Broadband intelligent metasurface

Abstract

The invention discloses a broadband intelligent metasurface, and the metasurface is characterized in that the left part and the right part of a metal radiation patch are respectively and additionally provided with an open rectangular ring metal groove, and the two added open rectangular ring metal grooves are symmetrically arranged in the metal radiation patch in a manner that the openings face inwards; in this way, a new resonance mode with the frequency of f4 is introduced into the two open rectangular ring metal grooves in the off state of the intelligent metasurface unit, so that the phase shift range of the intelligent metasurface unit is expanded, and the phase bandwidth of the intelligent metasurface unit is increased. Compared with a traditional intelligent metasurface, the broadband intelligent metasurface has a wider working bandwidth, improves the channel capacity of a communication system, supports a higher data transmission rate, and better resists multipath interference and frequency selective fading, thereby improving the reliability of signals and the communication quality. According to the broadband intelligent metasurface, broadband electromagnetic signals can be regulated and controlled at the same time through one metasurface, and the design and deployment cost of the intelligent metasurface can be effectively saved in application deployment.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communications, and more specifically, relates to a broadband intelligent metasurface. Background Art

[0002] With the continuous development of 5G\B5G communication technology, various communication devices have an increasing demand for high transmission rates. According to Shannon's theorem, the communication transmission rate is directly related to the signal bandwidth. Therefore, in order to meet the application requirements of high communication rates, wireless communication systems are gradually expanding to high frequencies to obtain spectrum resources with large bandwidths. However, high-frequency signals have short wavelengths and small coverage. Traditional technical solutions such as increasing the number of sites and active relays can expand the coverage of high-frequency signals, but at the same time they also greatly increase the cost and power consumption of the communication system.

[0003] Reconfigurable Intelligent Surface (RIS) is a new type of electromagnetic metamaterial technology with the advantages of low cost, low power consumption, and flexible deployment. By adjusting the electromagnetic characteristics of each unit on the intelligent metasurface, such as phase, amplitude, and polarization, the propagation direction of electromagnetic waves in space can be dynamically controlled, thereby opening up new transmission paths in wireless communication systems. Using intelligent metasurfaces to assist base station communications can expand their signal coverage at a lower cost and power consumption, thereby improving the channel environment.

[0004] A millimeter wave smart metasurface unit and a millimeter wave smart metasurface are disclosed in a Chinese invention patent with authorization announcement number CN113206386B published on May 31, 2022. Figure 1As shown, it includes: a first metal layer 1, a first dielectric substrate 2, a second metal layer 3, a second dielectric substrate 4 and a feed layer stacked in sequence; the first metal layer 1 is a square structure, and a long strip branch extends from one side of one of its wide sides, on which a gap is etched, and a switch device 6 is loaded at the gap; the second metal layer 3 serves as a metal floor; the end 7 of the long strip branch away from the square structure is connected to the second metal layer 3 through a conductive column passing through a via hole on the first dielectric substrate 2; the feed layer serves as a positive electrode; the feed layer is connected to the center of the first metal layer 1 after passing through the second dielectric substrate 4, the second metal layer 3 and the via hole on the first dielectric substrate 2 in sequence through the second conductive column; in different states of the switch device 6, the unit presents two different logical states. This invention can solve the problems of millimeter wave shielding and high equipment deployment costs in millimeter wave communications. The millimeter wave intelligent metasurface unit provided by the invention has an explicit analytical expression relationship between the length px and width py of the first metal layer 1 and the desired operating frequency and the reflection phase difference at the operating frequency. By adjusting the length px and width py of the first metal layer, millimeter wave communication at any operating frequency in the 5G communication millimeter wave band (including n257 band, n258 band, n261 band, n259 band and n260 band) can be achieved. It has a wider range of application and can be better adapted to the 5G communication millimeter wave band.

[0005] like Figure 1 As shown, the smart metasurface of this invention patent can achieve 5G communication millimeter wave frequency band by adjusting the length px and width py of the first metal layer 1. However, once the length and width of the square structure of the first metal layer 1 are given, the processed smart metasurface works in the communication millimeter wave frequency band, and the working bandwidth is narrow, which is difficult to meet the application requirements of large bandwidth and high communication rate, which will limit the application potential of smart metasurfaces in assisting mobile communications.

