. In this case, the convex key position physically interferes with the edge of the laminating component, preventing it from being inserted into the positioning frame, thus structurally eliminating the possibility of misinstallation.

[0043] Figure 7 The complete frequency band switching operation process of the FSS coated module is illustrated in flowchart form. The operator first confirms the target operating frequency band and determines whether the coated module needs to be flipped. If flipping is required, five steps are executed sequentially: releasing the latch, flipping 180°, aligning with the three-point positioning reference, pressing to lock, and performing a function check. The entire process is tool-free and can be completed by a single person, with a total time not exceeding 15 seconds. If the current configuration is correct, the process proceeds directly to the function check stage.

[0044] Figure 8 Two operating modes of the double-sided FSS coated module are described. In Mode A, side A (cross-slit type) faces the external electromagnetic environment. After the broadband incident signal is filtered by the FSS, only the 1.575 GHz GPSL1 navigation signal is transmitted to the antenna inside the antenna compartment, while other out-of-band interference signals are reflected by the FSS. In Mode B, by flipping the module so that side B (ring-shaped slit type) faces outward, selective transmission of the 2.44 GHz data link communication frequency band is achieved. The switching between the two modes is achieved entirely through mechanical flipping, requiring no active components or additional power consumption.

[0045] Specifically, the working principle of this invention is as follows: This invention leverages the organic combination of the spatial filtering characteristics of a frequency-selective surface (FSS) and a mechanical flip-to-switch mechanism. When electromagnetic waves irradiate the surface of the FSS-coated assembly, the resonant units on the FSS metal pattern layer resonate at a specific frequency, forming a low-impedance path near that frequency, allowing electromagnetic waves of that frequency band to be transmitted. At non-resonant frequencies, the FSS exhibits high impedance characteristics, reflecting the electromagnetic waves back. Because the dielectric substrate of this invention has FSS patterns with different resonant frequencies designed on both sides, when side A faces the external environment, the incident wave first passes through the frequency selection of the FSS on side A, allowing only the passband signal designed on side A to penetrate. When the coated assembly is flipped so that side B faces outward, the frequency selection characteristics of the FSS on side B are switched. The two FSS sides are isolated by the dielectric substrate, the substrate thickness of which is much smaller than the operating wavelength. The coupling effect between the two sides can be compensated through design, ensuring that the filtering performance of each side is not significantly affected when working independently.

[0046] This embodiment also provides the following algorithm formula: Formula 1: Formula for calculating the resonant frequency of an FSS unit: The resonant frequency of an FSS cell is determined by its geometry and the dielectric parameters of the substrate. For a cross-slot type FSS cell (A-side), the resonant frequency can be calculated using the following formula:

[0047] The present invention uses 16.2 mm; eff —The effective dielectric constant of the substrate is determined by the following formula.

[0048] Formula 2: Formula for calculating the effective dielectric constant of a substrate: When the FSS metal pattern is located on one side of the dielectric substrate (the other side is air), the effective dielectric constant needs to take into account the combined effect of the substrate and the air:

[0049] Formula 3: Formula for the resonant frequency of annular slot type FSS (B-plane): For the B-side annular slot type FSS element, its resonant frequency is related to the average perimeter of the ring:

[0050] Formula 4: FSS transmission coefficient calculation formula: Near the resonant frequency, the transmission coefficient of the FSS can be expressed by an equivalent circuit model as follows:

[0051] At the resonant frequency FSS → 0, therefore → 1, achieving complete transmission.

[0052] Formula 5: Correction formula for the coupling effect of two-sided FSS: When the coated assembly operates with one side facing outwards, the FSS pattern layer on the back side is weakly coupled to the front side through the dielectric substrate. The correction amount for the actual resonant frequency is:

[0053] because g However, the exponential decay term still makes Δ The offset has been pre-compensated in the design and is kept within a controllable range.

[0054] Formula 6: Formula for calculating the repeatability of a three-point positioning system: The installation repeatability of a three-point positioning system is determined by the clearance between the positioning pin and the positioning hole:

[0055] Substitute the parameters to calculate. total < 0.05 mm.

