Metasurface phased array antenna with wideband high gain and low radar cross section

Abstract

The application discloses an ultrathin phased array antenna with wideband high gain and low radar scattering cross section, which comprises, from bottom to top, a ground plate, a second dielectric substrate layer, an ultrathin surface layer, a first dielectric substrate layer and a radiation patch layer. The ultrathin phased array antenna is characterized in that the low profile antenna structure with the functions of wide-angle stable scanning, wideband high gain radiation and wideband radar scattering cross section reduction is realized by integrating the subwavelength ultrathin surface under the radiation layer.

Description

Technical Field

[0001] This invention belongs to the field of microwave technology and antenna engineering technology, specifically relating to a metasurface phased array antenna with broadband high gain and low radar cross section. Background Technology

[0002] In radar detection, satellite communication, and next-generation mobile communication systems, electronically scanned phased array antennas have become irreplaceable core components due to their rapid beam pointing capability. With the continuous expansion of application scenarios, the system has put forward multiple almost contradictory requirements for antenna performance: it needs to achieve a wide-angle scan of ±60° to cover a wide airspace, while maintaining a low profile and low cost to adapt to large-scale commercial deployment; it requires high gain and stable radiation efficiency in a wide frequency band, while also expecting a low radar cross section to meet stealth requirements.

[0003] However, the physical characteristics of phased array antennas inherently create conflicts between these performance characteristics. With increasing scanning angle, the inter-element coupling effect in traditional planar microstrip arrays intensifies dramatically, leading to scanning dead zones—where energy is severely reflected and cannot be radiated at specific angles. A more fundamental constraint is that the technological paths adopted to achieve wide-angle scanning often force difficult trade-offs between structural complexity, manufacturing cost, and electrical performance; to date, no mature solution has emerged that can simultaneously meet all of these requirements within the framework of standard manufacturing processes.

[0004] Currently, to achieve large-angle scanning targets, the industry mainly follows two distinct technical routes, but both have significant drawbacks: Option 1: Wide-beam array based on large-pitch metasurfaces This scheme is most similar in form to the present invention, also employing a two-layer structure of "radiation layer-metasurface layer". Its design concept is to artificially widen the beamwidth of a single radiation unit by controlling the electromagnetic properties of the lower metasurface, and then arrange these wide-beam units into an array to obtain a larger overall scanning range.

[0005] However, this approach has a fundamental flaw. To achieve effective beam control, the metasurface elements must have a sufficiently large electrical size (typically close to the operating wavelength), which directly forces the radiating elements to be arranged with a large spacing (usually exceeding 0.7 times the wavelength). According to phased array theory, excessively large element spacing leads to extremely small scanning angles and the appearance of grating lobes. Grating lobes mean that energy will appear simultaneously in multiple unexpected directions, completely destroying the antenna's directional radiation function and rendering it incapable of continuous, unambiguous scanning as a practical phased array. Essentially, this approach only yields a broadband antenna and cannot achieve electronic scanning functionality.

[0006] Option 2: Dense array based on complex three-dimensional decoupling structure Another mainstream approach adheres to the standard half-wavelength spacing to ensure lobe-free scanning, instead introducing complex three-dimensional structures to suppress cell mutual coupling and improve scanning impedance. These solutions take various forms, including but not limited to: constructing multi-layered stacked parasitic patch structures around the radiating cells, setting vertical metal via fences, integrating ferrite or other magnetic material substrates, or employing sophisticated differential feeding and filtering circuits. The purpose of these complex structures is to create electromagnetic isolation or a special field distribution between cells, thereby mitigating performance degradation during large-angle scanning.

[0007] Such solutions come at an extremely high cost. The complex multi-layer stacking, vertical structure, special materials, and associated precision machining processes lead to soaring antenna manufacturing costs, decreased production yields, and significantly increased profile thickness. A typical three-dimensional decoupling array used for wide-angle scanning often has a total thickness reaching a quarter or even more of the operating wavelength, requiring expensive multi-layer board lamination, laser drilling, or thin-film deposition processes. This not only contradicts the modern trend towards thinner and more integrated wireless devices but also makes such antennas difficult to apply to cost-sensitive large-scale commercial scenarios, such as 5G base stations or consumer terminals. Furthermore, the design optimization cycle for complex structures is lengthy, performance is sensitive to manufacturing tolerances, and consistency and reliability challenges arise during large-scale array expansion.