[0006] A millimeter-wave frequency band reconfigurable reflective metasurface unit and its beamforming device are disclosed in a Chinese invention patent application with publication number CN116937173A published on October 24, 2023. Figure 2 As shown, by loading the PIN diode phase shifter 6, the short-circuit fan 7 and the unit control lead into the reconfigurable reflective metasurface unit in the millimeter wave frequency band, and using the shift register to fan out each unit control signal, the intensity, phase and polarization of the electromagnetic wave can be significantly adjusted, so that the reconfigurable metasurface has a very wide working frequency bandwidth, and the PIN diode realizes 0° and 180° phase shift for the vertically polarized electromagnetic wave in both the on and off states. The feed horn feeds power to the center of the reconfigurable metasurface. Through the phase shift encoding of the FPGA control board, the reconfigurable metasurface can realize efficient beamforming, and has the characteristics of compact structure, integrated microwave digital circuit control, wide beam scanning range, high beam gain and low side lobe, low microwave loss and low cost.

[0007] like Figure 2 As shown, the PIN diode phase shifter 6 includes a first T-shaped patch 6-1 and a second T-shaped patch 6-2 which are symmetrically arranged to form an I-shaped structure, a gap 6-3 is left between the first T-shaped patch 6-1 and the second T-shaped patch 6-2, and a PIN diode 6-4 is connected to the center between the first T-shaped patch 6-1 and the second T-shaped patch 6-2 across the gap 6-3. This structure enables the millimeter wave frequency band reconfigurable reflective metasurface unit provided by the invention to operate at a millimeter wave frequency of 26-30GHz. The operating frequency band is increased, but it is still difficult to meet the application requirements of large bandwidth and high communication rate. Therefore, research on intelligent metasurfaces with a wide operating frequency band has great application value. Summary of the invention

[0008] The purpose of the present invention is to overcome the shortcomings of the prior art that the bandwidth is narrow and it is difficult to meet the needs of broadband high-speed mobile communications, and to provide a broadband intelligent metasurface that can increase the channel capacity of the communication system, support higher data transmission rates, and better resist multipath interference and frequency selective fading, thereby improving signal reliability and communication quality.

[0009] To achieve the above-mentioned purpose of the invention, the broadband intelligent metasurface of the present invention is composed of a plurality of intelligent metasurface units arranged periodically, and the DC control channel of each intelligent metasurface unit is independently designed. Each intelligent metasurface unit includes a five-layer structure, which includes the following from top to bottom:

[0010] The first layer is a metal radiation patch, which receives incident electromagnetic waves in space and radiates them into free space after phase modulation.

[0011] The second layer structure is a first dielectric substrate, and the metal radiation patch is placed on the first dielectric substrate;

[0012] The third structure is a metal floor, which is attached below the first dielectric substrate;

[0013] The fourth layer structure is a second dielectric substrate, which is placed under the metal floor;

[0014] The fifth layer structure is a metal DC feeding network, which is placed below the second dielectric substrate;

[0015] The metal radiation patch is divided into left and right parts by a longitudinal metal groove, and the left and right parts are respectively connected to the positive electrode and the negative electrode of the reconfigurable switch device, wherein the part connected to the positive electrode of the reconfigurable switch device passes through the first dielectric substrate, the metal floor and the second dielectric substrate through the positive metal via to be connected to the positive electrode corresponding to the smart metasurface unit in the metal DC feed network, a metal isolation ring is arranged at the positive metal via in the metal floor to isolate the positive metal via from the metal floor, and the part connected to the negative electrode of the reconfigurable switch device passes through the first dielectric substrate, the metal floor and the second dielectric substrate through the negative metal via to be connected to the negative electrode corresponding to the smart metasurface unit in the metal DC feed network, and the negative metal via in the metal floor is connected to the metal floor;

[0016] It is characterized in that the reconfigurable switch device is placed on the longitudinal metal groove, connecting the left and right parts of the metal radiation patch, and the width of the longitudinal metal groove is W s1 and the length L of the reconfigurable switch device p1 Satisfy the relationship: W s1 <L p1 , the length of the longitudinal metal groove L s1 satisfy:

[0017]

[0018] Among them, ε r1 is the dielectric constant of the first dielectric substrate, f2 is the frequency of the resonant mode added by the longitudinal metal groove in the open state of the smart metasurface unit, and c is the speed of light in free space;

[0019] The left and right parts of the metal radiation patch are of the same size, and each has an open rectangular ring metal groove. The open rectangular ring metal groove is placed symmetrically in the metal radiation patch with its opening facing inward. The width of the open rectangular ring metal groove in the left and right directions is W s2 The width W of the metal radiation patch on the left and right sides p1 Need to meet W p1 >W s2 , the dimensions of the open rectangular ring metal groove need to meet:

[0020]

[0021] W s2 ≤L s2 ≤1.5×W s2

[0022] Among them, L s2 L is the length of the open rectangular ring metal groove in the vertical direction, sub is the length of the opening part of the open rectangular ring metal slot, and f4 is the frequency of the resonant mode added by the open rectangular ring metal slot in the closed state of the smart metasurface unit.

