Resonant-sensitive structure, fully polarized 360° tunable reflection phase coded metasurface device and its applications

Abstract

This invention discloses a resonant-sensitive structure, a fully polarized 360° tunable reflection phase coded metasurface device, and its applications. This fully polarized 360° tunable reflection phase coded metasurface device achieves continuous phase adjustment based on an electrically controlled varactor diode. The dual-resonant structure effectively broadens the resonant phase response, enabling continuous 360° phase modulation of the fully polarized reflection phase with low loss (within -2dB electromagnetic loss). Furthermore, the controllability of individual units provides excellent hardware support for achieving comprehensive control of complex beams, showing broad application prospects in future wireless communication.

Description

Technical Field

[0001] This invention specifically relates to a resonant sensitive structure, a fully polarized 360° tunable reflection phase coded metasurface device and its application method, belonging to the field of electromagnetic metamaterials. Background Technology

[0002] Electromagnetic metamaterials are artificial composite materials with extraordinary physical properties, composed of periodic or quasi-periodic unit cells. By adjusting the size, shape, and spatial distribution characteristics of the unit cell structure, the electromagnetic parameters of the material can be precisely controlled, thereby effectively manipulating the radiation, scattering, and propagation behavior of electromagnetic waves in space. Phase control of electromagnetic waves on surfaces is of great significance in fundamental electromagnetic research and device technology. Many phenomena and applications are related to phase control, such as electromagnetic propagation mode to surface mode conversion, anomalous reflection, electromagnetic wave absorbers, high-impedance surfaces and artificial magnetic conductors, reflecting antennas, beamforming and beam-scanning antennas, phase shifters, etc. In most of these applications, full phase control over the 360° range is typically required.

[0003] Passive metasurfaces typically achieve phase control by altering the dimensions of the metal resonator. For reflective metasurfaces, a 360° overall phase tuning effect can be easily achieved by adding an additional 180° phase shift provided by a perfectly conductive surface (PEC). However, once a passive metasurface is fabricated, its properties are fixed. Tunable elements include temperature-tunable phase-change materials, electrically tunable graphene, active microwave components (such as PIN diodes and varactor diodes), and mechanical tuning methods, depending on the operating frequency and application.

[0004] In the microwave band, PIN diodes and varactor diodes are frequently used as electrically tunable devices to control electromagnetic response. Currently, tunable metasurface devices have been extensively studied; however, due to limitations such as the parameter range of commercially available diode devices, most designs cannot effectively achieve continuous tunability across the entire 360° phase (most can only achieve phase control of around 340°). Even if tunable, they face problems such as high reflection loss or single polarization (e.g., one or more linear or circular polarizations). Few device structures can support full polarization, arbitrary polarization, and achieve continuous dynamic control of the 360° reflection phase under low-loss conditions. Therefore, as a highly flexible and scarce technology, further research into its design and optimization methods is essential.

[0005] The tunability of an active metasurface typically depends on the range of controllable parameters of the selected tunable element and the structural response of the metasurface metallic resonator. The combination of these two factors should maximize the tuning range of the phase parameter.

[0006] Currently in the microwave band, PIN diodes and varactor diodes are frequently used as electrically tunable devices to control electromagnetic response. However, most existing unit structures cannot effectively achieve full 360° phase coverage. Even if it is possible, problems such as high reflection loss or single polarization are encountered. Very few device structures can support full polarization, arbitrary polarization, and dynamic 360° reflection phase control under low-loss conditions. Summary of the Invention

[0007] The main objective of this invention is to provide a resonant sensitive structure, a fully polarized 360° tunable reflection coded metasurface device and its application, which can achieve continuous phase modulation with low loss (within -2dB electromagnetic loss), providing good hardware support for real-time controllability of complex beams, thereby overcoming the shortcomings of the prior art.

[0008] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0009] A first aspect of the present invention provides a resonant sensitive structure comprising:

[0010] A dielectric substrate layer, comprising a top dielectric substrate and a bottom dielectric substrate stacked together;

[0011] A metal grounding reflective layer is stacked between the top dielectric substrate and the bottom dielectric substrate, and serves as a feed electrode and an electromagnetic wave reflector.

[0012] A resonant layer is stacked on the underlying dielectric substrate. The resonant layer includes a square metal patch and four pad groups surrounding the square metal patch. The four pad groups correspond to the four sides of the square metal patch and are electrically connected to the square metal patch.

[0013] Two first metallized via groups penetrate the square metal patch and the top dielectric substrate, and are electrically connected to the square metal patch and the metal ground reflective layer, respectively. The two first metallized via groups are arranged along the x and y directions, respectively, and form an orthogonal resonant cavity separation structure. The minimum distance N between the two first metallized via groups and the edge of the square metal patch is equal. The first metallized via groups have no direct contact with the pad group. The x and y directions are the side length directions of the square metal patch. The two first metallized via groups can respond to horizontally polarized and vertically polarized electromagnetic waves, respectively.

[0014] The second metallized via group is distributed around the square metal patch. The second metallized via group penetrates the top dielectric substrate and the bottom dielectric substrate. One end of the second metallized via group is electrically connected to the pad group, and the other end extends to the lower surface of the bottom dielectric substrate to form an external power supply port. The second metallized via group is electrically isolated from the metal ground reflective layer.

[0015] Furthermore, the first metallized via group includes a plurality of first metallized vias, and the plurality of first metallized vias included in each first metallized via group are arranged at intervals along the side length direction of the square metal patch.

