Resonance sensitive structure, full-polarization 360-degree reflection phase adjustable coding metasurface device and application thereof

Abstract

The invention discloses a resonance sensitive structure, a full-polarization 360-degree reflection phase-adjustable coding metasurface device and application of the full-polarization 360-degree reflection phase-adjustable coding metasurface device. According to the fully-polarized 360-degree reflection phase-adjustable coding metasurface device, the continuous adjustable effect of the phase is realized based on the electrically-controlled variable capacitance diode, the resonant phase response can be effectively expanded by adopting a double-resonant structure, and the full-polarized 360-degree reflection phase-adjustable coding metasurface device can be used in the case of low loss (within-2dB electromagnetic loss), so that the full-polarized 360-degree reflection phase-adjustable coding metasurface device has a wide application prospect. And complete polarization 360-degree reflection phase continuous regulation and control can be realized. Besides, due to the controllability of a single unit, good hardware support is provided for achieving the comprehensive control effect of complex beams, and the wide application prospect is achieved in the future wireless communication field.

Description

Technical Field

[0001] The present invention particularly relates to a resonant sensitive structure, a coding metasurface device with all-polarization 360° reflection phase tunable, and a method for using the same, belonging to the field of electromagnetic metamaterials. Background Art

[0002] Electromagnetic metamaterials are artificial composite materials composed of periodic or quasi-periodic units with extraordinary physical properties. By adjusting the size, shape, and spatial distribution characteristics of the unit structure, the electromagnetic parameters of the material can be precisely controlled, thereby effectively manipulating the radiation, scattering, and propagation behaviors of spatial electromagnetic waves. Phase control of electromagnetic waves on the surface is of great significance in both basic 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, reflector antennas, beamforming and beam scanning antennas, phase shifters, etc. In most of these applications, full-phase control in the range of 360° is usually required.

[0003] Passive metasurfaces usually achieve phase control by changing the size of metal resonators. For reflective metasurfaces, by adding an additional 180° reflection phase mutation provided by a perfect electric conductor surface (PEC), an overall tuning effect of 360° phase can be relatively easily achieved. However, once a passive metasurface is manufactured, its characteristics are fixed. Tunable elements include temperature-tunable phase change materials, electrically tunable graphene, and active microwave components (such as PIN diodes and varactor diodes), mechanical tuning, etc., depending on the operating frequency and scenario.

[0004] In the microwave band, PIN diodes and varactor diodes are often used as electrically tunable devices to regulate electromagnetic responses. Currently, tunable metasurface devices have been widely studied. However, due to limitations such as the parameter range of commercially available diode devices, the vast majority of designs cannot effectively meet the continuous tunability of 360° full phase (most can only achieve phase control of about 340°). Even if it can be achieved, problems such as large reflection loss or single polarization (such as one or several linear polarizations or circular polarizations) are faced. There are few device structures that can meet the requirements of low loss, support all-polarization and arbitrary polarization, and achieve continuous dynamic regulation of 360° reflection phase. Therefore, as a scarce technology with high flexibility, it is highly necessary to further explore its design and optimization methods.

[0005] The tunability of active metasurfaces usually depends on the controllable parameter range of the selected tunable elements and the structural response of the metasurface metal resonators. The combination of the two should be able to maximize the tuning range of the phase parameters.

[0006] At present, in the microwave band, PIN diodes and varactor diodes are often used as electrically tunable devices to regulate electromagnetic responses. However, most of the existing unit structures cannot effectively achieve full coverage of 360° phase. Even if it can be achieved, there are still problems such as large reflection loss or single polarization. There are few device structures that can support full polarization, arbitrary polarization, and 360° reflection phase dynamic regulation under low loss conditions. Summary of the Invention

[0007] The main object of the present invention is to provide a resonance-sensitive structure, a coding metasurface device with full-polarization 360° reflection phase tunability and its application, which can achieve continuous phase regulation effect under low loss conditions (within -2dB electromagnetic loss), provide good hardware support for real-time controllability of complex beams, and thus overcome the deficiencies in the prior art.

[0008] To achieve the foregoing invention object, the technical solutions adopted by the present invention include:

[0009] In the first aspect of the embodiment of the present invention, a resonance-sensitive structure is provided, which includes:

[0010] A dielectric substrate layer, which includes a top dielectric substrate and a bottom dielectric substrate stacked;

[0011] A metal ground reflection layer, which is stacked between the top dielectric substrate and the bottom dielectric substrate and serves as a feeding electrode and an electromagnetic wave reflector;

[0012] A resonance layer, which is stacked on the bottom dielectric substrate. The resonance layer includes a square metal patch and four pad groups surrounding the square metal patch. The four pad groups respectively 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, which penetrate the square metal patch and the top dielectric substrate and are respectively electrically connected to the square metal patch and the metal ground reflection layer. The two first metallized via groups are arranged along the x direction and the y direction respectively to form an orthogonal resonance 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 groups. The x direction and the y direction are the side length directions of the square metal patch. The two first metallized via groups can respectively respond to two types of electromagnetic waves, namely horizontal polarization and vertical polarization.