[0008] The two aforementioned technical approaches present a distinct dilemma: the first approach (large-pitch metasurfaces), while relatively simple in structure, cannot achieve true grating-lobe-free wide-angle scanning due to its inherent limitations; the second approach (complex three-dimensional structures), although achieving some improvement in electrical performance, comes at the cost of unacceptable structural complexity, cost, and profile. This profound contradiction between "performance and manufacturability" has long constrained the application of wide-angle scanning phased arrays on low-cost, high-integration platforms. Summary of the Invention

[0009] To address the problems existing in the prior art, this invention provides a metasurface phased array antenna with broadband high gain and low radar cross section. Within the boundaries of standard printed circuit board (PCB) technology, it achieves grating-lobe-free wide-angle scanning, broadband high-gain radiation, and low radar cross section of a dense array through a simple, low-profile, and low-cost planar multilayer structure.

[0010] To achieve the above objectives, the present invention provides the following solution: A metasurface phased array antenna with broadband high gain and low radar cross section includes: a ground plane, a second dielectric substrate layer, a metasurface layer, a first dielectric substrate layer and a radiating patch layer connected sequentially from bottom to top; by integrating a subwavelength metasurface under the radiating layer, a low-profile antenna structure that simultaneously achieves wide-angle stable scanning, broadband high-gain radiation and broadband radar cross section reduction is realized.

[0011] Preferably, the ground plane surface integrates 16 independent coaxial feed ports; each port is directly connected to an external CNC phase shifter channel via an independent coaxial cable, and electronic scanning of the antenna beam is achieved by precisely controlling the phase shift of each channel.

[0012] Preferably, the second dielectric substrate layer uses F4BM265 substrate material, which has a relative permittivity ε r The loss angle is approximately 2.65, the loss tangent is approximately 0.002, and the thickness is 3.5 mm.

[0013] Preferably, the metasurface layer is composed of a periodically arranged array of subwavelength metal patch units; wherein, the metasurface unit is an arrow copper patch plus two small square copper patches, the center-to-center distance between adjacent units is p=9.0mm, and the distance is 0.096λ0, where λ0 is the operating wavelength.

[0014] Preferably, the first dielectric substrate layer is made of F4BM265 material with a thickness of 3.0 mm; wherein, the selection of the thickness and dielectric constant of the first dielectric substrate layer is used to optimize the operating frequency and bandwidth of the radiating patch and to adjust the coupling strength between the radiating patch and the metasurface.

[0015] Preferably, the radiating patch layer consists of 4×4 elliptical metal radiating patches, each with a rectangular slot in the center, arranged periodically in a rectangular grid. The center of each radiating patch is connected to the feed point of the bottom layer through a metallized via that passes through the gap between the first and second dielectric substrates and the metasurface layer, thus achieving coaxial back feed.

[0016] Preferably, the radiating patch is an elliptical slotted copper patch with a long side of 27 mm and a short side of 5 mm; the center-to-center distance between adjacent patches is d = 36 mm, which is approximately 0.408λ0, and is approximately 0.5 times the waveguide wavelength in a dielectric environment.

[0017] Preferably, the following performance combination is also met: scanning range ≥ ±58°; gain drop ≤ 3dB at the maximum scanning angle; impedance bandwidth (S11 < -10dB) 18%; profile only 0.07λ0; within the operating frequency band, for vertically incident cross-polarized waves, single-station RCS reduction ≥ 8dB, x-polarization reduction frequency band in 9.1-22.7GHz with a relative bandwidth of 85.5%; y-polarization reduction frequency band in 7.7-22.1GHz with a relative bandwidth of 96.3%.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The low-profile, wide-angle scanning metasurface integrated phased array antenna of this invention employs a composite radiator structure consisting of a radiating patch layer and a subwavelength metasurface layer. With an ultra-low profile of only 0.07 times the wavelength (6.5mm@3.4GHz), it achieves ±58° grating-lobe-free scanning (gain drop of only 2.6dB) and 18% impedance bandwidth in the 2.9-3.5GHz frequency band, while also producing a >10dB backward RCS reduction for cross-polarized waves. This invention optimizes both scanning performance and stealth characteristics through the synergistic design of metasurfaces, and utilizes modular assembly and a direct-connection feed interface, combining high performance, low cost, and easy integration advantages, making it suitable for advanced radar, communication, and stealth platforms. Attached Figure Description

