Independent adjustable broadband multi-bit metasurface unit structure

Abstract

The invention discloses an independent adjustable broadband multi-bit metasurface unit structure, which comprises the following steps of: designing an intelligent metasurface unit independently adjusted by a broadband 3b-it unit by using a resonance scattering analysis method, the low-loss broadband 3b-it phase modulation function of each unit can be achieved in the x-axis polarization direction by controlling the voltage values of the two sides of the varactors, unit bottom layer feeder line arrangement is designed, and the effect of unit independent regulation and control is achieved. Electromagnetic simulation software is utilized to optimize geometric parameters and output reflection electromagnetic response of the design model; the overall design of the intelligent metasurface panel is carried out based on the designed unit model, and the intelligent metasurface panel comprises a sub-panel composed of a plurality of variable capacitance diode-based broadband 3b-it unit independent reconfigurable intelligent metasurface units, and a control panel connected with an external feed device and a main panel.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a prototype design of a novel independently controllable broadband multi-bit metasurface unit structure in a sixth generation mobile communication system (the 6th generation, referred to as 6G for short). Background Art

[0002] In the future 6G network, hundreds of billions of wireless energy-consuming devices will be connected to the network. Large-scale base station nodes provide wide-area signal coverage, but also scatter a large amount of unused electromagnetic energy. Therefore, if these electromagnetic energies are used to provide green and sustainable energy for wireless devices while transmitting information, it can drive the transformation of the terminal equipment to low-power information transmission mode.

[0003] In traditional wireless energy transmission systems, far-field radiation solutions are costly, power-hungry, and inefficient, while near-field radiation is relatively more efficient, but has a limited transmission distance. Reconfigurable intelligent metasurfaces (RISs)-assisted wireless power transfer (WPT) can control the incident signal to achieve energy-focused transmission under low power consumption, high occlusion, and long-distance conditions. It has the potential to solve the problem of low transmission efficiency at a low cost and is expected to become a key candidate technology in future 6G industrial sensor networks, smart homes, smart wearables, and other scenarios.

[0004] According to the different positional relationships between the feed source and the metasurface, the metasurface morphology is divided into two types: reflective and reflective. The hardware design of both types theoretically supports energy transmission. However, due to the different energy transmission paths, the reflective metasurface cannot take into account both focusing efficiency and reconfigurable characteristics. Specifically, the reflective metasurface is used to realize energy focusing of the energy-reflective metasurface, and the unit is fixed and cannot be adjusted. At the same time, the reflective metasurface will add control lines when implementing phase adjustment. The electromagnetic wave reflection effect of the feed layer will significantly reduce the energy absorption efficiency of the metasurface, thereby reducing system performance. In order to ensure the system energy transmission efficiency and dynamic adjustable requirements, the reflective metasurface is more suitable for energy focusing transmission scenario applications.

[0005] The fixed, train-controlled, 1-bit control and other schemes widely used in existing research results cannot support high-precision broadband phase control, resulting in low focusing efficiency. Although refined control of metasurface units can improve focusing efficiency, it will inevitably increase the number of control lines and the complexity of phase calculation, and increase the difficulty of hardware system design.

[0006] Phase control is the most basic performance of reconfigurable metasurfaces, so solid-state electronic devices such as PI N diodes and varactor diodes are usually integrated into each metasurface element to dynamically control its phase response. However, the number of control paths and design complexity of the unit-independently controlled PI N diode metasurface based on the traditional frequency-selective surface principle increase significantly with the phase control accuracy. Therefore, most existing designs focus on 1-bit phase-independent reconfigurable metasurfaces based on PI N diodes, which are difficult to design and manufacture. The design and manufacture of multi-bit phase-independent reconfigurable metasurfaces based on broadband varactor diodes needs to be studied urgently. Summary of the invention

[0007] The purpose of the present invention is to provide an independently controllable broadband multi-bit metasurface unit structure, which can realize broadband 3-bit unit independent phase modulation function in the x-axis polarization direction by controlling the voltage values ​​on both sides of the varactor.