[0014] The second metallized via group is distributed around the square metal patch. The second metallized via group penetrates through 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 feeding port. The second metallized via group is electrically isolated from the metal ground reflection layer.

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

[0016] Further, 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] Further, the ratio of the diameter D1 of the first metallized via, the distance 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] Further, the four pad groups are symmetrically distributed around the square metal patch in a central symmetry manner.

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

[0020] Further, 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] Further, the second metallized via group includes four second metallized vias. Each second metallized via corresponds to one pad group.

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

[0023] Further, each second metal via is located in the geometric center region of one pad group.

[0024] Further, the overall resonant sensitive structure is a square structure. The side length of the square metal patch is less than or equal to the period length P of the resonant sensitive structure.

[0025] Further, 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 overall resonant sensitive structure has a mirror-symmetric structure. The symmetry axis of the resonant sensitive structure coincides with a diagonal of the square metal patch and passes through the orthogonal intersection point of the two first metallized via groups.

[0028] In the second aspect of the embodiments of the present invention, a fully polarized 360° reflection phase tunable coded metasurface device is provided, which includes a plurality of digital coding units arranged periodically in the x and y directions and electrically connected in sequence;

[0029] The digital coding unit includes the above-mentioned resonant sensitive structure, and four varactor active devices. The four varactor active devices are respectively arranged on the four pad groups in one-to-one correspondence. Each varactor active device is electrically connected to the square metal patch and one pad group. Each digital coding unit can be independently controlled by the bias voltage applied to the varactor active device and switched between different working states. A first resonant cavity or a second resonant cavity is formed between the two resonant cavity separation structures of two adjacent digital coding units, and the sizes of the first resonant cavity and the second resonant cavity are different.

[0030] Furthermore, the digital coding unit further includes four fixed capacitor elements. The four fixed capacitor element groups are respectively arranged on the four pad groups in one-to-one correspondence, 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 pad group 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, a plurality of the digital coding units are combined into a plurality of sub-arrays. The sub-array includes 2×2 digital coding units arranged in a mirror image, and each sub-array has a centrosymmetric structure.

[0034] In the third aspect of the embodiments of the present invention, a method for realizing fully polarized 360° reflection phase tunability is provided, which includes: providing the fully polarized 360° reflection phase tunable coded metasurface device, and independently applying a bias voltage to the multiple varactor active devices of each digital coding unit.

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

[0036] Step 1: Use printed circuit board technology (PCB) to form an axially symmetric and centrosymmetric patch-type metal resonant structure (i.e., the resonant sensitive structure) on a commercial dielectric substrate to constitute a 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 constituting a dual-resonator structure; these metallized vias can act on the electromagnetic response of vertically polarized beams through horizontal arrangement and act on the electromagnetic response of horizontally polarized beams through longitudinal arrangement.

[0038] Step 3: Solder components such as varactor diodes at the pad positions of the patch-type metal resonant structure of the metasurface to realize an electrically tunable capacitor.

[0039] Step 4: Lead out the feeding part of the metasurface from the metallized vias on the back with leads and connect it to the control platform to achieve the effect of controllability of a single unit.

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

[0041] The tunable metasurface device with 360° reflection phase full coverage and arbitrary polarization controllability provided by the present invention adopts a dual-resonant structure to broaden the bandwidth, realizes continuous phase tunability based on an electrically controlled varactor diode, and can achieve continuous phase control of all polarizations under low loss (within -2dB electromagnetic loss).

[0042] The tunable metasurface device with 360° reflection phase full coverage and arbitrary polarization controllability provided by the present invention can effectively control all polarizations, and each digital coding unit can be individually controlled. By arbitrarily arranging and combining unit sub-arrays and feeding in different regions, the real-time controllability of complex beams can be effectively achieved, and it has broad application prospects in the future wireless communication field. Description of the Drawings

[0043] Figure 1 is a schematic diagram of the beam control effect of a coded metasurface device with full polarization 360° reflection phase tunability provided in a typical embodiment of the present invention;

[0044] Figure 2a is a perspective view of the digital coding unit of a coded metasurface device with full polarization 360° reflection phase tunability provided in a typical embodiment of the present invention;

[0045] Figure 2b 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 2cIt is a schematic diagram of the metal ground plane structure of the metal ground reflection layer with the digital coding unit in the middle in a typical embodiment of the present invention;

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

[0048] Figure 3a It is a schematic diagram of the arrangement structure of the minimum unit sub-array in a full-polarization 360° reflection phase-tunable coded metasurface device provided in a typical embodiment of the present invention;

[0049] Figure 3b It is a schematic diagram of the array arrangement structure of a full-polarization 360° reflection phase-tunable coded metasurface device provided in a typical embodiment of the present invention;