[0023] The object of the present invention is achieved in this way.

[0024] The broadband intelligent metasurface of the present invention adds an open rectangular ring metal groove to the left and right parts on the basis of the existing left and right parts of the metal radiation patch, and the two added open rectangular ring metal grooves are symmetrically placed with the openings facing inward in the metal radiation patch. In this way, the two open rectangular ring metal grooves will introduce a new resonance mode with a frequency of f4 when the intelligent metasurface unit is in the off state, thereby expanding the phase shift range of the intelligent metasurface unit and increasing the phase bandwidth of the intelligent metasurface unit.

[0025] Compared with the prior art, the broadband intelligent metasurface of the present invention has the following advantages and beneficial effects:

[0026] 1. The broadband smart metasurface of the present invention has a phase shift range of 23.8-45.5 GHz at 180±20°, and a relative working bandwidth of 62.6%. Compared with the traditional smart metasurface, the broadband smart metasurface of the present invention has a wider working bandwidth. According to Shannon's theorem, it can improve the channel capacity of the communication system and support higher data transmission rates;

[0027] 2. The broadband intelligent metasurface of the present invention can process electromagnetic signals of multiple frequency bands simultaneously, thereby improving the flexibility and freedom of the communication system. Thanks to the broadband characteristics, the broadband intelligent metasurface of the present invention can better resist multipath interference and frequency selective fading, thereby improving signal reliability and communication quality;

[0028] 3. When traditional narrowband smart metasurfaces assist broadband wireless communications, multiple narrowband smart metasurfaces need to be designed and deployed to cover broadband signals. However, the broadband smart metasurface of the present invention can simultaneously regulate broadband electromagnetic signals with only one piece, which can effectively save the design and deployment costs of smart metasurfaces in application deployment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of a millimeter wave intelligent metasurface unit in the prior art;

[0030] Figure 2 It is a structural schematic diagram of a millimeter wave frequency band reconfigurable reflective metasurface unit in the prior art;

[0031] Figure 3 It is a structural schematic diagram of a specific implementation mode of the broadband intelligent metasurface of the present invention;

[0032] Figure 4 It is a structural explosion diagram of a specific implementation mode of the smart metasurface unit of the broadband smart metasurface of the present invention;

[0033] Figure 5 yes Figure 4 The reflection phase curve diagram of the smart metasurface unit in the on and off states shown;

[0034] Figure 6 yes Figure 4 The reflection phase difference curve of the smart metasurface unit in the on and off states shown;

[0035] Figure 7 yes Figure 4 The reflection amplitude curves of the smart metasurface unit in the on and off states are shown;

[0036] Figure 8 Schematic diagram of the broadband evolution process of the intelligent metasurface unit in the broadband intelligent metasurface of the present invention, wherein the upper row is the structural evolution process, and the lower row is the reflection characteristic curve diagram of the corresponding intelligent metasurface unit in the on and off states;

[0037] Fig. 9 It is a phase difference curve in the on and off states during the broadband evolution of the smart metasurface unit in the broadband smart metasurface of the present invention;

[0038] Fig.10 It is a structural schematic diagram of a specific implementation of a broadband smart metasurface array composed of 16×16 smart metasurface units;

[0039] Fig.11 yes Fig.10 Schematic diagram of the feeding line network of the broadband smart metasurface array shown. DETAILED DESCRIPTION

[0040] The specific implementation of the present invention is described below in conjunction with the accompanying drawings so that those skilled in the art can better understand the present invention. It should be noted that in the following description, when the detailed description of known functions and designs may dilute the main content of the present invention, these descriptions will be omitted here.