[0008] To achieve the above object, the present invention provides the following solutions:

[0009] An independently controllable broadband multi-bit metasurface unit structure, comprising a main panel composed of a plurality of phase-independent reconfigurable intelligent metasurface units based on varactor diode modulation, and a control panel connecting an external power feeding device and the main panel;

[0010] The broadband 3-bit unit independently regulates the metasurface unit to be a six-layer structure;

[0011] The first layer of the smart metasurface unit in the present invention is a metal layer, comprising two T-shaped copper metal patches in opposite directions, the two patches are connected using a varactor diode, the center of the first layer is taken as the origin, the connection direction of the varactor is set as the x-axis of the rectangular coordinate system, and the connection direction perpendicular to the x-axis is taken as the y-axis, and the following description methods all follow this principle;

[0012] The third layer of the smart metasurface unit in the present invention is a metal layer, which serves as a metal stratum to improve the reflection efficiency of the unit to electromagnetic waves;

[0013] In the present invention, the varactor diode of the intelligent metasurface unit is located between two T-shaped copper metal patches in opposite directions on the first metal layer. The capacitance of the varactor diode is changed by external DC feeding to control the degree of coupling between the electric resonance and magnetic resonance excited by the reflective metasurface unit, thereby controlling the change in the phase of the electromagnetic wave.

[0014] The second and fifth layers of the smart metasurface unit in the present invention are dielectric substrate layers, made of the same material but with different thicknesses, and the two metal through holes in the middle are used to connect the varactor diode in the first metal layer to the DC feeder of the sixth metal layer;

[0015] The fourth layer of the smart metasurface unit in the present invention is a dielectric bonding material layer, bonding the third layer to the fourth layer;

[0016] The two metal vias of the super surface in the present invention are located on the rectangular coordinate system and are evenly distributed on the x-axis;

[0017] The sixth layer of the smart metasurface unit in the present invention is a metal layer, which includes a DC feeder for connecting the top-layer diode, and is designed to be a feeder network connected to the varactor diode loaded in the first metal layer, wherein one side to which the voltage is applied is independently led out, and the other ground end is connected, thereby realizing the function of independently modulating the capacitance of the varactor diode loaded in the first metal layer of all units;

[0018] The reflective intelligent metasurface in the present invention comprises a reflective metasurface main panel and a feed control panel;

[0019] The reflective metasurface main panel is composed of 2×2 closely arranged metasurface sub-panels. Each reflective metasurface sub-panel is composed of 16×16 periodically arranged reflective metasurface units, where 16 rows of reflective metasurface units are arranged along the x-axis and 16 columns of reflective metasurface units are arranged along the y-axis.

[0020] Among them, the 16×16 metasurface units on all daughter boards are connected by independent DC bias lines through the metal patches on the sixth layer, and the varactor diode loaded in each individual smart metasurface unit is fed by a DC voltage source to improve the phase control accuracy of the metasurface and the electromagnetic wave control accuracy;

[0021] The feed control panel part consists of 1088 DC bias lines and 1088 ports, of which the 1088 DC feed ports include 1024 feed ports for different voltages and 64 ground ports for grounding;

[0022] Among them, 32 rows of smart metasurface units are connected to 32 DC bias lines corresponding to 32 feeding ports. These ports are divided into two groups and are evenly located on both sides of the y-axis of the entire metasurface board. 64 DC bias lines and 64 DC feeding ports are connected to the ground and evenly located on both sides of the y-axis of the entire board. The phase response of the main panel smart metasurface unit can be controlled by feeding DC voltage through an external control system;

[0023] The 1088 DC feeding ports in the present invention are composed of 1088 through-holes. The through holes corresponding to 32 units in a row on the y-axis are arranged horizontally along the y-axis and distributed on both sides of the metasurface. The design diameter of each through hole and the distance between the through holes are based on the model of the external control terminal connecting line.

[0024] Beneficial Effects

[0025] According to the specific embodiments provided by the present invention, the present invention achieves the following technical effects:

[0026] The present invention provides an independently controllable broadband multi-bit metasurface unit structure, comprising a plurality of reflective intelligent metasurface units based on independently controllable varactor diodes, wherein a varactor diode is integrated on each broadband 3-bit modulated independently controllable reflective intelligent metasurface unit along the x-axis polarization direction, and broadband 3-bit control of the reflection phase of all units can be achieved by controlling the voltage values ​​on both sides of the varactor diode.

[0027] The unit-independently controlled reflective intelligent metasurface unit of the present invention can achieve 3-bit regulation of the reflection phase in the x-axis polarization direction.