[0050] Figure 3c It is a schematic diagram of the structures of two different-sized resonant cavities formed by the first metallized via group and the metals on both sides of the substrate dielectric substrate layer in a full-polarization 360° reflection phase-tunable coded metasurface device provided in a typical embodiment of the present invention;

[0051] Figure 3d It is a perspective view of the array arrangement of a full-polarization 360° reflection phase-tunable coded metasurface device provided in a typical embodiment of the present invention;

[0052] Figure 4a 、 Figure 4b It is a schematic diagram of the feeding control grouping method for different polarization states of a full-polarization 360° reflection phase-tunable coded metasurface device provided in a typical embodiment of the present invention;

[0053] Figure 5a 、 Figure 5b They are respectively the numerical simulation curves of the reflection coefficient and the reflection phase varying with the magnitude of the reverse operating voltage applied to the varactor diode when a plane electromagnetic wave with a frequency of 2 - 5 GHz is vertically incident on a full-polarization 360° reflection phase-tunable coded metasurface device in a typical embodiment of the present invention;

[0054] Figure 6a 、 Figure 6b It is a case of realizing beam control by 1-bit coding method in a typical embodiment of the present invention;

[0055] Figure 7a 、 Figure 7b It is a case of realizing beam control by multi-bit hybrid coding method in a typical embodiment of the present invention. Specific implementation manner

[0056] In view of the deficiencies in the prior art, through long-term research and a large number of practices, the inventors of this case were able to propose the technical solution of the present invention. The following will further explain the technical solution, its implementation process and principle, etc. in combination with the drawings and specific implementation cases.

[0057] Active metamaterials break through the limitation of the fixed electromagnetic functions of traditional passive metamaterials, and can achieve purposes such as canceling dielectric losses, regulating the intensity of electromagnetic resonance response, and broadening the working bandwidth, greatly expanding the applicable range of metamaterials. The tunability of an active metasurface usually depends on the controllable parameter range of the selected tunable elements and the loop response of the metasurface metal resonator. The combination of the two should be able to maximize the tuning range of the phase parameter. In the microwave band, PIN diodes and varactor diodes are often used as electrically tunable devices to regulate the electromagnetic response. However, most of the unit structures that have been studied so far cannot meet the full coverage of 360° phase. Even if it can be achieved, it is inevitable to be accompanied by large reflection losses, or only the tunability of a single polarization (such as a certain linear polarization or circular polarization) wave can be achieved, etc. There are few device structures that can support full polarization, arbitrary polarization, and continuous dynamic regulation of 360° reflection phase under low-loss conditions.

[0058] The present invention aims to increase the phase tunability range of a reflective metasurface and reduce the reflection loss, and proposes a tunable control method with full coverage of 360° reflection phase controllable for any polarization. The proposed active metasurface broadens the bandwidth by adopting a multi-resonant structure and realizes the continuous tunable effect of the phase based on an electrically controlled varactor diode. It can achieve continuous phase regulation of full polarization under low-loss conditions (within -2dB electromagnetic loss), providing good hardware support for realizing the real-time controllable effect of complex beams. It has broad application prospects in the future wireless communication field.

[0059] An encoded metasurface device with full polarization and 360° reflection phase tunable provided by an embodiment of the present invention adopts a multi-cavity resonant structure to broaden the bandwidth and realizes the continuous tunable effect of the phase based on an electrically controlled varactor diode. This device has excellent electrical regulation performance, can effectively broaden the phase regulation range of the reflective metasurface, and achieve low reflection loss. Correspondingly, a control method for the encoded metasurface with full coverage of 360° reflection phase controllable for any polarization is proposed, which can achieve continuous phase regulation of narrowband full polarization for a single unit under low-loss conditions (within -2dB electromagnetic loss). It supports independent control of different polarization electromagnetic waves to achieve diversified functions and provides good hardware support for the real-time controllable effect of complex beams. It has broad application prospects in the future wireless communication field.

[0060] In a more specific implementation, please refer to Figure 1, A fully polarized 360° reflection phase tunable coded metasurface device, comprising a metal resonant array formed by a plurality of periodically arranged resonant sensitive structures with the same size, on which active devices such as varactor diodes are welded. Each resonant sensitive structure and a group of active devices such as varactor diodes form a digital coding unit. A plurality of digital coding units are closely connected in the x-direction and y-direction with a distance of zero, and each digital coding unit can be individually controlled by an externally applied bias voltage to achieve switching between different working states.

[0061] In the present invention, active devices such as varactor diodes, as dynamic regulation components, can effectively achieve low-loss reflection in a narrow band range and continuous variation control of 360° reflection phase. Under the control of an FPGA, digital coding units at different positions can be given different bias voltages, so as to achieve different electromagnetic resonance responses. Through such a design, when electromagnetic waves within the working wavelength range are normally incident on the coded metasurface device, the reflected electromagnetic waves can be effectively controlled, thereby generating effects such as split beam, random scattering, vortex beam, etc.