[0016] Furthermore, the ratio of the minimum distance N between the first metallized via group and the edge of the square metal patch to the side length L of the square metal patch is (0.5~2):(6~10).

[0017] Furthermore, the ratio of the diameter D1 of the first metallized via, the spacing d between adjacent first metallized vias, and the side length L of the square metal patch is (0.2~0.3):(0.5~1.5):(6~10).

[0018] Furthermore, the four pad groups are centrally symmetrically distributed around the square metal patch.

[0019] Furthermore, the pad group includes a plurality of pads arranged at intervals along a direction away from the square metal patch, the pads being parallel to the square metal patch.

[0020] Furthermore, the ratio of the length M of the pad to the side length L of the square metal patch is (2~4):(6~10).

[0021] Furthermore, the second metallized via group includes four second metallized vias, each of which corresponds to one of the pad groups.

[0022] Furthermore, the diameter D2 of the second metallized via is smaller than the width of the pad.

[0023] Furthermore, each of the second metallized vias is located in the geometric center region of one of the pad groups.

[0024] Furthermore, the resonant sensitive structure is generally square, and the side length of the square metal patch is less than or equal to the period length P of the resonant sensitive structure.

[0025] Furthermore, the ratio of the period length P of the resonant sensitive structure to the side length L of the square metal patch is (10~20):(6~10).

[0026] Furthermore, the resonant layer has a centrosymmetric structure.

[0027] Furthermore, the resonant sensitive structure is a mirror-symmetric structure, and the axis of symmetry of the resonant sensitive structure coincides with one diagonal of the square metal patch and passes through the orthogonal intersection of the two first metallized via groups.

[0028] A second aspect of the present invention provides a fully polarized 360° reflective phase-tunable coded metasurface device, comprising a plurality of digital coding units periodically arranged and electrically connected in sequence in the x and y directions;

[0029] The digital encoding unit includes the resonant sensitive structure and four varactor active devices. The four varactor active devices are respectively disposed on the four pad groups. Each varactor active device is electrically connected to the square metal patch and a pad group. Each digital encoding unit can be individually controlled by a bias voltage applied to the varactor active device and can switch between different operating states. A first resonant cavity or a second resonant cavity is formed between the two resonant cavity separation structures of two adjacent digital encoding units. The first resonant cavity and the second resonant cavity have different sizes.

[0030] Furthermore, the digital encoding unit also includes four fixed capacitor elements, and the four fixed capacitor element groups are respectively disposed on the four pad groups, and each fixed capacitor element is connected in series with a varactor active device.

[0031] Furthermore, a second fixed capacitor element and a varactor active device electrically connected to one of the pad groups are located on both sides of a second metallized via connected to the pad group.

[0032] Furthermore, the varactor active device includes a varactor diode.

[0033] Furthermore, the multiple digital encoding units are combined into multiple subarrays, each subarray comprising 2×2 digital encoding units arranged in a mirror pattern, and each subarray having a centrally symmetric structure.

[0034] A third aspect of the present invention provides a method for achieving fully polarized 360° tunable reflection phase, comprising: providing the fully polarized 360° tunable reflection phase coded metasurface device, and independently applying a bias voltage to a plurality of varactor active devices in each of the digital coding units.

[0035] In a more specific implementation, a method for realizing a fully polarized 360° tunable reflection phase coded metasurface device includes the following steps:

[0036] Step 1: Using printed circuit board (PCB) technology, an axisymmetric and centrally symmetrical patch metal resonant structure (i.e., resonant sensitive structure) is formed on a commercial dielectric substrate to form the basic single resonant structure.

[0037] Step 2: Form an array of metallized vias on the patch-type metal resonant structure to divide the patch-type single resonator, thereby forming a dual resonator structure; the metallized vias can affect the electromagnetic response of the vertically polarized beam by being arranged horizontally, and affect the electromagnetic response of the horizontally polarized beam by being arranged vertically.

[0038] Step 3: Solder components such as varactor diodes onto the pads of the surface-mount metal resonant structure to achieve an electrically adjustable capacitor.

[0039] Step 4: The power supply portion of the metasurface is led out from the metallized via on the back side with a lead wire and connected to the control platform to achieve the effect of individual unit controllability.

[0040] Compared with the prior art, the advantages of the present invention include:

[0041] This invention provides a tunable metasurface device with arbitrarily polarized controllable 360° reflection phase full coverage. It adopts a dual-resonant structure to broaden the bandwidth and achieves continuous phase adjustment based on an electrically controlled varactor diode. It can achieve continuous phase control of full polarization with low loss (within -2dB electromagnetic loss).

[0042] This invention provides a tunable metasurface device with arbitrarily controllable polarization and 360° full reflection phase coverage. It can effectively control all polarizations, and each digital coding unit can be individually controlled. By arbitrarily arranging and combining unit subarrays and feeding in different regions, it can effectively achieve real-time controllable effects for complex beams, and has broad application prospects in the future field of wireless communication. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the beam control effect of a fully polarized 360° reflective phase-tunable coded metasurface device provided in a typical embodiment of the present invention.