[0019] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of a metasurface phased array antenna with wide bandwidth, high gain, and low radar cross section according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the metasurface layer structure; Figure 3 This is a schematic diagram of the structure of the radiation patch layer; Figure 4 A scaled-down RCS plot of x-polarization; Figure 5 A scaled-down RCS plot of y-polarized data; Figure 6 The results are the impedance bandwidth simulation results; Figure 7 The results are the simulation results of the antenna array gain; Figure 8 Simulation results of the xoz plane scan angle (3GHz); Figure 9 The simulation results for the yoz plane scan angle (3GHz) are shown. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Example 1 like Figure 1 As shown, the present invention provides a metasurface phased array antenna with broadband high gain and low radar cross section, which is manufactured using standard multilayer printed circuit board (PCB) technology; the antenna includes: a ground plane, a second dielectric substrate layer, a metasurface layer, a first dielectric substrate layer and a radiating patch layer connected sequentially from bottom to top.

[0024] Furthermore, the ground plane not only serves as electromagnetic shielding and a reference ground, but its surface also integrates 16 independent coaxial feed ports. Each port is directly connected to an external CNC phase shifter channel via an independent coaxial cable. By precisely controlling the phase shift of each channel, electronic scanning of the antenna beam is ultimately achieved.

[0025] Furthermore, the second dielectric substrate layer is located above the ground plane and below the metasurface layer. The second dielectric substrate layer uses F4BM265 substrate material with a relative permittivity ε. r The loss tangent tanδ≈0.002, with a thickness of 3.5mm, is approximately 2.65. The second dielectric substrate layer and the metasurface layer together determine the equivalent electromagnetic parameters of the metasurface unit, which is key to achieving specific dispersion characteristics.

[0026] Furthermore, such as Figure 2 As shown, the metasurface layer consists of a periodically arranged array of subwavelength metal patch units. In this embodiment, the 4×4 array has 16 metasurface units arranged below each radiating patch, for a total of 16×16=256 units. Each metasurface unit is an arrow-shaped copper patch surrounded by two small square copper patches, with a center-to-center spacing (period) of p=9.0mm between adjacent units. This period is much smaller than the operating wavelength (λ0=88.23mm), approximately 0.102λ0, which is a typical subwavelength structure. The metasurface layer is the core functional layer for achieving wide-angle scanning, broadband characteristics, and low RCS.

[0027] Furthermore, the first dielectric substrate layer is located between the metasurface layer and the radiating patch layer. It also uses F4BM265 substrate with a thickness of 3.0 mm. The selection of the thickness and dielectric constant of the first dielectric substrate layer is used to optimize the operating frequency and bandwidth of the radiating patch and to adjust the coupling strength between the radiating patch and the metasurface.

[0028] Furthermore, such as Figure 3As shown, the radiating patch layer consists of 4×4 elliptical metal radiating patches arranged periodically in a rectangular grid pattern, each with a central rectangular slot. The radiating patches are elliptical slotted copper patches with a long side of 27 mm and a short side of 5 mm. The center-to-center spacing (i.e., cell spacing) between adjacent patches is d = 36 mm. This spacing is approximately 0.408λ0, which in a dielectric environment is approximately 0.5 times the waveguide wavelength (λg), representing the maximum permissible spacing to ensure grid-lobe-free scanning. The center of each radiating patch is connected to the feed point of the underlying layer via a metallized via that penetrates the gap between the first and second dielectric substrates and the metasurface layer, achieving coaxial back-feedback.

[0029] Total thickness: H = h1 + h2 = 3.0 mm + 3.5 mm = 6.5 mm, which is only about 0.007 times the free space wavelength λ0, achieving an extremely low profile; where H represents the total thickness of the antenna; h1 represents the thickness of the first dielectric substrate layer; h2 represents the thickness of the second dielectric substrate layer; the metal thickness is negligible.

[0030] Each radiating patch, in its vertical projection, precisely covers the area composed of 4×4 metasurface units below it. This one-to-many mapping relationship is the basis for the precise control of the radiating units by the metasurface energy.

[0031] The power feed vias originate from the feed point on the ground plane, pass vertically upwards through the gap between the second dielectric substrate and the metasurface unit (to avoid short-circuiting with the metasurface), then pass through the first dielectric substrate, and finally connect to the center of the radiating patch. All vias maintain a safe distance from the metasurface unit.