[0062] Please refer to Figures 2a - 2d , Figures 2a - 2d shows the minimum structural unit - digital coding unit of a fully polarized 360° reflection phase tunable coded metasurface device. The 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 reflection layer 9, a patch antenna resonant layer (i.e., the aforementioned resonant layer, which can also be called a metal resonant layer, the same below), 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 in the z-direction. The metal ground reflection layer 9 is stacked in the z-direction between the top dielectric substrate 7 and the bottom dielectric substrate 8. The metal ground reflection layer 9 is used to act as a feeding electrode and a reflector.

[0065] The patch antenna resonant layer is stacked in 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 through 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 reflection layer 9 respectively. The two first metallized via groups 5 are arranged along the x direction and the 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 through 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 feeding port. The second metallized via group 6 is electrically isolated from the metal ground reflection layer 9. Four electro-tuning device groups are respectively arranged 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 direction, the y direction, and the z direction respectively correspond to the x-axis direction, the y-axis direction, and the z-axis direction of the three-dimensional coordinate system. The side length direction of the square metal patch 1 is parallel to the x direction and the y direction. It can also be understood that the x direction and the y direction are the side length directions of the square metal patch 1.

[0068] Specifically, the material of the dielectric substrate layer can be various chemically stable plastic punching materials. Specifically, the material of the dielectric substrate layer can be a domestic commercial dielectric substrate material with a relatively high cost performance. Exemplarily, the material of the dielectric substrate layer can be a polytetrafluoroethylene fiberglass cloth clad copper plate 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 resonant layer of the patch antenna is shown. Four pad groups 2 correspond to the four sides of the square metal patch 1 respectively and are centrosymmetrically distributed / axially symmetrically distributed. The symmetry axis is the two median lines / diagonals of the square metal patch 1. Each pad group 2 includes a plurality of metal pads arranged at intervals in the x direction or the y direction. The metal pads are closely connected to the square metal patch 1. One side of the metal pad and the square metal patch 1 connected thereto 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 electrically tunable 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 at intervals in the direction away from the square metal patch 1 in sequence. The varactor diode 3 is electrically connected to the square metal patch 1 and the metal pad respectively. The fixed capacitor element 4 is connected in series with the varactor diode 3 through the metal pad. Specifically, the varactor diode 3 is used to change the capacitance parameter, thereby mainly changing the resonant response on the patch antenna. The adjustable effect is better in the resonant sensitive range, and the phase control range is wider. However, generally speaking, the basic capacitance value of the varactor diode devices easily available on the market is relatively large (usually between 1 and 10 pF), slightly larger than the resonant control range of the metasurface unit (i.e., the resonant sensitive structure) in the present invention (the resonant response of the metasurface unit of the present invention at the working frequency band is sensitive to a capacitance of about 1 pF). By adopting the method of connecting the fixed capacitor element 4 in series, the overall capacitance value can be effectively reduced, so that it is within the sensitive range, thereby effectively controlling the resonant frequency and realizing wide-range phase control. Specifically, the four groups of electrically tunable device groups are also centrosymmetrically distributed around the square metal patch 1.

[0070] Specifically, the second metallization via group 6 includes four second metal vias. The four second metal vias correspond to the four pad groups 2 one by one. Each second metallization via is located at the geometric center of a pad group 2. Each second metallization via is correspondingly arranged between a varactor diode 3 and a fixed capacitor 4 on the pad group 2 where it is located. This position has a relatively small influence on the resonant circuit and is used to connect out from the back of the bottom dielectric substrate 8 to provide a voltage bias for the diode. It should be noted that although the second metallization via group 6 penetrates the metal ground reflection layer 9, it is electrically isolated from the metal ground reflection layer 9. Figure 2c The specific morphology of the metal ground reflection layer 9 is shown. It can be clearly seen that the first metallization via group 5 is directly connected to the metal ground reflection layer 9, while the second metallization via group 6 is not in contact with the metal ground reflection layer 9 through the opening 10 on the metal ground reflection layer 9. The first metallization via group 5 and the second metallization via group 6 are respectively connected to the positive and negative poles of the varactor diode 3. Figure 2dThe specific topography of the underlying dielectric substrate 8 is shown. It can be seen that only the second metallized via group 6 penetrates the underlying dielectric substrate 8 and needs to be led out by leads. Since the four outgoing ports of the second metallized via group 6 are not connected to each other, independent feeding can be achieved, thereby realizing the control and conversion of electromagnetic waves in different polarization modes.