[0044] Figure 2a This is a perspective view of a digital encoding unit of a fully polarized 360° reflective phase-tunable encoded metasurface device provided in a typical embodiment of the present invention;

[0045] Figure 2b This is a top view of the top metal patch antenna of the digital coding unit in a typical embodiment of the present invention;

[0046] Figure 2cThis is a schematic diagram of the metal ground plane of the metal grounding reflective layer in the middle of a typical embodiment of the present invention;

[0047] Figure 2d This is a schematic diagram of the back structure of the bottom dielectric substrate in a typical embodiment of the present invention;

[0048] Figure 3a This is a schematic diagram of the arrangement structure of the smallest unit subarray in a fully polarized 360° reflective phase-tunable coded metasurface device provided in a typical embodiment of the present invention;

[0049] Figure 3b This is a schematic diagram of the array arrangement structure of a fully polarized 360° reflective phase-tunable coded metasurface device provided in a typical embodiment of the present invention;

[0050] Figure 3c This is a schematic diagram of the structure of a fully polarized 360° reflective phase-tunable coded metasurface device provided in a typical embodiment of the present invention, consisting of two resonant cavities of different sizes made of a first metallized via group and metals on both sides of the substrate dielectric substrate layer.

[0051] Figure 3d This is a perspective view of the array arrangement of a fully polarized 360° reflective phase-tunable coded metasurface device provided in a typical embodiment of the present invention;

[0052] Figure 4a , Figure 4b This is a schematic diagram of a feeding control grouping method for a fully polarized 360° reflective phase-adjustable coded metasurface device with different polarization states, provided in a typical embodiment of the present invention.

[0053] Figure 5a , Figure 5b These are numerical simulation curves showing the changes in reflection coefficient and reflection phase as a function of the applied reverse working voltage of a varactor diode when a plane electromagnetic wave with a frequency of 2-5 GHz is perpendicularly incident on a fully polarized 360° tunable coded metasurface device.

[0054] Figure 6a , Figure 6b This is a typical embodiment of the present invention that implements beam control using a 1-bit encoding method;

[0055] Figure 7a , Figure 7b This is a typical embodiment of the present invention that implements beam control using a multi-bit hybrid coding method. Detailed Implementation

[0056] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate the technical solution, its implementation process, and its principles in conjunction with the accompanying drawings and specific embodiments.

[0057] Active metamaterials overcome the limitations of fixed electromagnetic functions in traditional passive metamaterials, enabling the cancellation of dielectric losses, modulation of electromagnetic resonance response intensity, and widening of operating bandwidth, thus significantly expanding the applicability of metamaterials. The tunability of active metasurfaces typically depends on the controllable parameter range of the selected tunable element and the loop response of the metasurface metal resonator; the combination of these two factors must maximize the tuning range of the phase parameters. In the microwave band, PIN diodes and varactor diodes are frequently used as electrically tunable devices to modulate the electromagnetic response. However, most of the currently studied unit structures cannot achieve full 360° phase coverage. Even if this is possible, it inevitably comes with drawbacks such as high reflection losses or the inability to achieve tunability for a single polarization (e.g., a linear or circular polarization). Few device structures can support full polarization, arbitrary polarization, and continuous dynamic modulation of the 360° reflection phase under low-loss conditions.

[0058] This invention aims to improve the phase tunability range of reflective metasurfaces and reduce reflection loss. It proposes a tunable control method with arbitrarily polarized, 360° full-coverage reflection phase. The proposed active metasurface employs a multi-resonant structure to broaden the bandwidth and utilizes an electrically controlled varactor diode to achieve continuous phase tunability. It enables continuous phase control of all polarizations with low loss (within -2dB electromagnetic loss), providing excellent hardware support for real-time controllable effects of complex beams. It has broad application prospects in the future field of wireless communication.

[0059] This invention provides a fully polarized 360° tunable reflective coded metasurface device. It employs a multi-cavity resonant structure to extend bandwidth and utilizes an electrically controlled varactor diode to achieve continuous phase tunability. This device exhibits excellent electrical control performance, effectively broadening the phase control range of reflective metasurfaces and achieving low reflection loss. Correspondingly, a control method for this arbitrarily polarized, 360° fully tunable reflective coded metasurface is proposed. This method enables continuous phase control of a single unit with narrowband full polarization under low loss conditions (within -2dB electromagnetic loss). It supports independent control of electromagnetic waves with different polarizations to achieve diverse functions and provides excellent hardware support for real-time controllability of complex beams. It has broad application prospects in the future field of wireless communication.

[0060] For a more specific implementation plan, please refer to Figure 1A fully polarized 360° reflective phase-tunable coded metasurface device includes a metal resonant array formed by multiple periodically arranged resonant sensitive structures of the same size, on which active devices such as varactor diodes are welded. Each resonant sensitive structure and a group of varactor diodes and other active devices constitute a digital coding unit. Multiple digital coding units are closely connected along the x and y directions with zero distance. Each digital coding unit can be individually controlled by an external bias voltage to achieve switching between different operating states.

[0061] In this invention, active devices such as varactor diodes serve as dynamic control components, effectively achieving low-loss reflection within a narrow band and continuous 360° phase change control of the reflection. Under the control of the FPGA, digital encoding units at different locations can be assigned different bias voltages, thereby achieving different electromagnetic resonance responses. Through this design, when electromagnetic waves within the operating wavelength range are incident on the encoded metasurface device, the reflected electromagnetic waves can be effectively controlled, thereby generating effects such as split beams, random scattering, and vortex beams.

[0062] Please see Figures 2a-2d , Figures 2a-2d The smallest structural unit of a fully polarized 360° reflective tunable coded metasurface device—a digital coding unit—is shown. This digital coding unit includes a resonant sensitive structure and four electrically tunable device groups.