[0032] The ground plane, second dielectric substrate layer, metasurface layer, first dielectric substrate layer and radiating patch layer of the present invention are mechanically assembled by non-metallic fasteners (such as nylon screws) through through holes, realizing a separable, adjustable and low-cost assembly method.

[0033] Furthermore, the antenna of the present invention simultaneously satisfies the following performance combination: scanning range ≥ ±58°; gain drop ≤ 3dB at the maximum scanning angle; impedance bandwidth (S11 < -10dB) 18%; profile only 0.07λ0; within the operating frequency band, for vertically incident cross-polarized waves, single-station RCS reduction ≥ 8dB, x-polarization reduction frequency band is 9.1-22.7GHz with a relative bandwidth of 85.5%; y-polarization reduction frequency band is 7.7-22.1GHz with a relative bandwidth of 96.3%.

[0034] To fully verify the technical effects achieved by the present invention, a systematic simulation analysis of the antenna structure described in this embodiment was performed using the three-dimensional full-wave electromagnetic simulation software CSTMicrowave Studio. The following details the establishment of the simulation environment, parameter settings, solution process, and post-processing of the results to demonstrate the authenticity and reproducibility of the performance claimed by the present invention.

[0035] I. Simulation Environment Setup and Solver Configuration Model building: based on Figure 1 The structural dimensions and material parameters shown were accurately created in the CST Microwave Studio 2023 environment to form a 3D model. All geometric dimensions strictly follow the description in the embodiment.

[0036] Material definition: Metallic layers: Radiation patches, metasurface unit arrays, and ground planes are all defined as perfect electrical conductors (PEC).

[0037] Dielectric substrate: Both the first and second dielectric layers are defined as uniform, isotropic dielectric materials with a relative permittivity of 2.65 and a loss tangent of 0.002.

[0038] Boundary conditions: To simulate the antenna array environment and efficiently calculate its active performance, the X and Y directions are set to "Open (addspace)" boundaries to simulate the infinite periodicity of the array in the corresponding directions; the Z direction (wave propagation direction) is set to "Open (addspace)" boundary, and sufficient air layers are added to simulate free space radiation.

[0039] This setting allows for the direct calculation of the active reflection coefficient and radiation field of the array at a specified scan angle (by setting the transverse wave vectors Kx and Ky) by defining the Floquet mode excitation.

[0040] Incentive settings: For radiation performance (e.g., scanning) simulations, the "Floquet Port" excitation is used. This port automatically excites all propagating Floquet modes and specifies the beam scanning direction (θ, φ) of the array by setting the transverse wavenumber (k_t=k0*sin(θ)*[cos(φ),sin(φ)]).

[0041] For radar cross section (RCS) simulation, the "Plane Wave" excitation source is used, which is set to be incident perpendicularly from the negative Z direction, and the polarization direction is set to the x and y directions respectively, to simulate the illumination of threat radar waves with different polarizations.

[0042] Solver selection and mesh settings: Simulations were performed using CST's Transient Solver. This solver is suitable for analyzing the broadband characteristics of this structure.

[0043] Mesh generation employs an adaptive mesh refinement technique. The initial mesh is set to at least 20 mesh elements per wavelength, with local mesh refinement performed at the interface between the metal thin layer and the dielectric. The simulation runs the adaptive refinement process until the S-parameter energy difference between two consecutive refinements meets a preset convergence criterion (typically set to 2%).

[0044] II. Simulation Process and Results of Radar Cross Section (RCS) Performance To quantitatively assess the low detectability of the antenna, a single-station RCS simulation was performed.

[0045] Simulation configuration: Create a "scattering field" simulation task in CST that includes the complete antenna structure. Remove all internal port excitations.

[0046] Set up a plane wave excitation source with its propagation direction perpendicular to the antenna aperture surface (along the -Z direction), covering a frequency range of 5GHz to 25GHz. Perform two independent simulations: one with the electric field polarization direction along the x-axis (x-polarization), and the other with the electric field polarization direction along the y-axis (y-polarization).

[0047] In the far-field monitor, a special far-field probe direction is set up to calculate backscattering, which is opposite to the direction of the incident wave (i.e., along the +Z direction).