[0071] Specifically, the first metallized via group 5 includes a plurality of first metallized vias. The plurality of first metallized vias included in the two first metallized via groups are sequentially arranged at intervals along the x-direction and the y-direction 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 vertically intersect to form an orthogonal resonant cavity separation structure. The resonant cavity separation structure divides the patch antenna resonator (i.e., the resonant sensitive structure) into two parts and forms two resonant cavities of different sizes with the adjacent resonant sensitive structures (i.e., the first and second resonant cavities described in the claims), thereby broadening the bandwidth. At the same time, through two arrangement methods in the transverse direction (i.e., the x-direction, the same below) and the longitudinal direction (i.e., the vertical direction, the y-direction, the same below), the two types of electromagnetic waves in the vertical polarization and the horizontal polarization can be affected respectively. It should be particularly noted that the two first metallized via groups 5 are all distributed within the orthographic projection area of the square metal patch 1, and the first metallized via group 5 cannot penetrate the metal pad to prevent short circuits and effectively realize the division of the resonant cavity; in addition, the pad group 2 is completely located on one side of the extension plane / line of the first metallized via group 5 along the x-direction and the y-direction, that is, the two pad groups arranged oppositely along the x-direction / y-direction are completely 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 distance 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). The diameter D2 of the second metal via is smaller than the width of the metal pad.

[0073] Specifically, the thickness of the patch antenna resonant layer is 0.018 mm or 0.036 mm. Specifically, the material of the patch antenna resonant layer is a good conductor material, generally made of copper, and gold can be plated on it to increase the performance stability, not easily corroded and oxidized, and the device has a long service life.

[0074] Specifically, the structures and dimensional parameters of the digital coding units are the same, except for the bias voltage magnitudes on the varactor diodes, so as to control the electromagnetic responses of each digital coding unit. Specifically, the varactor diode 3 should have a suitable capacitance adjustable range (usually adjustable on the order of 1 pF, and a suitable regulation range needs to be selected according to the diodes on the market), so as to effectively change the circuit resonance characteristics and form a phase change.

[0075] Specifically, the working band corresponding to the structural parameters of the fully polarized 360° reflection phase adjustable coding metasurface device is the microwave band, and the working band can be adjusted according to the selection of the structural parameters. Specifically, the sizes of the resonance sensitive structures are all less than or equal to the unit period P of the digital coding unit. For different wavelengths, by changing the unit period P of the digital coding unit and the sizes of the resonance sensitive structures, good reflectivity and phase control effects can be obtained. In a relatively typical implementation case, please refer to Figures 2a - 2d again, the unit period P of the digital coding unit is 10 mm to 20 mm, the side length L of the square metal patch 1 is 6 mm to 10 mm, the width / length M of the metal pad is 2 mm to 4 mm, the gap G between the metal pads is generally determined by the pin pitch of the components, the gap G between the metal pads is 0.1 mm to 0.3 mm, the diameter D1 of the first metallized via is 0.2 mm to 0.3 mm, and the interval d between adjacent first metallized vias is 0.5 mm to 1.5 mm. The first metallized via group 5 includes two arrangements of horizontal and vertical, and the minimum distance N from its edge to the square metal patch 1 is the same, N = 0.5 mm to 2 mm. The second metallized via group 6 generally needs to be able to connect to an external lead and cannot exceed the size of the metal pad. Therefore, the diameter D2 of the second metallized via is 0.4 mm to 0.7 mm. The diameter D of the opening 10 on the metal ground reflection layer 9 needs to be greater than the diameter of the second metallized via to avoid short circuit, but cannot be too large to affect the reflection performance. The diameter D of the opening 10 on the metal ground reflection layer 9 is 1 mm to 3 mm. According to this set of optimized parameters, the working frequency band can be effectively adjusted, and the structure can achieve advantages such as good phase controllability and high reflection efficiency.

[0076] Specifically, please refer to Figures 3a - 3d again, a fully polarized 360° reflection phase adjustable coding metasurface device provided by an embodiment of the present invention includes a plurality of digital coding units arranged in an array. Specifically, the plurality of digital coding units are combined into a plurality of sub-arrays. Figure 3a shows the arrangement structure of the smallest unit of the sub-array. The sub-array is formed by mirror arranging 2×2 structures with the same structure and size of the digital coding units, and has the characteristic of central symmetry. Figure 3bShows the overall array structure formed by the repeated arrangement of multiple sub-array periods. The number of sub-arrays depends on the actual requirements, and the overall size is generally 3 to 5 working wavelengths.

[0077] Figure 3c Shows the distribution of two different-sized resonant cavities formed by the first metallized via group 5 and the metal surfaces on both sides of the dielectric substrate layer (the surfaces of the patch antenna 1, the pad 2, and the metal ground reflection layer 9). The two different-sized resonant cavities correspond to different resonant frequencies respectively. The superposition of these two resonant frequencies can effectively broaden the bandwidth and obtain a large phase control effect. Figure 3d Shows a perspective view of the corresponding resonant cavity. It can be clearly seen that the first metallized via group 5 and the metal surfaces on both sides of the dielectric substrate layer together form two cavities of different sizes. Among them, the pad group 2 on the top layer and the varactor diode 3, as effective components participating in resonance, play a key role in controlling the phase. Therefore, by changing the state of the varactor diode 3, the resonance of the resonant cavity can be affected. In addition, electromagnetic waves in horizontal polarization (x-polarization) and vertical polarization (y-polarization) modes respectively correspond to the resonant cavities in the horizontal and vertical directions, so that it can effectively control different polarization waves in a broadband manner.