[0063] The resonant sensitive structure includes a dielectric substrate layer, a metal ground reflective layer 9, a patch antenna resonant layer (i.e., the aforementioned resonant layer, which can also be called a metal resonant layer, hereinafter the same), two first metallized via groups 5, and a second metallized via group 6.

[0064] The dielectric substrate layer includes a top dielectric substrate 7 and a bottom dielectric substrate 8 stacked along the z-direction, and a metal grounding reflective layer 9 stacked between the top dielectric substrate 7 and the bottom dielectric substrate 8 along the z-direction. The metal grounding reflective layer 9 serves as both a feed electrode and a reflector.

[0065] The patch antenna resonant layer is stacked along the z-direction on the top dielectric substrate 7. The patch antenna resonant layer includes a square metal patch 1 located in the central region and four pad groups 2. The four pad groups 2 are distributed around the square metal patch 1 and are electrically connected to the square metal patch 1.

[0066] The first metallized via group 5 penetrates the square metal patch 1 and the top dielectric substrate 7 along the z-direction, and is electrically connected to the square metal patch 1 and the metal ground reflective layer 9, respectively. The two first metallized via groups 5 are arranged along the x-direction and y-direction, respectively, to form an orthogonal resonant cavity separation structure. The second metallized via group 6 is distributed around the square metal patch 1. The second metallized via group 6 penetrates the top dielectric substrate 7 and the bottom dielectric substrate 8 along the z-direction. One end of the second metallized via group 6 is electrically connected to the pad group 2, and the other end extends to the lower surface of the bottom dielectric substrate 8 to form an external power supply port. The second metallized via group 6 is electrically isolated from the metal ground reflective layer 9. The four electrically tuned device groups are respectively disposed on the four pad groups 2 and are electrically connected to the four pad groups 2 and the square metal patch 1, respectively.

[0067] It should be noted that the x, y, and z directions correspond to the x-axis, y-axis, and z-axis directions of the three-dimensional coordinate system, respectively. The side length direction of the square metal patch 1 is parallel to the x and y directions, which can also be understood as the x and y directions being the side length directions of the square metal patch 1.

[0068] Specifically, the dielectric substrate layer can be made of various chemically stable, malleable, and perforated materials. Specifically, the dielectric substrate layer can be made of cost-effective domestically produced commercial dielectric substrate materials; for example, the dielectric substrate layer material can be polytetrafluoroethylene fiberglass cloth copper clad laminate (F4BM), etc. Specifically, the thickness H1 of the top dielectric substrate 7 is 3 mm to 5 mm, and the thickness H2 of the bottom dielectric substrate 8 is 0.5 mm to 2 mm.

[0069] Specifically, Figure 2bThe specific morphology of the patch antenna resonant layer is shown. Four pad groups 2 correspond to the four sides of the square metal patch 1 and are centrally symmetrically distributed / axially symmetrically distributed. Their symmetry axes are the two midlines / diagonals of the square metal patch 1. Each pad group 2 includes multiple metal pads arranged sequentially at intervals along the x-direction or y-direction. The metal pads are closely connected to the square metal patch 1. The metal pads and one side of the square metal patch 1 connected to them are parallel. The length M of all the metal pads is preferably equal and less than the side length L of the square metal patch 1. Each electrical tuning device group includes a varactor diode 3 and a fixed capacitor element 4. The varactor diode 3 and the fixed capacitor element 4 are arranged sequentially at intervals along the direction away from the square metal patch 1. The varactor diode 3 is electrically connected to the square metal patch 1 and the metal pads respectively. The fixed capacitor element 4 is connected in series with the varactor diode 3 through the metal pads. Specifically, the varactor diode 3 is used to change the capacitance parameters, thereby primarily altering the resonant response on the patch antenna. This results in better adjustability within the resonant sensitivity range and a wider phase modulation range. However, commercially available varactor diodes typically have a large base capacitance (usually 1-10 pF), slightly exceeding the resonant control range of the metasurface unit (i.e., the resonant sensitive structure) in this invention (the metasurface unit in this invention is highly sensitive to capacitance around 1 pF at its operating frequency). By using a series-connected fixed capacitor element 4, the overall capacitance value can be effectively reduced to within the sensitivity range, thus effectively controlling the resonant frequency and achieving wide-range phase modulation. Specifically, the four sets of electrically tuned devices are also centrally symmetrically distributed around the square metal patch 1.

[0070] Specifically, the second metallized via group 6 includes four second metallized vias, each corresponding one-to-one with one of the four pad groups 2. Each second metallized via is located at the geometric center of a pad group 2, and is positioned between a varactor diode 3 and a fixed capacitor 4 on its respective pad group 2. This position has minimal impact on the resonant circuit and is used to provide voltage bias for the diode from the back side of the underlying dielectric substrate 8. It should be noted that although the second metallized via group 6 penetrates the metal grounding reflective layer 9, it remains electrically isolated from it. Figure 2c The specific morphology of the metal grounding reflective layer 9 is shown. It can be clearly seen that the first metallized via group 5 is directly connected to the metal grounding reflective layer 9, while the second metallized via group 6 is not in contact with the metal grounding reflective layer 9 through the opening 10 on the metal grounding reflective layer 9. The first metallized via group 5 and the second metallized via group 6 are respectively connected to the positive and negative terminals of the varactor diode 3. Figure 2dThe specific morphology of the bottom dielectric substrate 8 is shown. It can be seen that only the second metallized via group 6 passes through the bottom dielectric substrate 8 and needs to be led out. Since the four output ports of the second metallized via group 6 are not connected to each other, they can be independently fed, thereby realizing the control and conversion of electromagnetic waves with different polarization modes.