[0041] The broadband smart metasurface is composed of multiple smart metasurface units arranged periodically, and the DC control channel of each smart metasurface unit is independently designed. The smart metasurface unit is usually composed of a reconfigurable switch device, a radiating metal layer, a dielectric substrate layer and a metal floor. The smart metasurface unit can be equivalent to a single-mode resonant circuit. By independently controlling the switching signals of each unit on the broadband smart metasurface, the resonant frequency and phase state of the unit are changed, thereby realizing dynamic regulation of electromagnetic waves in space.

[0042] The traditional intelligent metasurface unit only excites one resonant mode f1 and f3 in the on and off working states, and because the phase curve range of the single-mode resonant circuit is (-180°, 180°). Therefore, the phase difference curve of the on and off states of the traditional intelligent metasurface unit has only one extreme point. The working bandwidth index of the intelligent metasurface unit is generally the frequency range of the phase difference in the range of 180±20°, while the phase difference curve of the traditional intelligent metasurface unit has only one extreme point, which limits its working bandwidth.

[0043] The phase curve range of the smart metasurface unit is related to the resonant circuit. A new resonant structure is introduced on the basis of the single-mode resonance of the smart metasurface unit itself to expand the phase curve range of the unit, thereby introducing multiple extreme points in the phase difference curve of the unit on and off states. By adjusting the relative position of the resonant frequency of each resonant structure, the extreme points of the phase difference curve of the unit on and off states can be adjusted to achieve unit bandwidth expansion.

[0044] If the resonant frequencies of the smart metasurface units in the on state are f1, f2, … f n (where f1 represents the single-mode resonant frequency of the smart metasurface unit in the on state, f2,…f n represents the resonant frequency of the newly introduced loop); the unit resonant frequencies in the off state of the smart metasurface are f n+1 , f n+2 ,…f n+m (where f n+1 represents the single-mode resonant frequency of the smart metasurface unit in the off state, f n+2 ,…f n+m represents the resonant frequency of the newly introduced loop, and the value range of m is n-1, n, n+1). In order to achieve unit phase expansion, the resonant frequency must satisfy the inequality f1 <f n+1 <f2<f n+2 <… <f n <f n+m or n+1 <f1<f n+2 <f2<…<f n+m <f n The more resonant loops the smart metasurface unit introduces in the on and off states, the greater the phase bandwidth of the unit is broadened.

[0045] The number of extreme points N of the phase difference curve between the on and off states of the smart metasurface unit is related to the number of resonant modes of the smart metasurface unit in the on and off states (the number of resonant modes of the smart metasurface unit in the on state is n, and the number of resonant modes of the smart metasurface unit in the off state is m), and the specific mathematical relationship is N = m + n-1. Therefore, the introduction of a new resonant mode can increase the number of extreme points of the phase difference curve between the on and off states of the smart metasurface unit, and by adjusting the position of the resonant mode, the extreme point can be optimized to within the range of 180 ± 20°, thereby effectively expanding the phase bandwidth of the smart metasurface unit.

[0046] Based on the above design ideas, the present invention designs a broadband intelligent metasurface that can improve the channel capacity of the communication system, support higher data transmission rates, better resist multipath interference and frequency selective fading, and thus improve signal reliability and communication quality. The details are as follows:

[0047] In this embodiment, if Figure 1 As shown, the broadband intelligent metasurface of the present invention is composed of a plurality of intelligent metasurface units arranged periodically, and the DC control channel of each intelligent metasurface unit is independently designed. Each intelligent metasurface unit includes a five-layer structure, which includes the following from top to bottom:

[0048] The first layer structure is a metal radiation patch 1, whose function is to receive electromagnetic waves incident in space and radiate them into free space after phase modulation;

[0049] The second layer structure is a first dielectric substrate 2, and a metal radiation patch 1 is placed above the first dielectric substrate 2. The first dielectric substrate 2 is placed below the metal radiation patch 1, and its function is to serve as a high-frequency dielectric material, support the metal structures on the upper and lower surfaces, and affect the propagation speed and characteristic impedance of electromagnetic waves;

[0050] The third layer structure is a metal floor 3, which is attached below the first dielectric substrate 2 and is used to reflect electromagnetic waves;

[0051] The fourth layer structure is a second dielectric substrate 4, which is placed under the metal floor 3. Its main function is to support the DC feed network 5 and will not interfere with electromagnetic waves.

[0052] The fifth layer structure is a metal DC feeding network 5, which is placed below the second dielectric substrate 4 and is used to regulate the unit state.