[0078] Please refer to Figure 4a 、 Figure 4b , Figure 4a 、 Figure 4b Shows the control method of a full-polarization 360° reflection phase-tunable coding metasurface device provided by a typical embodiment of the present invention for electromagnetic waves in different polarization states. Figure 4a Shows the grouping situation of the varactor diodes 3 on the patch antenna resonance layer. Group A includes the varactor diodes 3 in the horizontal direction, which can control the reflection of electromagnetic waves in the x-polarization mode. Group B includes the varactor diodes 3 in the vertical direction, which can control the reflection of electromagnetic waves in the y-polarization mode. Figure 4b Shows the grouping method of the second metallized via group 6 corresponding to each varactor diode 3. The pins of Group A and Group B are respectively led out through external wiring and connected to the control terminal. It can be seen that the power supplies of Group A and Group B are not connected to each other. In the actual operation process, the voltages on the two groups of varactor diodes 3 can be set differently according to the requirements. Group A can control the reflection of electromagnetic waves in the x-polarization mode, and Group B can control the reflection of electromagnetic waves in the y-polarization mode. Figure 4b Shows the grouping method of the second metallized via group 6. Group A and Group B respectively correspond to the control voltages of x-polarized and y-polarized electromagnetic waves. The power supplies of Group A and Group B are not related to each other and can be independently controlled.

[0079] Please refer to Figure 5a 、 Figure 5b , Figure 5a 、 Figure 5bThe corresponding relationship between the reflection coefficient of a fully polarized 360° reflection phase tunable coded metasurface device provided by a typical embodiment of the present invention and the bias voltage on the varactor diode 3 Figure 5a is a numerical simulation curve of the reflection coefficient varying with the magnitude of the reverse operating voltage applied to the varactor diode when a plane electromagnetic wave with a frequency of 2 - 5 GHz is vertically incident on a fully polarized 360° reflection phase tunable coded metasurface device in a typical embodiment of the present invention. Figure 5b is a numerical simulation curve of the reflection phase varying with the magnitude of the reverse operating voltage applied to the varactor diode. The curve annotation shows the corresponding values of the equivalent capacitance of the varactor diode with the operating voltage. In this embodiment, the material of the dielectric substrate layer is the polytetrafluoroethylene fiberglass cloth copper clad laminate F4BM from Taizhou Wangling, China, with a dielectric constant of 2.2, a loss tangent of 0.001, and a copper material thickness of 0.018 mm. The selected varactor diode 3 model is SMV - 1405 - 040LF from Skyworks. This diode model is inexpensive and easily available, and has a good parameter adjustment range, demonstrating the general applicability of the structure in the present invention. Its adjustable capacitance value depends on the bias voltage variation range, with a bias voltage of 0 V to - 25 V, corresponding to a capacitance C = 2.6 pF to 0.7 pF, and an equivalent resistance of 0.8 Ω. In the simulation, the varactor diode 3 is set as a series model of a variable capacitor and a fixed resistor. The capacitance value of the fixed capacitor element 4 selected in a typical embodiment of the present invention is 0.5 pF. The unit period P = 14 mm, and the specific size parameters of the resonance - 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 size of the dielectric substrate layer is: H1 = 5 mm, H2 = 1 mm. When a plane electromagnetic wave with a frequency of 2 - 5 GHz is vertically incident on a fully polarized 360° reflection phase tunable coded metasurface device, the reflection amplitude and phase are simulated and calculated using CST software. From Figure 5a the reflection amplitude, it can be seen that there are two obvious double - resonance peaks (corresponding to two resonance cavity frequencies with different magnitudes) in the frequency range of 3 - 4 GHz, and this resonance changes with the bias voltage of the varactor diode 3. As the state of the varactor diode 3 changes, the lowest reflection amplitude of the two resonance peaks is greater than - 5 dB, and the highest reflection amplitude is greater than - 1 dB. From Figure 5bFrom the reflection phase curve, it can be seen that within the corresponding resonant frequency range (3 - 4 GHz), there is a large phase gradient change. And at some frequency points (such as 3.5 GHz), a continuous change range of 500° can be achieved. Generally speaking, within the frequency range where the reflection amplitude remains above -2 dB (3.65 - 3.8 GHz), its phase gradient change can achieve a full coverage of 360° (the range marked in the gray area). On the other hand, the loss of the reflection amplitude is mainly caused by the impedance loss of the varactor diode 3, which is inevitable. By comparing the reflection amplitude curves when C = 0.7 pF and C = 2.6 pF, it can be seen that when the capacitance is smaller, the reflection efficiency of electromagnetic waves is higher. Therefore, in the selection of active components, it is better to choose diode devices with low resistance and small capacitance, which is more conducive to achieving a high-efficiency design.