[0071] Specifically, the first metallized via group 5 includes multiple first metallized vias. The multiple first metallized vias in two first metallized via groups are sequentially spaced along the x and y directions, respectively. The overall length of the two first metallized via groups is equal to the side length L of the square metal patch 1. The minimum distance N between the two first metallized via groups 5 and the edge of the square metal patch is equal. The two first metallized via groups 5 perpendicularly intersect to form an orthogonal resonant cavity separation structure. This resonant cavity separation structure divides the patch antenna resonator (i.e., the resonant sensitive structure) into two parts, forming two resonant cavities of different sizes (i.e., the first and second cavities as described in the claims) with the adjacent resonant sensitive structure. The second resonant cavity broadens the bandwidth. Simultaneously, through two arrangement methods—lateral (x-direction, the same below) and longitudinal (vertical and y-directions, the same below)—it can act on both vertically and horizontally polarized electromagnetic waves. It is particularly important to note that the two first metallized via groups 5 are entirely distributed within the orthographic projection area of ​​the square metal patch 1. The first metallized via groups 5 cannot pass through the metal pads to prevent short circuits and effectively divide the resonant cavity. Furthermore, the pad group 2 is entirely located on one side of the extension surface / line of the first metallized via group 5 along the x and y directions; that is, the two pad groups arranged opposite each other along the x and y directions are entirely located on both sides of a first metallized via group 5.

[0072] Specifically, the ratio of the minimum distance N between the first metallized via group and the edge of the square metal patch to the side length L of the square metal patch is (0.5~2):(6~10), the ratio of the diameter D1 of the first metallized via, the spacing d between adjacent first metallized vias, and the side length L of the square metal patch is (0.2~0.3):(0.5~1.5):(6~10), the ratio of the length M of the pad to the side length L of the square metal patch is (2~4):(6~10), and the diameter D2 of the second metallized via is smaller than the width of the metal pad.

[0073] Specifically, the thickness of the patch antenna resonant layer is 0.018mm or 0.036mm. The material of the patch antenna resonant layer is a good conductor material, generally made of copper, which can be plated with gold to increase performance stability, prevent corrosion and oxidation, and extend the device's lifespan.

[0074] Specifically, the digital encoding units have the same structure and size parameters, but differ in the bias voltage across the varactor diode, which controls the electromagnetic response of each digital encoding unit. Specifically, the varactor diode 3 should have a suitable adjustable capacitance range (typically adjustable on the order of 1pF, requiring selection of a suitable range based on commercially available diodes), thereby effectively altering the circuit's resonant characteristics and creating a phase change.

[0075] Specifically, the structural parameters of the fully polarized 360° tunable reflection coded metasurface device correspond to the microwave band, which can be adjusted according to the selected structural parameters. Specifically, the size of the resonant sensitive structure is smaller than or equal to the unit period P of the digital coding unit. For different wavelengths, changing the unit period P of the digital coding unit and the size of the resonant sensitive structure can achieve good reflectivity and phase control effects. For a more typical implementation example, please refer again... Figures 2a-2d The digital encoding unit has a unit period P = 10mm~20mm, the square metal patch 1 has a side length L = 6mm~10mm, the width / length M of the metal pads is 2mm~4mm, the gap G between the metal pads is generally determined by the pin pitch of the component, and the gap G between the metal pads is 0.1mm~0.3mm, the diameter D1 of the first metallized via is 0.2mm~0.3mm, and the spacing d between adjacent first metallized vias is 0.5mm~1.5mm. The first metallized via group 5 includes both horizontal and vertical arrangements, and its minimum distance N from the edge of the square metal patch 1 is the same, N = 0.5mm~2mm. The second metallized via group 6 generally needs to be able to connect external leads and cannot exceed the size of the metal pads, therefore the diameter D2 of the second metallized via is 0.4mm~0.7mm. The diameter D of the opening 10 on the metal grounding reflective layer 9 needs to be larger than the diameter of the second metallized via to avoid short circuits, but it cannot be too large and affect the reflection performance. The diameter D of the opening 10 on the metal grounding reflective layer 9 is 1mm~3mm. Based on this set of optimized parameters, the operating frequency band can be effectively adjusted, and the structure can achieve advantages such as good phase controllability and high reflection efficiency.

[0076] For details, please see Figures 3a-3d The fully polarized 360° reflective phase-tunable coded metasurface device provided in this embodiment of the invention includes multiple digital coding units arranged in an array. Specifically, the multiple digital coding units are combined into multiple subarrays. Figure 3a The arrangement structure of the smallest unit, the subarray, is shown. The subarray is formed by mirroring 2×2 digital coding units of the same structure and size, and has the characteristic of central symmetry. Figure 3bThe diagram shows a total array structure formed by the periodic repetition of multiple subarrays. The number of subarrays depends on the actual requirements, and the overall size is generally 3 to 5 operating wavelengths.