[0053] Figure 4 It is a structural explosion diagram of a specific implementation mode of the intelligent metasurface unit of the broadband intelligent metasurface of the present invention.

[0054] In this embodiment, if Figure 4As shown, it can be seen that a longitudinal metal slot 8 and a pair of open rectangular ring metal slots 6 are loaded on the metal radiation patch 1 in the first layer structure of the smart metasurface unit. The metal slot can be equivalent to a parallel resonant circuit. The longitudinal metal slot 8 and the pair of open rectangular ring metal slots 6 respectively add a resonance with a frequency of f2 and f4 in the on and off states of the smart metasurface unit (state 1 is the off state, state 2 is the on state), thereby increasing the phase bandwidth of the unit. In this way, plus the resonant frequency f1 of the smart metasurface unit in the on state and the resonant frequency f3 of the off state, the smart metasurface unit has two resonant frequencies f1 and f2 in the on state, and two resonant frequencies f3 and f4 in the off state.

[0055] In addition to introducing a new resonance mode when the smart metasurface unit is in the on state, the longitudinal metal groove 8 also extends the current path of the smart metasurface unit in the on state, thereby reducing the resonance frequency f1 of the smart metasurface unit itself in the on state.

[0056] Specifically, if Figure 4 As shown, the metal radiation patch 1 is divided into two left and right parts by a longitudinal metal groove 8, and the left and right parts are respectively connected to the positive and negative electrodes of the reconfigurable switch device 7, wherein the part connected to the positive electrode of the reconfigurable switch device 7 passes through the first dielectric substrate 2, the metal floor 3 and the second dielectric substrate 4 through the positive metal via (the metal via 9 on the left) to be connected to the positive electrode corresponding to the smart metasurface unit in the metal DC feeding network 5, and a metal isolation ring 10 is arranged at the positive metal via (the metal via 9 on the left) in the metal floor 3 to isolate the positive metal via (the metal via 9 on the left) from the metal floor 3, and the part connected to the negative electrode of the reconfigurable switch device 7 passes through the first dielectric substrate 2, the metal floor 3 and the second dielectric substrate 4 to be connected to the negative electrode corresponding to the smart metasurface unit in the metal DC feeding network 5 through the negative metal via (the metal via 9 on the right), and the negative metal via (the metal via 9 on the right) in the metal floor 3 is connected to the metal floor 3.

[0057] In order to isolate the RF signal from the DC control signal, a metal filter fan-shaped branch 11 is loaded at the connection between the positive electrode corresponding to the smart metasurface unit and the positive metal via (the metal via 9 on the left) in the metal DC feeding network 5. The metal filter fan-shaped branch 11 is equivalent to a capacitor, which can filter out the high-frequency signal on the metal DC feeding network 5, thereby eliminating the influence of the metal DC feeding network 5 on the reflection performance of the smart metasurface unit.

[0058] In this embodiment, the first dielectric substrate 2 is made of high-frequency dielectric material such as F4BTMS-220 and Rogers 5880, with a dielectric constant of 2.2 and a thickness of 1.016 mm. The second dielectric substrate 4 is made of FR4 material, with a dielectric constant of 4.4 and a thickness of 0.2 mm.

[0059] In this embodiment, the model of the reconfigurable switch device 7 is madp000907-14020P.

[0060] In this embodiment, the copper foil thickness of the metal radiation patch 1 and the metal DC feeding network 5 is 1 oz, and the copper foil thickness of the metal floor 3 is 0.5 oz.

[0061] In this embodiment, the reconfigurable switch device 7 is placed on the longitudinal metal groove 8, connecting the left and right parts of the metal radiation patch 1. The width W of the longitudinal metal groove 8 is s1 and the length L of the reconfigurable switch device 7 p1 Satisfy the relationship: W s1 <L p1 , the length L of the longitudinal metal groove 8 s1 satisfy:

[0062]

[0063] Among them, ε r1 is the dielectric constant of the first dielectric substrate 2, f2 is the frequency of the resonant mode added by the longitudinal metal groove 8 in the open state of the smart metasurface unit, and c is the speed of light in free space.

[0064] In this embodiment, the length L of the longitudinal metal groove 8 is s1 2.92mm, width W s1 It is 0.2mm.