[0028] The unit-independently controlled reflective intelligent metasurface unit of the present invention has a minimum insertion loss of 1.851 dB and an average insertion loss of 0.906 dB within the range of reflection phase regulation in the x-axis polarization direction.

[0029] The unit-independently controlled reflective intelligent metasurface unit of the present invention has a central frequency of 2.0 GHz, a bandwidth of 1.92 GHz to 2.2 GHz, and a total bandwidth of 280 MHz. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 It is a schematic diagram of the metasurface homogenization modeling of the surface average impedance involved in the independently adjustable broadband multi-bit reflective intelligent metasurface unit designed by the present invention;

[0032] Figure 2 It is a topological schematic diagram of an independently controllable broadband multi-bit reflective intelligent metasurface unit designed by the present invention;

[0033] Figure 3 It is a schematic diagram of the first metal layer of the independently adjustable broadband multi-bit reflective smart metasurface unit designed by the present invention;

[0034] Figure 4 It is a schematic diagram of the third metal layer of the independently adjustable broadband multi-bit reflective intelligent metasurface unit designed by the present invention;

[0035] Figure 5It is a schematic diagram of the sixth metal layer of the independently adjustable broadband multi-bit reflective intelligent metasurface unit designed by the present invention;

[0036] Figure 6 It is a schematic diagram of a side view of an independently adjustable broadband multi-bit reflective intelligent metasurface unit designed by the present invention;

[0037] Figure 7 This is the current distribution diagram of the first metal layer of the independently adjustable broadband multi-bit reflective intelligent metasurface unit designed by the present invention;

[0038] Figure 8 It is a trend diagram of the phase variation of the reflection coefficient of the independently adjustable broadband multi-bit reflective intelligent metasurface designed by the present invention with respect to the frequency;

[0039] Fig. 9 It is a trend diagram of the insertion loss of the reflection coefficient of the independently adjustable broadband multi-bit reflective intelligent metasurface designed by the present invention changing with the frequency;

[0040] Fig.10 It is a schematic diagram of an independently adjustable broadband multi-bit reflective smart metasurface sub-panel designed by the present invention;

[0041] Fig.11 It is a schematic diagram of the overall panel composed of independently adjustable broadband multi-bit reflective intelligent metasurface sub-panels designed by the present invention;

[0042] Fig.12 A schematic diagram of an independently controllable broadband multi-bit reflective smart metasurface designed for the present invention being illuminated by a feed antenna under the excitation of an x-polarized electromagnetic wave;

[0043] Fig.13 The simulated electric field diagram of the independently controllable broadband multi-bit reflective smart metasurface near-field energy beam synthesis under the excitation of x-polarized electromagnetic waves designed for the present invention; DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] System architecture or scenario of application of the present invention

[0046] As an emerging sub-wavelength electromagnetic wave manipulation technology, configurable metasurfaces can achieve adjustable signal reflection phase and ideal multipath effect under low-loss conditions by integrating a large number of independent passive reflection units in two dimensions, and can realize energy focusing transmission through active beam control. Configurable metasurfaces will become an important foundation for wireless energy supply in future smart cities.

[0047] Detailed description of the reflective intelligent supersurface principle of the present invention

[0048] Metasurfaces are considered in the most general sense as surface distributions of electrically small resonant scatterers, characterized by electric and magnetic surface polarization densities. In bulk three-dimensional materials, the electric polarization density is a vector field that represents the density of permanent or induced electric dipole moments in dielectric materials. When a dielectric is placed in an external electric field, its molecules acquire electric dipole moments and the dielectric is said to be polarized.

[0049] A metasurface can be broadly defined as an array of polarized cells that induce electric and magnetic field discontinuities on either side of the surface. The goal of a macroscopic description of a metasurface is to express the discontinuities in the electric and magnetic fields as a function of the surface averaged electric and magnetic surface polarization densities. The macroscopic description of a metasurface involves replacing the actual spatial distribution of cells on the smart surface with an analytical relationship between the electric and magnetic fields on either side of the metasurface. By homogenizing (continuous) the electric and magnetic surface polarization densities, the size, shape, and physical properties of the cells are directly brought into these analytical relationships, and these parameters play an important guiding role in the design of metasurface cells.