[0077] Figure 3c The diagram shows two different sizes of resonant cavity distributions formed by the first metallized via group 5 and the metal surfaces on both sides of the dielectric substrate layer (the surfaces of patch antenna 1, pad 2, and metal ground reflective layer 9). The two sizes of resonant cavities correspond to different resonant frequencies. The superposition of these two resonant frequencies can effectively broaden the bandwidth and obtain a greater phase control effect. Figure 3d A perspective view of the corresponding resonant cavity is shown, clearly revealing that the first metallized via group 5 and the metal surfaces on both sides of the dielectric substrate layer together constitute two cavities of different sizes. The top-layer pad group 2 and the varactor diode 3, as effective components participating in resonance, play a crucial role in phase control; therefore, simply changing the state of the varactor diode 3 can affect the resonance of the resonant cavity. Furthermore, horizontally polarized (x-polarization) and vertically polarized (y-polarization) electromagnetic waves correspond to the horizontal and vertical resonant cavities, respectively, enabling broadband and effective control of waves with different polarizations.

[0078] Please see Figure 4a , Figure 4b , Figure 4a , Figure 4b This invention illustrates a typical embodiment of a fully polarized 360° reflective phase-tunable coded metasurface device for controlling electromagnetic waves in different polarization states. Figure 4a The diagram shows the grouping of varactor diodes 3 on the patch antenna resonant layer. Group A contains varactor diodes 3 in the horizontal direction, which can control the reflection of electromagnetic waves in the x-polarization mode. Group B contains varactor diodes 3 in the vertical direction, which can control the reflection of electromagnetic waves in the y-polarization mode. Figure 4b The diagram illustrates the grouping of the second metallized via group 6 corresponding to each varactor diode 3. The pins of groups A and B are respectively led out to the control terminal via external wiring. It can be seen that the power supplies of groups A and B are not interconnected. In actual operation, the voltages on the two groups of varactor diodes 3 can be set differently according to requirements. Group A can control the reflection of x-polarized electromagnetic waves, and group B can control the reflection of y-polarized electromagnetic waves. Figure 4b The grouping method of the second metallized via group 6 is shown. Group A and Group B correspond to the control voltage of x-polarized and y-polarized electromagnetic waves, respectively. The feeds of Group A and Group B are independent of each other and can be controlled independently.

[0079] Please see Figure 5a , Figure 5b , Figure 5a , Figure 5bThis invention provides a typical embodiment of the relationship between the reflection coefficient of a fully polarized 360° tunable reflection coded metasurface device and the bias voltage on the varactor diode 3. Figure 5a This is a numerical simulation curve showing the change in reflection coefficient as a function of the applied reverse working voltage of a varactor diode when a plane electromagnetic wave with a frequency of 2-5 GHz is perpendicularly incident on a fully polarized 360° tunable reflection coded metasurface device. Figure 5b This is a numerical simulation curve showing the change of the reflection phase with the magnitude of the applied reverse working voltage of the varactor diode. The curve labels indicate the corresponding values ​​of the equivalent capacitance of the varactor diode with respect to the working voltage. In this embodiment, the dielectric substrate material used is a domestically produced PTFE fiberglass cloth copper-clad laminate F4BM from Taizhou Wangling, with a dielectric constant of 2.2, a loss tangent of 0.001, and a copper material thickness of 0.018mm. The selected varactor diode 3 is a Skyworks SMV-1405-040LF model. This diode model is inexpensive and readily available, and has a good parameter adjustment range, demonstrating the general applicability of the structure in this invention. Its adjustable capacitance value depends on the bias voltage range, which is 0V to -25V, corresponding to a capacitance C of 2.6pF to 0.7pF and an equivalent resistance of 0.8Ω. In the simulation, the varactor diode 3 is set as a series model of a variable capacitor and a fixed resistor. In a typical embodiment of this invention, the fixed capacitor element 4 has a capacitance value of 0.5pF. The unit cell period P = 14 mm, and the specific dimensions of the resonant sensitive structure are: L = 8 mm, M = 4 mm, N = 1.5 mm, G = 0.2 mm, D1 = 0.26 mm, D2 = 0.56 mm, d = 1 mm, D = 2 mm. The dimensions of the dielectric substrate are: H1 = 5 mm, H2 = 1 mm. Planar electromagnetic waves with frequencies of 2-5 GHz are perpendicularly incident on a fully polarized 360° reflective tunable coded metasurface device. The reflection amplitude and phase are calculated using CST software. Figure 5a As can be seen from the reflection amplitude, two distinct double-resonance peaks appear in the 3-4 GHz frequency range (corresponding to two resonant cavity frequencies of different sizes), and this resonance changes with the bias voltage of varactor diode 3. With the change in the state of varactor diode 3, the lowest reflection amplitude of the two resonant peaks is greater than -5 dB, while the highest reflection amplitude is greater than -1 dB. From... Figure 5bThe reflection phase curves show a significant phase gradient change within the corresponding resonant frequency range (3~4GHz), and at certain frequencies (e.g., 3.5GHz), it can achieve a continuous variation range of 500°. Overall, within the frequency range where the reflection amplitude remains above -2dB (3.65~3.8GHz), the phase gradient change can achieve 360° full coverage (marked by the gray area). On the other hand, the loss in reflection amplitude is mainly caused by the impedance loss of varactor diode 3, which is unavoidable. Comparing the reflection amplitude curves with C=0.7pF and C=2.6pF, it can be seen that the electromagnetic wave reflection efficiency is higher when the capacitance is smaller. Therefore, in terms of active component selection, choosing diode devices with low resistance and small capacitance is more conducive to achieving high-efficiency designs.