[0056] Formula 7: Evaluation index of anti-interference improvement: The degree to which FSS coating components improve the anti-interference capability of antenna systems is quantified by the following indicators:

[0057] Experimental results show that, at out-of-band interference frequencies, the present invention... imp It can reach over 20dB.

[0058] This embodiment also provides the following alternatives: Alternative Solution 1: Rotary Replacement of Flip-Type Switching Mechanism. The hinge flip-type mechanism is replaced with a central rotating mechanism. The coating assembly is designed as a circle, supported at the center of the positioning frame by a central bearing. The upper and lower halves of the coating assembly are respectively equipped with FSS patterns on side A and side B. The operator can switch the different FSS pattern areas to the antenna radiation window coverage position by rotating the coating assembly 180°. The advantage of this solution is that the rotation operation is more intuitive; the disadvantage is that the circular coating assembly has lower area utilization, and the central bearing increases structural complexity and weight. The three-point positioning and anti-misassembly principles remain unchanged; only the positioning pins and keyways need to be adjusted to arc-shaped guide rails and angle limiting structures adapted to rotational movement.

[0059] Alternative Solution 2: A sliding rail pull-out mechanism replaces the flip-over switching mechanism. One A-side coating component and one B-side coating component are fabricated, and the two components are stacked and installed in the double-layered sliding rails of the positioning frame. When switching is needed, the component on the current working surface is pulled out along the sliding rail, exposing the other component underneath. The advantage of this solution is that each component only performs the function of a single-sided FSS (Fixed Side Steering) module, making design and manufacturing simpler. The disadvantage is that it requires carrying two components, increasing the number of spare parts and storage space, and the double-layered sliding rail structure increases the thickness and weight of the positioning frame. Misalignment prevention can be achieved through different sliding rail widths or asymmetrical guide rail cross-sections.

[0060] Alternative Solution 3: Magnetic Replacement of Spring-Lock Quick-Release Mechanism. The spring-locking clips are replaced with a permanent magnet adsorption mechanism. Neodymium iron boron permanent magnets are embedded at corresponding positions on the edges of the positioning frame and the coating assembly, using magnetic force to achieve adsorption and fixation of the coating assembly. This solution requires no pressing operation; it automatically adsorbs after placement, and can be easily pulled off for removal. The advantages are a simpler structure and more intuitive operation; the disadvantages are that the reliability of the magnet's holding force in the drone's vibration environment needs to be verified, and the magnet may cause electromagnetic interference to sensitive electronic components in the antenna compartment, requiring additional magnetic shielding measures. The three-point positioning reference system and the mis-assembly keyway structure remain unchanged.

[0061] This embodiment also provides experimental verification based on the above technical solution, as detailed below: Experimental Overview: This embodiment designed four sets of comparative experiments to systematically compare and evaluate the present invention's solution with the traditional single-sided FSS bolt fixing solution (control group) from four dimensions: electromagnetic filtering performance, installation positioning accuracy, operational efficiency, and anti-interference effect in multiple scenarios. Each set of experiments was conducted in the same test environment and under the same conditions to ensure the fairness and comparability of the results.

[0062] Experiment 1: Comparison of Electromagnetic Field Transmission Distribution on Two-Sided FSS Electromagnetic field distribution simulations of the double-sided FSS coated module of this invention and a conventional single-sided FSS were performed using full-wave electromagnetic simulation software (CST Microwave Studio). The electric field transmission distribution characteristics of the two schemes were observed under a 1.575 GHz plane wave normal incidence condition.

[0063] Figure 9 The paper presents a comparison of the electric field transmission distribution of the A-side FSS of this invention and a conventional single-sided FSS under normal incidence of a plane wave at 1.575 GHz. The left image shows the scheme of this invention, where the cross-shaped slit region exhibits bright and strong transmission characteristics, and the field distribution is highly matched with the FSS pattern, indicating efficient transmission of in-band signals. The right image shows the conventional scheme, where the transmission field strength is significantly weaker due to the poor impedance matching characteristics of the single-sided structure, and the slit characteristics are blurred, confirming the advantages of this invention in filtering performance.

[0064] Experiment 2: Comparison of Installation Positioning Accuracy Repeatability The three-point reference positioning frame scheme of the present invention and the traditional bolt fixing scheme were subjected to 30 repeated installation and disassembly tests. The offset of the center point of the film-coated component in the X and Y directions after each installation was recorded using a coordinate measuring machine (CMM) to evaluate the positioning repeatability of the two schemes.