[0080] Figure 6a 、 Figure 6b This is a case where a full-polarization 360° reflection phase-tunable coded metasurface device in a typical embodiment of the present invention uses a 1-bit coding method to achieve beam control. The far-field beam situation of the reflected wave when a plane wave is vertically incident on the full-polarization 360° reflection phase-tunable coded metasurface device is simulated and calculated, and the wavelength is set to 3.8 GHz. For the convenience of control and to reduce the influence of phase mutations between adjacent units, 4×4 digital coding units are used to construct a super subunit (i.e., Figure 3a the 4 repeated minimum sub-arrays in Figure 6a ), and the control voltage of each sub-array is the same. Two voltages of "0V" and "-9V" for 1-bit coding are selected to achieve a phase difference of 180°. When feeding the feeding end of the varactor diode 3 in group A, the control effect of the electromagnetic wave beam in the x-polarization mode can be achieved. When controlling the components in group A in a columnar manner, the feeding voltages of the components in group A of adjacent sub-arrays are set alternately as "0V" and "-9V", and the double-beam splitting effect of the electromagnetic wave in the x-polarization mode can be achieved; when controlling the components in group B in a single-unit manner, the feeding voltages of the components in group B of adjacent sub-arrays are set alternately as "0V" and "-9V", and the four-beam splitting effect of the y-polarized electromagnetic wave can be achieved. As Figure 6b can be seen, when the feeding voltages of group A on adjacent two columns of sub-arrays are set alternately as "0V" and "-9V", the double-beam splitting effect of the x-polarized electromagnetic wave can be achieved; when feeding the feeding end of the varactor diode 3 in group B, the control effect of the electromagnetic wave beam in the y-polarization mode can be achieved. As Figure 6b can be seen, when the feeding voltages of group B on the sub-array are set in a checkerboard interval distribution of "0V" and "-9V", the four-beam splitting effect of the y-polarized electromagnetic wave can be achieved.

[0081] Figure 7a 、 Figure 7bThis is a case of complex beam control achieved by a hybrid feeding method for a fully polarized 360° reflection phase - tunable coded metasurface device in a typical embodiment of the present invention. The far - field beam situation of the reflected wave when a plane wave is vertically incident on the fully polarized 360° reflection phase - tunable coded metasurface device is simulated and calculated, and the wavelength is set to 3.7 GHz. A super - subunit (i.e., the smallest sub - array in Fig. 3(a)) is constructed by using 2×2 digital coding units, and the control voltage of each sub - array is the same. When feeding the feeding ends of the varactor diodes 3 in group A, the control effect of the electromagnetic wave beam in the x - polarization mode can be achieved. Two voltages of 1 - bit coding, "0V" and "-6V", are selected to achieve a 180° phase difference. The feeding voltages of the components in group A are set as a random arrangement of "0V" and "-6V", and the diffuse reflection effect of the x - polarized electromagnetic wave can be achieved; the feeding voltages of the components in group B are set as 8 gradient voltages in different regions, forming a voltage gradient coverage of 0 - 360°, and the first - order vortex beam effect of the y - polarized electromagnetic wave can be achieved. As Figure 7a shown, the feeding voltages of the components in group A are set as a random arrangement of "0V" and "-6V", and the diffuse reflection effect of the x - polarized electromagnetic wave can be achieved. When feeding the feeding ends of the varactor diodes 3 in group B, the control effect of the y - polarized electromagnetic wave beam can be achieved. Eight voltages of 3 - bit coding, "0V", "-1V", "-2V", "-3V", "-5V", "-7V" and "-15V", are selected, and a 45° phase gradient change can be achieved, so that it can completely cover 360° within the range of 8 voltages. As Figure 7b shown, the feeding voltages of the components in group B are set as 8 gradient voltages in different regions, and the first - order vortex beam effect of the y - polarized electromagnetic wave can be achieved.

[0082] Specifically, for the control of circularly polarized and elliptically polarized electromagnetic waves, the voltages of ports A and B can be controlled simultaneously, and the spatial distribution of the phase still satisfies the regulation law of the linearly polarized wave. If polarization conversion is to be carried out, only the phase difference corresponding to the voltages of ports A and B needs to be changed. Among them, a phase difference of 90° can achieve the conversion of circularly polarized waves, a phase difference of 180° can achieve the conversion of cross - polarized beams, and in other cases, different elliptically polarized beam conversions can be achieved. Therefore, the fully polarized 360° reflection phase - tunable coded metasurface device implemented by the present invention can control polarization at any time and obtain an arbitrarily polarization - controllable beam modulation effect.

[0083] The above are only some cases of the specific implementation manners of this application. For other complex beam effects, they can be obtained by adjusting the voltage magnitudes and combination manners at different positions by oneself. What is described in the technical solution of the present invention are only some cases of the specific implementation manners of this application. For other complex beam effects, they can be obtained by adjusting the voltage magnitudes and combination manners at different positions by oneself. Devices that utilize similar design principles and structures as the present invention to achieve full coverage of 360° reflection phase with arbitrary polarization controllability are all within the protection scope.