[0050] Analytical relations that express the electric and magnetic fields on both sides of a metasurface as functions of the homogeneous (continuous) electric and magnetic surface polarization densities are called generalized thin sheet transition conditions (GSTCs). A macroscopic description of a metasurface that depends only on the average (macroscopic) electric and magnetic fields can be obtained by expressing the electric and magnetic surface polarization densities in terms of the magnetic susceptibility tensor instead of the polarizability. Similar to the mean field, the magnetic susceptibility tensor is a macroscopic surface average parameter. They can be viewed as effective parameters of the metasurface, similar to the dielectric constant and permeability of bulk metamaterials, which depend on the topology and geometry of the unit cells, the spacing between unit cells, the properties of the material, and the wavelength. The specific relationship is as follows

[0051]

[0052] in For a = {e, m} and b = {e, m}, are the (electro-electric, electro-magnetic, magnetic-electric and magnetic-magnetic) surface average (or simply surface) susceptibilities, which are macro quantities for simple but accurate synthesis and analysis of metasurfaces. Once the analytical expressions of the surface susceptibility functions are obtained, the next step is to map these functions to the physical structure of unit cells that can be realized and manufactured, and the mutual coupling between units needs to be considered during the design.

[0053] The average reflection coefficient of the metasurface implicitly explains the mutual coupling between the metasurface unit cells and the inherent coupling between the phase response and amplitude response of the surface magnetic susceptibility function. In order to consider the mutual coupling relationship between the units, the surface average reflection coefficient is analyzed below. Abnormal reflection simulated by surface average impedance.

[0054] A perfect anomaly reflector can be obtained by applying Figure 1 The equivalent transmission line representation of the metasurface structure shown is used to represent the average surface impedance. According to the electromagnetic field transformation, the voltage and current on both sides of the metasurface structure can be obtained:

[0055]

[0056] Applying Kirchhoff's circuit laws to Figure 1 The equivalent transmission line in can be obtained as follows:

[0057]

[0058] The surface average impedance as a function of the electromagnetic field transformation to be achieved is given by:

[0059]

[0060] Therefore, Z 1 (x) is the surface average impedance that determines the properties of the designed metasurface structure and the electromagnetic response, and its benchmark analytical formula can be obtained as:

[0061]

[0062] Where η is the intrinsic impedance in vacuum, A r is the proportional factor, Φ(x)=exp(-jk(sin(θ r )-sin(θ i ))x) is a shorthand notation. Z based on the surface average impedance x Definition. In the context of designing and engineering metasurfaces, the surface average reflectance is usually defined as

[0063]

[0064] After determining the average reflection coefficient of the metasurface, in order to make the designed metasurface meet different performance requirements, it is necessary to introduce analytical theories such as incident electromagnetic waves, reflected electromagnetic waves, and surface electromagnetic waves, further obtain the function of the general magnetic susceptibility function, and optimize the unit design parameters.

[0065] Detailed description of the reflective intelligent metasurface unit of the present invention

[0066] The topological diagram of the broadband multi-bit reflective intelligent metasurface unit designed by the present invention is shown in the attached figure. Figure 2 As shown, the top metal layer design drawing, the third metal layer design drawing, the bottom layer design drawing, and the side view are as shown in the attached Figure 3 , 4 , 5, and 6. The electric small resonant scattering element is composed of an antisymmetric T-type dipole pair etched on the surface of the F4B substrate, and the dipole pair is distributed along the x-axis. For a pair of antisymmetric metal patterns, a surface current with a time delay is excited on the surface of the metal layer. Due to the time delay, the upper and lower dipoles sometimes present the same surface current direction and sometimes present opposite surface current directions. The two correspond to the even-mode coupling and odd-mode coupling between the surface currents, which excite electric resonance and magnetic resonance, respectively. Under appropriate conditions, when the impedance matching that satisfies the electromagnetic resonance is designed, the phase change can be maximized at the resonance point and a wider bandwidth can be achieved.

[0067] In order to adjust the electromagnetic response phase, the present invention loads a varactor diode to modify the impedance change of the dipole pair, thereby changing the electromagnetic coupling degree between the orthogonal units, thereby achieving broadband controllable modulation of the reflection phase while ensuring high reflectivity. The feeding network of the sixth metal layer is designed with emphasis, and the varactor diodes of the upper metal layer are bridged by metal bias lines and metal vias, and connected to the control port by densely arranging the bias lines, so as to realize independent feeding of all unit diodes on the entire intelligent metasurface board.