[0080] Figure 6a , Figure 6b This is a typical embodiment of the present invention demonstrating beam control using a 1-bit encoding method for a fully polarized 360° tunable reflection coded metasurface device. The far-field beam pattern of the reflected wave, with a wavelength of 3.8 GHz, is simulated when a plane wave is incident perpendicularly on the fully polarized 360° tunable reflection coded metasurface device. To facilitate control and mitigate the impact of phase abrupt changes between adjacent units, a super subunit (i.e., 4×4 digital encoding units) is constructed. Figure 3a The system consists of four repeating minimum subarrays, each with a consistent control voltage. Two voltages, "0V" and "-9V," are selected using 1-bit encoding to achieve a 180° phase difference. When the varactor diodes in group A are fed, the x-polarized electromagnetic wave beam can be controlled. When group A elements are controlled in a column configuration, alternating "0V" and "-9V" feed voltages on adjacent group A elements achieves a dual-beam splitting effect for x-polarized electromagnetic waves. When group B elements are controlled as single units, alternating "0V" and "-9V" feed voltages on adjacent group B elements achieves a four-beam splitting effect for y-polarized electromagnetic waves. Figure 6a As can be seen, when the feed voltage of group A on two adjacent subarrays is set to alternate between "0V" and "-9V", the dual-beam splitting effect of x-polarized electromagnetic waves can be achieved; when the feed terminal of varactor diode 3 in group B is fed, the beam control effect of y-polarized electromagnetic waves can be achieved. Figure 6b As can be seen, the B group feed voltage on the subarray is set to a checkerboard distribution of "0V" and "-9V", which can achieve the four-beam splitting effect of y-polarized electromagnetic waves.

[0081] Figure 7a , Figure 7bThis is a typical embodiment of the present invention illustrating complex beam control using a hybrid feeding method for a fully polarized 360° tunable reflection phase coded metasurface device. The far-field beam pattern of the reflected wave, with a wavelength of 3.7 GHz, is simulated when a plane wave is incident perpendicularly onto the fully polarized 360° tunable reflection phase coded metasurface device. A super sub-unit (i.e., the smallest sub-array in Figure 3(a)) is constructed using 2×2 digital coding units, with each sub-array having the same control voltage. When the varactor diode 3 in group A is fed, the beam control effect of the x-polarization electromagnetic wave can be achieved. Two voltages, "0V" and "-6V", with 1-bit encoding are selected to achieve a 180° phase difference. The A group of components, with their feed voltages randomly arranged between "0V" and "-6V", achieves diffuse reflection of x-polarized electromagnetic waves. The B group of components, with its feed voltages divided into eight gradients covering 0-360°, achieves a first-order vortex beam effect for y-polarized electromagnetic waves. For example... Figure 7a As shown, by setting the feed voltage of group A components to a random arrangement of "0V" and "-6V", the diffuse reflection effect of x-polarized electromagnetic waves can be achieved. When feeding the varactor diode 3 in group B, the beam control effect of y-polarized electromagnetic waves can be achieved. By selecting eight 3-bit encoded voltages, "0V", "-1V", "-2V", "-3V", "-5V", "-7V", and "-15V", a 45° phase gradient change can be achieved, thus completely covering 360° within the eight voltage ranges. Figure 7b As shown, the feed voltage of the components in group B is set to eight different gradient voltages in different regions, which can achieve the first-order vortex beam effect of y-polarized electromagnetic waves.

[0082] Specifically, for the control of circularly polarized and elliptically polarized electromagnetic waves, the voltages of both ports A and B can be controlled simultaneously, and the spatial distribution of their phases still satisfies the modulation rules of linearly polarized waves. To perform polarization conversion, only the phase difference between the voltages of ports A and B needs to be changed. A phase difference of 90° enables the conversion of circularly polarized waves, a phase difference of 180° enables cross-polarized beam conversion, and other conditions enable different elliptically polarized beam conversions. Therefore, the fully polarized 360° reflective phase-adjustable coded metasurface device implemented using this invention allows for polarization control at any time, achieving beam modulation effects with arbitrary polarization control.

[0083] The above descriptions are merely some examples of specific embodiments of this application. Other complex beam effects can be obtained by adjusting the voltage magnitude and combination at different locations. The technical solutions described in this invention are only some examples of specific embodiments of this application. Other complex beam effects can be obtained by adjusting the voltage magnitude and combination at different locations. Devices with arbitrarily polarized controllable 360° reflection phase full coverage, utilizing similar design principles and structures to achieve this invention, are all within the scope of protection.

[0084] This invention provides a tunable metasurface device with arbitrarily polarized controllable 360° full-coverage reflection phase. Based on an electrically controlled varactor diode, it achieves continuous phase adjustment. The fully polarized 360° tunable reflection phase coded metasurface device provided by this invention employs a dual-resonant structure, which effectively broadens the resonant phase response. It can achieve continuous 360° reflection phase control with full polarization under low loss conditions (within -2dB electromagnetic loss). Furthermore, the controllability of individual digital coding units provides excellent hardware support for achieving comprehensive control of complex beams, and it has broad application prospects in the future field of wireless communication.