[0065] Figure 10The left and right figures show the data from the three-point reference positioning scheme of this invention. The 30 measurement points are highly concentrated at the origin, with standard deviations of only σx = 0.008 mm and σy = 0.009 mm, and all data points are within ±0.05 mm. The right figure shows the data from the traditional bolt fixing scheme, where the measurement point dispersion is significantly increased, with standard deviations of σx = 0.042 mm and σy = 0.038 mm. Approximately 27% of the data points exceed the ±0.05 mm range, fully demonstrating the significant advantage of the three-point reference positioning system in terms of repeatability accuracy.

[0066] Experiment 3: Comparison of disassembly and assembly efficiency and error prevention reliability Twenty operators with varying levels of experience (including 10 novices and 10 skilled technicians) were invited to conduct disassembly and assembly tests on both the present invention and the traditional bolt-fixing method. The time spent on each disassembly and assembly attempt and the number of incorrect attempts were recorded.

[0067] Figure 11 The comparison results of operational efficiency and reliability of error prevention are presented in two parts. The upper table shows that the average disassembly and assembly time for a novice using the present invention is only 12.3 seconds, which is 1 / 39th of the 478 seconds of the traditional bolt solution, improving efficiency by nearly 39 times; at the same time, no tools are required, making the operation threshold extremely low. The lower error prevention test matrix shows that in 500 incorrect installation attempts, including 180° rotation, flipping, 90° rotation, and random insertion at any angle, the error prevention mechanism achieved a 100% interception rate, completely eliminating the possibility of incorrect installation. In contrast, the traditional solution resulted in 17 incorrect installations in 200 installation operations (error rate of 8.5%), posing a significant safety hazard.

[0068] Experiment 4: Comprehensive Evaluation of Anti-interference Effect under Multiple Interference Scenarios. Four typical low-altitude electromagnetic interference scenarios were simulated in a microwave anechoic chamber environment. The signal-to-noise ratio (SNR) was tested on the antenna system with the FSS coating component of this invention and the bare antenna system without FSS. The anti-interference improvement effect of this invention was comprehensively evaluated.

[0069] Figure 12Test data from four typical low-altitude interference scenarios comprehensively demonstrate the anti-interference effect of this invention. The scenarios cover base station co-channel interference (0.9 GHz), radar sidelobe interference (5.8 GHz), industrial ISM band interference (2.45 GHz), and deliberate broadband suppression interference. The signal-to-noise ratio of the antenna system with and without the FSS coating component was tested. The results show that the anti-interference improvement in the four scenarios is 20.3 dB, 23.4 dB, 18.9 dB, and 19.7 dB, respectively, with an average improvement of 20.6 dB. After installing the FSS, the communication availability rate significantly increased from 47.5% to 99.2%, while the in-band signal insertion loss was less than 0.8 dB, verifying the design goal of this invention to significantly enhance anti-interference capability while ensuring communication quality.

[0070] Experiment Summary: Four sets of comparative experiments comprehensively verified the significant advantages of this invention over existing technologies in four dimensions: electromagnetic filtering performance, positioning accuracy, operational efficiency, and actual anti-interference effect. The double-sided FSS design exhibits excellent frequency selectivity and low insertion loss performance in both operating frequency bands; the installation repeatability of the three-point reference positioning system is improved by 5 times; the tool-free quick-release operation efficiency is improved by nearly 39 times; the anti-misinstallation mechanism achieves a 100% interception rate in 500 tests; and the average anti-interference improvement reaches 20.6dB under various interference scenarios.

[0071] The foregoing has shown and described the basic principles and main features of the present invention and its advantages. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention.

[0072] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A low-altitude anti-jamming unmanned aerial vehicle antenna cabin double-sided FSS quick-release film assembly, comprising a double-sided FSS film assembly, characterized in that: The double-sided FSS coating assembly includes a dielectric substrate, a first FSS metal pattern layer, a second FSS metal pattern layer, front and back protective coating layers, and an edge sealing strip. The first FSS metal pattern layer is side A and adopts a cross-shaped slit array, while the second FSS metal pattern layer is side B and adopts a ring-shaped slit array.