[0068] The present invention determines a set of optimal geometric parameter values ​​by adjusting the geometric parameters of the metasurface unit period, the geometric parameters of the T-shaped copper metal patch in the first layer, the geometric parameters of the DC feeder in the sixth metal layer, and the geometric parameters of the thickness of the two-layer dielectric substrate, so as to adjust the resonant frequency of the entire metasurface unit and maximize the phase variation range of the intelligent metasurface unit controlled by the varactor diode and minimize the insertion loss.

[0069] The size of the reflective intelligent metasurface periodic unit designed by the present invention is P=30 mm, and the thickness of the second and fifth layers of F4B dielectric substrates are d=3 mm and d 3 =0.2mm, dielectric constant ε r =2.65, loss coefficient tanδ=0.005; the fourth layer medium is PP adhesive, with a thickness of d 2 =0.1mm, dielectric constant εr =4.2, loss coefficient tanδ = 0.004. In order to adjust the electromagnetic coupling between the units and make the unit center frequency close to 2GHz, the parameter l2 should be as large as possible.

[0070] The specific dimensions of the reflective intelligent metasurface unit designed in the present invention are shown in the following table:

[0071]

[0072] The varactor diode model used in the present invention is MAVR-000020-1411. As the voltage changes from 0V to 15V, the equivalent capacitance of the diode changes continuously from 0.95pF to 0.14pF, and the equivalent inductance and equivalent resistance are 0.02nH and 0.88Ω respectively. The characteristic of the varactor diode's continuous change in capacitance is the basis for the intelligent metasurface to achieve multi-bit phase control.

[0073] The odd-mode coupling of the reflective metasurface current designed by the present invention is shown in the attached Figure 7 As shown, it can be found that the top layer excites a strong current distribution in the opposite direction, that is, it excites magnetic resonance, that is, a resonant scatterer metasurface element working in the 2 GHz frequency band.

[0074] The present invention uses the commercial software Ansys HFSS to perform full-wave simulation on the electromagnetic response of the metasurface unit of the present invention. The results of the simulated reflection response are shown in the attached figure. Figure 8 and attached Fig. 9 As shown in the figure, since the varactor diode can continuously change the capacitance value with the external voltage, several sets of specific voltage values ​​corresponding to the capacitance values ​​can be selected to realize multi-bit phase encoding.

[0075] The metasurface unit designed in the present invention intends to adopt a 3-bit coded modulation mode, which improves the accuracy of beam design compared to lower bit coded modulation responses. Figure 8 As shown, at the center frequency of 2GHz, the selected capacitance values ​​are 0.14pF, 0.237pF, 0.282pF, 0.371pF, 0.406pF, 0.439pF, 0.513pF, and 0.766pF, respectively, and the corresponding difference of each phase state is approximately 45 degrees, which can achieve accurate 3-bit phase encoding. In the frequency range of 1.92GHz-2.2GHz, the phase response of the reflective metasurface unit of the present invention changes from 0.14pF to 0.95pF with the varactor diode, and the phase difference is greater than 315 degrees, so 3-bit phase modulation can be achieved.

[0076] Furthermore, as attached Fig. 9As shown in the figure, at a phase modulation frequency of 2 GHz, the minimum insertion loss of the reflective metasurface unit of the present invention is 1.851 dB, the average insertion loss is 0.906 dB, the central frequency of the unit regulation is 2.0 GHz, the bandwidth is 1.92 GHz to 2.2 GHz, and the total bandwidth is 280 MHz. Compared with the currently designed unit-independent adjustable metasurface, the loss is significantly reduced, and the 3-bit regulation bandwidth is significantly improved, which can more efficiently reflect and manipulate the incident wave.

[0077] Detailed description of the reflective smart supersurface of the present invention

[0078] After designing the structure of a single reflective intelligent metasurface unit and confirming its phase and reflection loss characteristics through full-wave simulation, the present invention designs a reflective intelligent metasurface panel that can actually be processed using printed circuit board technology. The reflective intelligent metasurface prototype board designed by the present invention includes a sub-panel composed of multiple reflective intelligent metasurface units, a control panel responsible for connecting the main panel with an external power supply, and a detachable bracket that tightly fixes the sub-panel.