[0048] To clearly demonstrate the RCS reduction effect, an additional simulation of the RCS of an ideal metal plate with the exact same antenna ground plane size was performed under identical simulation settings (frequency, incident angle, mesh, and backward viewing direction) as a performance comparison benchmark.

[0049] After the simulation is completed, the curve of the difference (unit: dBsm) between the antenna model of the present invention and the ideal metal plate model in the backward observation direction is post-processed as a function of frequency.

[0050] Plotting the RCSR curves on the same coordinate system forms a shape like... Figure 4 (x-polarization) and Figure 5 The comparison diagram shown is for (y-polarization).

[0051] Figure 4 (x-polarization) shows that, in the wide frequency range of 5 GHz to 25 GHz, as can be seen from the figure, the RCS value of the present invention is significantly lower than the comparison benchmark, and the RCS reduction is always more than 8 dB.

[0052] Figure 5 (y-polarization) shows that, for y-polarized incident waves, the antenna of this invention also exhibits effective RCS reduction. The RCS value is generally reduced throughout the entire frequency band, and the RCS reduction is consistently greater than 8 dB.

[0053] The simulation results directly demonstrate that the metasurface structure designed in this invention can effectively suppress the scattering of vertically incident electromagnetic waves over a wide frequency band, and possesses excellent broadband stealth characteristics.

[0054] III. Radiation Performance Simulation Process and Results To verify the antenna's radiation performance, radiation parameter simulations were performed.

[0055] Impedance-bandwidth simulation: To simulate antenna radiation in free space, all six faces of the simulation domain were set to "Open (add space)" boundary conditions to simulate infinite free space and avoid interference from reflections on the simulation results. The scan angle θ = 0° (normal direction) was set, and excitation was performed using a Floquet Port. The parameter scan was set to a frequency range of 3.0 GHz to 4.0 GHz.

[0056] After simulation, the curve of the active reflection coefficient changing with frequency is extracted.

[0057] Figure 6 The curve is shown. The graph clearly indicates the frequency range where the active reflection coefficient is less than -10dB (i.e., VSWR < 2). Measurements show this range extends from 3.1GHz to 3.7GHz, with an absolute bandwidth of 600MHz. Based on this, the relative impedance bandwidth is calculated to be 18%, demonstrating the broadband matching characteristics of this invention.

[0058] Antenna gain simulation: In the same task of completing the impedance bandwidth simulation, a far-field monitor is set up to calculate the far field in the normal direction (θ=0°, φ=0°).

[0059] After simulation, the curve of actual gain versus frequency in that direction is extracted.

[0060] Figure 7 The gain curve is shown. It can be seen that the gain curve is flat and remains high within the operating frequency band of 2.6 GHz to 4.0 GHz. The peak gain reaches 15.3 dBi and remains above 12.3 dBi for most frequency bands (>3 dB gain bandwidth from 2.85 GHz to 4 GHz, with a relative bandwidth of 33.8%), confirming that the antenna has high and stable radiation efficiency over a wide frequency range.

[0061] IV. Beam Scanning Performance Simulation: To verify the scanning capability, while keeping the original boundary condition settings, different beam pointing angles were set by changing the transverse wavenumber (k_t) of the Floquet Port excitation.

[0062] At a center frequency of 3.4 GHz, scanning simulations were performed in the xoz plane (φ=0°, H plane) and the yoz plane (φ=90°, E plane). The scanning angle θ was given to vary from 0° (normal) in 30° increments to ±60°.

[0063] For each scanning angle, the 3D far-field radiation pattern data is simulated and saved. During post-processing, the 2D cross-sectional radiation patterns of the xoz and yoz planes are extracted separately.

[0064] Appendix Figure 8 The normalized pattern overlay curves of the xoz plane (H plane) at 3.0 GHz with scan angles of 0°, ±30°, and ±60° are shown.

[0065] Figure 9 The scan pattern of the yoz plane (E plane) under the same conditions is shown.

[0066] Results analysis: such as Figure 8 and Figure 9 As shown, throughout the entire scanning process from the normal to ±60°, the main lobe shape is clear and without severe distortion, and no grating lobes were observed at any of the illustrated angles (the sidelobe level is lower than the main lobe). This demonstrates that the antenna array of the present invention can achieve effective, grating-lobe-free electronic beam scanning of at least ±60° in both principal planes, exhibiting excellent wide-angle coverage capability.