2. The low-altitude anti-jamming UAV antenna pod double-sided FSS quick-release film covering assembly according to claim 1, characterized in that: It also includes a flip-up hinge mechanism, a spring-locking quick-release buckle assembly, and an antenna compartment mounting interface board; The reversible hinge mechanism includes a hinge shaft, a hinge seat, a limit stop, and a torsion spring, wherein the torsion spring is used to provide flipping assistance and end-point holding force; The spring self-locking quick-release buckle assembly includes two sets of spring buckles, one on the left and one on the right. Each set includes a buckle head, a spring, a guide rod, and a release button. The antenna compartment mounting interface board includes an interface board body, a positioning frame mounting screw hole, and a cable through-cabin sealing joint.

3. The low-altitude anti-jamming UAV antenna pod double-sided FSS quick-assembly film covering assembly according to claim 1, characterized in that: The dielectric substrate is made of Rogers RO4003C low-loss high-frequency material, and the planar dimensions of the dielectric substrate are customized according to the opening size of the antenna compartment.

4. The low-altitude anti-jamming UAV antenna pod double-sided FSS quick-assembly film covering assembly according to claim 1, characterized in that: The first FSS metal pattern layer uses a cross-slot array of cells, which is formed by etching on a thick copper foil and forms a bandpass window with a 3dB bandwidth of about 200MHz centered at 1.575GHz.

5. The low-altitude anti-jamming UAV antenna pod double-sided FSS quick-assembly film covering component of claim 4, characterized in that: The second FSS metal pattern layer uses an annular slot array type unit, which is formed by etching on copper foil and forms a bandpass window with a 3dB bandwidth of about 300MHz centered at 2.44GHz.

6. The low-altitude anti-jamming UAV antenna pod double-sided FSS quick-assembly film covering assembly of claim 1, wherein: The protective coating layer is made of PET film and is attached to the outer surface of the FSS pattern layer with optical-grade transparent adhesive.

7. The low-altitude anti-jamming UAV antenna pod double-sided FSS quick- detach film cover assembly of claim 2, wherein: The flip hinge mechanism is located on the long side of the coating assembly. The flip hinge mechanism includes a hinge shaft made of 304 stainless steel. The hinge shaft is fixed to the edge of the positioning frame by hinge seats at both ends. The flip hinge mechanism has a built-in micro torsion spring, which provides holding torque when the coating assembly is flipped to the 0° or 180° position. Limiting blocks are provided at both ends of the hinge, which are used to precisely limit the flip angle within the range of 0° to 180°.

8. The low altitude anti-jamming UAV antenna pod double-sided FSS quick- detach film cover assembly of claim 1, wherein: The spring-loaded quick-release buckle is located on the long side of the film-coated assembly opposite to the hinge. The spring-loaded quick-release buckles are distributed in two sets in a symmetrical manner. Each set of spring-loaded quick-release buckles includes: a stainless steel buckle head, a compression spring, a guide rod, and a release button.

9. A positioning frame for use with the coating assembly as described in claim 1, comprising a three-point reference positioning frame, characterized in that: The three-point reference limiting positioning frame includes a rectangular frame, a first cylindrical positioning pin, a second cylindrical positioning pin, a rhomboid positioning pin, a positioning pin seat, an anti-misalignment key strip, and an anti-misalignment keyway. A trapezoidal convex key is provided on the inner side of one short side of the positioning frame, and a matching trapezoidal groove is provided on the corresponding short side of the coating component. Both the convex key and the groove are asymmetrically arranged.

10. The positioning frame according to claim 9, characterized in that: The first cylindrical positioning pin is located in the upper left corner of the positioning frame and is used to restrict the degrees of freedom in the X and Y directions; the second cylindrical positioning pin is located in the lower left corner of the positioning frame and cooperates with the first cylindrical pin to restrict the rotational degree of freedom around the Z axis; the rhomboid positioning pin is located in the middle right side of the positioning frame and restricts only one degree of freedom and provides a thermal expansion compensation gap; two circular positioning holes and one rhomboid positioning hole are correspondingly provided on the coating assembly.

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