[0079] The reflective intelligent metasurface sub-panel designed by the present invention is composed of 16*16=256 metasurface units, among which 16 rows of reflective metasurface units are arranged along the x-axis, and 16 columns of reflective metasurface units are arranged along the y-axis; the metal patches of the sixth metal layer of adjacent intelligent metasurface units on the y-axis are independently led out, and 16 independent DC bias lines are used to connect to the voltage power supply of the control panel on the other side of the y-axis, and an independent DC bias line is used on the sixth metal layer to connect to the grounding of the control panel on the other side of the y-axis, and the varactor diode loaded in each independent unit on the metasurface is fed by a DC voltage source, thereby greatly improving the accuracy of metasurface beam control.

[0080] The reflective intelligent metasurface total panel designed by the present invention is composed of 2*2=4 metasurface sub-panels, with a total of 32×32=1024 independently controllable units. Since the designed control panel is located on one side of the sub-panel, the tight arrangement of all units on the four sub-panels can be achieved through rotation and splicing, maintaining the array characteristics of the metasurface. The larger aperture can reflect the incident electromagnetic waves with higher efficiency, and at the same time achieve extremely high-precision beam control in the near field range.

[0081] The feed control panel part of the reflective intelligent metasurface sub-panel designed by the present invention is composed of 272 DC bias lines and 272 ports, wherein the 272 DC feed ports include 256 feed ports with different voltages and 16 grounding ports, 16×16 intelligent metasurface units are connected to the 256 DC bias lines corresponding to the 256 feed ports, 16 rows of 16 DC bias lines and 16 DC feed ports are connected to ground, and the phase response of the main panel intelligent metasurface unit can be controlled by feeding DC voltage through an external control system.

[0082] The 272 DC feed ports in the sub-panel of the present invention are composed of 272 through-holes, which are arranged in a row of 17 holes and 16 rows in total along the x-axis. The distance between each through hole is based on the model of the external control terminal connecting line. The design parameters are a through hole diameter of 1 mm and a distance between through holes of 2.54 mm, which meet the size requirements of DuPont wires and pins on the market.

[0083] The present invention simulates the performance of the designed reflective intelligent metasurface panel for beam manipulation by setting the simulation conditions of a rectangular aperture horn antenna irradiating the reflective metasurface panel in an actual scenario. Fig.12 As shown, a feed antenna with a center frequency of 2 GHz is generated through the ADK toolbox in HFSS, and the feed distance is set to be 0.1 m perpendicular to the center of the metasurface. The compensation value of the phase of different units of the reflective metasurface when the beam is deflected is calculated according to the principle of near-field energy beam focusing and beam coherence superposition, which corresponds to the capacitance of the varactor diode after being normalized to 3-bit encoding. When setting up the simulation, it is necessary to set up a FEB I solver on the feed and metasurface side, that is, a finite element-integral equation hybrid algorithm solver. Place an energy beam receiving plane, observe the electric field amplitude distribution diagram on the receiving plane to view the energy beam focusing effect, and calculate the Poincinnati vector integral on the receiving plane to obtain the metasurface radiation energy, as shown in the attached figure. Fig.13 The reflective intelligent super surface of the present invention can achieve a significant energy beam focusing effect.

[0084] Future prospects of the present invention

[0085] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. It provides a groundbreaking expansion of ideas for future researchers in the prototype design of reflective smart metasurfaces. The description of the above embodiments is only used to help understand the method and core ideas of the present invention; obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. In this way, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. An independently controllable broadband multi-bit metasurface unit structure, characterized in that: The reflective metasurface comprises: a main panel comprises a plurality of high-reflectivity reflective intelligent metasurface units capable of independently controlling modulation of varactor diodes, the units being arranged periodically in the same plane, and a metasurface unit matrix having a special reverse symmetric T-shape being arranged in a plane perpendicular to the incident electromagnetic wave; The characteristics of this metasurface unit are: a special reverse symmetrical T-shaped top patch optimized for broadband 3-bit design, with a varactor diode loaded in the middle of the patch; a specially designed bottom feed line arrangement, with a row of units as a group, and its control feed line is led to one side of the metasurface panel, so as to achieve interference-free independent phase control of all metasurface units without affecting broadband 3-bit control; the metasurface unit is connected to the external feed power supply and the main panel by the control panel, and the phase of the electromagnetic wave is modulated by changing the capacitance value of the varactor diode.