[0067] Through the rigorous and reproducible simulation process established in CST as described above, the key performance characteristics of the 4×4 metasurface integrated phased array antenna described in this embodiment of the invention have been fully verified. Simulation results ( Figures 4-9 The simulation results are highly consistent with theoretical expectations, fully demonstrating that the technical solution described in this invention can synergistically achieve broadband (18%), high gain (>15dBi), wide-angle scanning (±60° without grid lobes), and significantly low RCS characteristics (RCS reduction >8dB). These simulation data provide a solid and credible basis for the beneficial effects claimed by this invention. Those skilled in the art can reproduce the performance of this invention based on the disclosed embodiment parameters and the simulation method.

[0068] This invention has the following characteristics: 1. Composite radiator structure with metasurface-radiative unit synergy The "composite radiator" is composed of an upper radiating patch unit and a 4×4 subwavelength metasurface unit arranged below it. The spacing between the radiating patch units is a standard half-wavelength (0.4λ0-0.55λ0), while the period of the metasurface unit below it is subwavelength (less than 0.15λ0). The two are separated by two dielectric substrates, forming a strong electromagnetic coupling in the vertical direction.

[0069] 2. Construction of a wide-angle scanning array based on this composite radiator A phased array antenna, constructed by periodically arranging multiple of the aforementioned "composite radiators" at standard half-wavelength intervals, can maintain a grating lobe-free state and a gain drop of less than 3dB within a scanning range of 0° to ±55°. With an array element spacing of 36mm and a total profile thickness of less than 0.1λ0, it achieves a groundbreaking combination of "small spacing, low profile, and true wide angle."

[0070] 3. Collaborative Design of Multifunctional Metasurfaces The subwavelength metasurface unit is designed to have the following dual electromagnetic response characteristics: As an active impedance matching and wavefront compensator: during array scanning, the changes in its equivalent electromagnetic parameters (ε_eff, μ_eff) can compensate for the changes in the active impedance of the unit caused by mutual coupling and correct large-angle wavefront distortion.

[0071] As a broadband RCS reducer, its resonant structure with the underlying ground plane can produce significant broadband backscattering interference cancellation for vertically incident electromagnetic waves (especially cross-polarized waves) within the operating frequency band.

[0072] The embodiments of the present invention solve the following technical problems: 1. The scanning performance has a fundamental flaw. While existing large-pitch metasurface array schemes employ a two-layer structure, their design philosophy contains a fundamental contradiction. To achieve beam control of the radiating elements by the metasurface, these schemes use a spacing far exceeding 0.7 times the wavelength. According to the basic principles of phased arrays, this large spacing directly leads to a very small scanning angle and severe grating lobe problems, causing the antenna to completely lose its directional radiation capability. Essentially, this scheme mechanically arrays wide-beam elements rather than creating a true electronically scanned array, thus failing to meet beam scanning requirements.

[0073] This invention provides a truly usable wide-angle scanning phased array antenna based on standard half-wavelength spacing. Through innovative subwavelength metasurface design, this invention achieves grating-lobe-free continuous scanning of ±58° while maintaining a dense arrangement of 36mm (approximately 0.40λ), solving the core problem that large-spacing solutions cannot be practically implemented due to physical limitations.

[0074] 2. Complex structure and high cost While existing complex 3D decoupling array solutions improve scanning performance through multi-layer stacking, vertical metallized vias, and magnetic material integration, these complex structures lead to serious engineering problems. Antenna profile thickness typically exceeds 0.25λ, requiring expensive special materials and precision machining processes, resulting in extremely high manufacturing costs and unreliable production yields. Such designs not only contradict the modern trend towards thinner and more integrated devices but also make them unsuitable for cost-sensitive large-scale commercial applications.

[0075] The antenna of this invention has a total thickness of only 6.5 mm (approximately 0.07λ0), employs a conventional F4BM265 dielectric substrate and a fully planar structure design, requiring no three-dimensional machining or special materials. This design significantly reduces manufacturing costs and process complexity, enabling high-performance wide-angle scanning antennas to truly achieve large-scale commercial applications.