[0085] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A resonant sensitive structure, characterized in that, include: A dielectric substrate layer, comprising a top dielectric substrate and a bottom dielectric substrate stacked together; A metal grounding reflective layer is stacked between the top dielectric substrate and the bottom dielectric substrate, and serves as a feed electrode and an electromagnetic wave reflector. A resonant layer is stacked on the underlying dielectric substrate. The resonant layer includes a square metal patch and four pad groups surrounding the square metal patch. The four pad groups correspond to the four sides of the square metal patch and are electrically connected to the square metal patch. Two first metallized via groups penetrate the square metal patch and the top dielectric substrate, and are electrically connected to the square metal patch and the metal ground reflective layer, respectively. The two first metallized via groups are arranged along the x and y directions, respectively, and form an orthogonal resonant cavity separation structure. The minimum distance N between the two first metallized via groups and the edge of the square metal patch is equal. The first metallized via groups have no direct contact with the pad group. The x and y directions are the side length directions of the square metal patch. The two first metallized via groups can respond to horizontally polarized and vertically polarized electromagnetic waves, respectively. The second metallized via group is distributed around the square metal patch. The second metallized via group penetrates the top dielectric substrate and the bottom dielectric substrate. One end of the second metallized via group is electrically connected to the pad group, and the other end extends to the lower surface of the bottom dielectric substrate to form an external power supply port. The second metallized via group is electrically isolated from the metal ground reflective layer.

2. The resonant sensitive structure according to claim 1, characterized in that: The first metallized via group includes a plurality of first metallized vias, and the plurality of first metallized vias included in each first metallized via group are arranged at intervals along the side length direction of the square metal patch.

3. The resonant sensitive structure according to claim 2, characterized in that: The ratio of the minimum distance N between the first metallized via group and the edge of the square metal patch to the side length L of the square metal patch is (0.5~2):(6~10).

4. The resonant sensitive structure according to claim 2, characterized in that: The ratio of the diameter D1 of the first metallized via, the spacing d between adjacent first metallized vias, and the side length L of the square metal patch is (0.2~0.3):(0.5~1.5):(6~10).

5. The resonant sensitive structure according to claim 1, characterized in that: The four pad groups are centrally symmetrically distributed around the square metal patch.

6. The resonant sensitive structure according to claim 5, characterized in that: The pad group includes a plurality of pads arranged at intervals along a direction away from the square metal patch, and the pads are parallel to the square metal patch.

7. The resonant sensitive structure according to claim 6, characterized in that: The ratio of the length M of the pad to the side length L of the square metal patch is (2~4):(6~10).

8. The resonant sensitive structure according to claim 1, characterized in that: The second metallized via group includes four second metallized vias, each of which corresponds to one of the pad groups.

9. The resonant sensitive structure according to claim 8, characterized in that: The diameter D2 of the second metallized via is smaller than the width of the pad.

10. The resonant sensitive structure according to claim 8, characterized in that: Each of the second metallized vias is located in the geometric center region of one of the pad groups.

11. The resonant sensitive structure according to claim 1, characterized in that: The resonant sensitive structure is generally square, and the side length of the square metal patch is less than or equal to the period length P of the resonant sensitive structure.

12. The resonant sensitive structure according to claim 11, characterized in that: The ratio of the period length P of the resonant sensitive structure to the side length L of the square metal patch is (10~20):(6~10).

13. The resonant sensitive structure according to claim 1, characterized in that: The resonant layer has a centrosymmetric structure.

14. The resonant sensitive structure according to claim 1 or 13, characterized in that: The resonant sensitive structure is a mirror-symmetric structure. The axis of symmetry of the resonant sensitive structure coincides with one diagonal of the square metal patch and passes through the orthogonal intersection of the two first metallized via groups.

15. A fully polarized 360° reflective phase-tunable coded metasurface device, comprising a plurality of digital coding units periodically arranged and sequentially electrically connected in the x and y directions, characterized in that: The digital encoding unit includes the resonant sensitive structure according to any one of claims 1-14, and four varactor active devices, which are respectively disposed on the four pad groups. Each varactor active device is electrically connected to the square metal patch and a pad group. Each digital encoding unit can be individually controlled by a bias voltage applied to the varactor active device and can switch between different operating states. A first resonant cavity or a second resonant cavity is formed between the two resonant cavity separation structures of two adjacent digital encoding units. The first resonant cavity and the second resonant cavity have different sizes.

16. The fully polarized 360° tunable reflection phase coded metasurface device according to claim 15, characterized in that: The digital encoding unit also includes four fixed capacitor elements, and the four fixed capacitor element groups are respectively arranged on the four pad groups. Each fixed capacitor element is connected in series with a varactor active device.

17. The fully polarized 360° tunable reflection phase coded metasurface device according to claim 16, characterized in that: A second fixed capacitor element and a varactor active device electrically connected to one of the pad groups are located on both sides of a second metallized via connected to the pad group.

18. The fully polarized 360° tunable reflection phase coded metasurface device according to claim 17, characterized in that: The varactor active device includes a varactor diode.

19. The fully polarized 360° tunable reflection phase coded metasurface device according to claim 15, 16, 17, or 18, characterized in that: Multiple digital encoding units are combined into multiple subarrays, each subarray comprising 2×2 digital encoding units arranged in a mirror configuration, and each subarray having a centrally symmetric structure.

20. A method for achieving fully polarized 360° adjustable reflection phase, characterized in that, include: Provides a fully polarized 360° reflective phase-tunable coded metasurface device as described in any one of claims 15-19, wherein a bias voltage is independently applied to a plurality of varactor active devices in each of the digital coding units.

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