2. The reflective metasurface unit according to claim 1 is a six-layer structure, consisting of three layers of dielectric substrate and three layers of metal; The first layer is a metal layer, comprising two T-shaped copper metal patches in opposite directions, the two patches are connected using a varactor diode, the center of the first layer is taken as the origin, the connection direction of the varactor diode is set as the x-axis of the rectangular coordinate system, and the connection direction perpendicular to the x-axis is taken as the y-axis; The third layer in the middle is a metal layer, which serves as a metal stratum to improve the unit's reflection efficiency for electromagnetic waves; The sixth layer of the bottom layer is a metal layer, which is connected to the top layer diode as a DC feeder; The second and fifth layers are dielectric substrate layers; The fourth layer is a dielectric bonding material layer, bonding the third layer to the fourth layer; By connecting a DC voltage to the sixth-layer DC feeder, the voltage difference on both sides of the varactor diode in the first metal layer is changed, thereby changing the phase change range of the reflective metasurface unit.

3. The reflective metasurface unit according to claim 2, characterized in that: The varactor diode is located between two T-shaped copper metal patches in opposite directions on the first metal layer. The capacitance of the varactor diode is changed by external DC feeding to control the degree of coupling between the electric resonance and magnetic resonance excited by the reflective metasurface unit, thereby controlling the change in the phase of the electromagnetic wave.

4. The reflective metasurface unit according to claim 2, characterized in that: The sixth metal layer is designed as a feeder network connecting the varactor loaded in the first metal layer, wherein one side to which the voltage is applied is led out separately and the other side is connected to the ground, thereby realizing the function of using independent voltages to control the capacitance of the varactor loaded in the first metal layer of the independent unit.

5. The reflective metasurface unit according to claim 2, characterized in that: By adjusting the geometric parameters of the metasurface unit period, the geometric parameters of the T-shaped copper metal patch in the first metal layer, the geometric parameters of the DC feed line in the sixth metal layer, the geometric parameters of the thickness of the two dielectric substrates, and The dielectric constant and loss tangent parameters of the material determine a set of optimal geometric and material parameter values ​​so that the phase variation range of the reflective metasurface unit controlled by the varactor diode is maximized, the bandwidth is maximized, and the insertion loss is minimized.

6. The reflective smart metasurface according to claim 1, characterized in that It consists of a reflective metasurface main panel and a control panel; The main panel is composed of 32×32 reflective intelligent metasurface units arranged in a periodic pattern; 32 rows of reflective metasurface units are arranged along the x-axis, and 32 columns of reflective metasurface units are arranged along the y-axis; The main panel is composed of four reflective intelligent metasurface sub-panels, which are composed of 16×16 periodically arranged metasurface units. The control panel part of each sub-panel is composed of 272 DC bias lines and 272 ports, of which the 272 DC feed ports include 256 feed ports with different voltages and 16 grounded ports. The phase response of each unit on the reflective metasurface of the main panel can be controlled by feeding DC voltage through an external control system.

7. The reflective smart metasurface according to claim 6, characterized in that: Each unit on the metasurface has a DC voltage feeder connected to it, which can independently feed the varactor diode loaded in each different unit on the metasurface, greatly improving the control accuracy of the metasurface phase response and achieving more complex electromagnetic wave manipulation.

8. The reflective smart metasurface according to claim 6, characterized in that: The reflective metasurface is composed of four reflective metasurface sub-boards with 16*16 units, which are closely spliced ​​to form an integral unit to independently control the reflective metasurface. The 256 units on the sub-board are connected to 256 DC bias lines corresponding to 256 feed ports, and 16 DC bias lines and 16 DC feed ports are connected to ground; The DC feed port of the entire reflective metasurface board is composed of 1088 through-holes. The through holes corresponding to a row of 32 units on the y-axis are arranged horizontally along the y-axis and distributed on both sides of the metasurface. The design diameter of each through hole and the distance between the through holes are based on the model of the external control terminal connecting wire.

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