[0076] 3. Limited functionality and lack of collaborative optimization Whether it's a wide-spacing scheme or a complex 3D scheme, the design focus is limited to the single objective of improving scanning characteristics, lacking systematic consideration of key performance aspects such as bandwidth, gain, radiation efficiency, and radar scattering characteristics. Existing schemes usually require difficult trade-offs between different performance indicators, failing to achieve wide-angle scanning while simultaneously meeting multiple requirements such as broadband operation, high-gain radiation, and low detectability, thus failing to meet the comprehensive needs of modern complex electronic systems.

[0077] Through a carefully designed metasurface layer, this invention achieves wide-angle scanning while simultaneously obtaining an 18% impedance bandwidth, a 33.8% gain bandwidth, a peak gain of 15.3 dBi, and a good broadband RCS reduction effect. The relative bandwidth of x-polarization reduction is 85.5%, and the relative bandwidth of y-polarization reduction is 96.3%, achieving a synergistic improvement of multiple key performance indicators.

[0078] 4. Poor scalability makes practical deployment difficult. Existing solutions suffer from severe scalability deficiencies. Large-pitch solutions fail completely when expanded to large arrays due to grating lobe issues; complex 3D solutions face the dual challenges of performance instability and cost overruns as array sizes increase due to structural sensitivity, high cost, and manufacturing difficulties. Neither of these solutions can be reliably used as a base module for large-scale array expansion, limiting their application in large-scale phased array systems.

[0079] The design of this invention is based on a strict periodicity principle. Its 4×4 subarray can serve as a standard module, and large-scale arrays of any size can be constructed through simple two-dimensional translation and replication. During the expansion process, the antenna's wide-angle scanning characteristics, broadband high-gain performance, and low RCS characteristics remain stable, providing a reliable technical foundation for the low-cost, high-performance realization of large-scale phased array systems.

[0080] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A metasurface phased array antenna with broadband high gain and low radar cross section, characterized in that, include: The antenna consists of a ground plane, a second dielectric substrate layer, a metasurface layer, a first dielectric substrate layer, and a radiating patch layer, connected sequentially from bottom to top. By integrating a subwavelength metasurface layer under the radiating patch layer, a low-profile antenna structure that simultaneously achieves wide-angle stable scanning, broadband high-gain radiation, and broadband radar cross-section reduction is realized. The ground plane integrates 16 independent coaxial feed ports; each port is directly connected to an external CNC phase shifter channel via an independent coaxial cable, and electronic scanning of the antenna beam is achieved by precisely controlling the phase shift of each channel. The second dielectric substrate layer uses F4BM265 substrate with a relative permittivity ε. r The loss angle is approximately 2.65, the loss tangent tanδ is approximately 0.002, and the thickness is 3.5 mm. The metasurface layer is composed of a periodically arranged array of subwavelength metal patch units; wherein, the metasurface unit is an arrow copper patch plus two small square copper patches, the center-to-center distance between adjacent units is p=9.0mm, and the distance is 0.096λ0, where λ0 is the operating wavelength; The first dielectric substrate layer uses F4BM265 material with a thickness of 3.0 mm. The selection of the thickness and dielectric constant of the first dielectric substrate layer is used to optimize the operating frequency and bandwidth of the radiating patch and to adjust the coupling strength between the radiating patch layer and the metasurface layer. The radiating patch layer consists of 4×4 elliptical metal radiating patches, with a rectangular slot in the center arranged periodically in a rectangular grid. The center of each elliptical metal radiating patch is connected to the feed point of the bottom layer through a metallized via that passes through the gap between the first and second dielectric substrates and the metasurface layer, thus achieving coaxial back feed. The elliptical metal radiating patch is an elliptical slotted copper patch with a long side of 27mm and a short side of 5mm. The center-to-center distance between adjacent patches is d=36mm, which is approximately 0.408λ0, and in a dielectric environment, it is approximately equal to 0.5 times the waveguide wavelength.

2. The metasurface phased array antenna with broadband high gain and low radar cross section as described in claim 1, characterized in that, It simultaneously meets the following performance combination: scanning range ≥ ±58°; gain drop ≤ 3dB at maximum scanning angle; impedance bandwidth (S11 < -10dB) 18%; profile only 0.07λ0; within the operating frequency band, for vertically incident cross-polarized waves, single-station RCS reduction ≥ 8dB, x-polarization reduction frequency band is 9.1-22.7GHz with a relative bandwidth of 85.5%; y-polarization reduction frequency band is 7.7-22.1GHz with a relative bandwidth of 96.3%.

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