[0084] The tunable metasurface device with full coverage of 360° reflection phase with arbitrary polarization controllability provided by the present invention realizes the continuous adjustable effect of the phase based on an electrically controlled varactor diode. The full-polarization 360° reflection phase tunable coded metasurface device provided by the present invention adopts a double-resonant structure, which can effectively broaden the resonant phase response and can achieve continuous control of the full-polarization 360° reflection phase under the condition of low loss (within -2dB electromagnetic loss). In addition, due to the controllability of a single digital coding unit, it also provides good hardware support for realizing the comprehensive control effect of complex beams and has broad application prospects in the future wireless communication field.

[0085] It should be understood that the above embodiments are only used to illustrate the technical concept and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope 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 in layers; A metal ground reflection layer, which is stacked between the top dielectric substrate and the bottom dielectric substrate and serves as a feeding electrode and an electromagnetic wave reflector; A resonance layer is stacked on the bottom dielectric substrate, the resonance layer includes a square metal patch and four pad groups surrounding the square metal patch, the four pad groups respectively correspond to the four sides of the square metal patch and are electrically connected to the square metal patch, Two first metallized via groups, the 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 direction and the y direction 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 group has no direct contact with the pad group, the x direction and the y direction are the length directions of the side of the square metal patch, and the two first metallized via groups can respectively respond to two electromagnetic waves of horizontal polarization and vertical polarization; A second metallized via group is distributed around the square metal patch, the second metallized via group passes through 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 feeding port, and 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 sequentially spaced along the length direction of the square metal patch; Preferably, 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); Preferably, the ratio of the diameter D1 of the first metallized via hole, the spacing d between adjacent first metallized via holes, and the side length L of the square metal patch is (0.2-0.3): (0.5-1.5): (6-10).

3. The resonant sensitive structure according to claim 1, characterized in that: The four pad groups are centrally symmetrically distributed around the square metal patch; Preferably, the pad group includes a plurality of pads arranged in sequence and spaced apart in a direction away from the square metal patch, and the pads are parallel to the square metal patch; Preferably, the ratio of the length M of the pad to the side length L of the square metal patch is (2-4):(6-10).

4. The resonant sensitive structure according to claim 1, characterized in that: The second metallized via group includes four second metallized vias, and each of the second metallized vias corresponds to one of the pad groups; Preferably, the diameter D2 of the second metal via is smaller than the width of the pad; Preferably, each of the second metal vias is located in a geometric center area of ​​the pad group.

5. The resonant sensitive structure according to claim 1, characterized in that: The resonant sensitive structure is a square structure as a whole, and the side length of the square metal patch is less than or equal to the period length P of the resonant sensitive structure; Preferably, 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).

6. The resonant sensitive structure according to claim 1, characterized in that: The resonant layer is a centrally symmetrical structure; and / or the resonant sensitive structure as a whole is a mirror-symmetrical structure, the symmetry axis of the resonant sensitive structure coincides with a diagonal line of the square metal patch and passes through the orthogonal intersection points of the two first metallized via groups.

7. A fully polarized 360° reflective phase-adjustable coded metasurface device, comprising a plurality of digital coding units periodically arranged in the x and y directions and electrically connected in sequence, characterized in that: The digital encoding unit comprises a resonant sensitive structure as described in any one of claims 1 to 6, and four varactor active devices, wherein the four varactor active devices are respectively arranged on the four pad groups in a one-to-one correspondence, each of the varactor active devices is electrically connected to the square metal patch and a pad group, each of the digital encoding units can be individually controlled by a bias voltage applied to the varactor active device, and can be switched between different working states, and a first resonant cavity or a second resonant cavity is formed between two resonant cavity separation structures of two adjacent digital encoding units, and the first resonant cavity and the second resonant cavity have different sizes.

8. The fully polarized 360° reflective phase-adjustable coded metasurface device according to claim 7, characterized in that: The digital encoding unit further comprises four fixed capacitor elements, the four fixed capacitor element groups are respectively arranged on the four pad groups in a one-to-one correspondence, and each of the fixed capacitor elements is connected in series with a variable capacitance active device; Preferably, a second fixed capacitance element and a variable capacitance 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. Preferably, the varactor active device comprises a varactor diode.

9. The fully polarized 360° reflective phase-adjustable coded metasurface device according to claim 7 or 8, characterized in that: A plurality of the digital encoding units are combined into a plurality of sub-arrays, each of which includes 2×2 digital encoding units arranged in a mirror image, and each of the sub-arrays is a centrally symmetrical structure.

10. A method for achieving full polarization 360° reflection phase adjustment, characterized in that: include: A fully polarized 360° reflective phase-adjustable coding metasurface device as described in any one of claims 7 to 9 is provided, and bias voltage is independently applied to multiple varactor active devices of each of the digital coding units.

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