[0065] In this embodiment, if Figure 4 As shown, the left and right parts of the metal radiation patch 1 are of the same size, and each has an open rectangular ring metal groove 6. The open rectangular ring metal groove 6 is placed symmetrically in the metal radiation patch 1 with its opening facing inward. The width W of the open rectangular ring metal groove 6 in the left and right directions is s2 The width W of the metal radiation patch 1 in the left and right directions p1 Need to meet W p1 >W s2 , the size of the open rectangular ring metal groove 6 needs to meet:

[0066]

[0067] W s2 ≤L s2 ≤1.5×W s2

[0068] Among them, L s2 L is the length of the open rectangular ring metal groove 6 in the vertical direction, subis the length of the opening part of the open rectangular ring metal slot 6, and f4 is the frequency of the resonant mode added by the open rectangular ring metal slot 6 in the closed state of the smart metasurface unit.

[0069] In this embodiment, considering the limitation of the actual processing technology, the minimum copper wire width of the processing technology is W c , then W must be satisfied p1 >W s2 +2×W c .

[0070] In this embodiment, the length L of the open rectangular ring metal groove 6 in the vertical direction is s2 The width W in the left and right directions is 1.1 mm. s2 is 0.8 mm, and the length of the opening is L sub 0.48mm, slot width W sr2 It is 0.1mm.

[0071] In this embodiment, the reflection phase curves of the smart metasurface unit of the broadband smart metasurface of the present invention in the on and off states are as follows: Figure 5 As shown. Figure 5 We can see that the phase curves of the smart metasurface unit in the on and off states have high linearity and good parallelism, showing broadband phase shift characteristics.

[0072] In this embodiment, the reflection phase difference curves of the smart metasurface unit of the broadband smart metasurface of the present invention in the on and off states are as follows: Figure 6 As shown, from Figure 6 We can see that the reflection phase difference of the smart metasurface unit in the on and off states is 180±20°, the phase shift range is 23.8-45.5GHz, and the relative working bandwidth is 62.6%, which verifies that the smart metasurface unit of the broadband smart metasurface of the present invention has broadband characteristics.

[0073] In this embodiment, the reflection amplitude curves of the intelligent metasurface unit of the broadband intelligent metasurface of the present invention in the on and off states are as follows: Figure 7 As shown, from Figure 7 We can see that the unit reflection loss of the smart metasurface unit is less than 3dB in the main working frequency band.

[0074] Figure 8 It is a schematic diagram of the broadband evolution process of the intelligent supersurface unit in the broadband intelligent supersurface of the present invention, wherein the upper row is the structural evolution process, and the lower row is the reflection characteristic curve diagram of the corresponding intelligent supersurface unit in the on and off states.

[0075] In this embodiment, from Figure 8We can see that the smart metasurface unit 1 (referred to as unit 1, and subsequently referred to as unit 2 and unit 3) is a traditional single-mode resonant unit. The unit has only one resonant mode in the switching state, and the phase shift range of the unit is limited.

[0076] Unit 2 adds a longitudinal metal slot 8 on the basis of unit 1. When the reconfigurable switch device 7 is in the on state, the resonance mode of the longitudinal metal slot 8 between adjacent units is excited, so that the phase shift range of unit 2 in the on state is expanded.

[0077] A pair of open rectangular ring metal slots 6 is added to the unit 2 to form the final unit 3, i.e., the smart metasurface unit of the present invention. In the off state, the resonance mode of the open rectangular ring metal slot 6 is excited, so that the phase shift range of the smart metasurface unit in the off state is expanded. The broadband evolution process of the smart metasurface unit verifies that the introduction of a new resonance mode can expand the phase range of the unit.

[0078] Fig. 9 It is the phase difference curve in the on and off states during the broadband evolution of the intelligent supersurface unit in the broadband intelligent supersurface of the present invention.

[0079] In this embodiment, from Fig. 9 We can see that as the number of resonant modes of the smart metasurface unit in the on and off states increases, the number of extreme points of the phase difference curve also increases. The number of resonant modes of the smart metasurface unit in the on state is n=2, the number of resonant modes of the smart metasurface unit in the off state is m=2, and the number of extreme points of the phase difference curve of the smart metasurface unit is N=3. In this way, the mathematical relationship N=n+m-1 between the number of extreme points N of the phase difference curve of the smart metasurface unit and the number of resonant modes of the smart metasurface unit in the on and off states is verified (the number of resonant modes of the smart metasurface unit in the on state is n, and the number of resonant modes of the smart metasurface unit in the off state is m). At the same time, the phase bandwidth of the smart metasurface unit expands with the increase in the number of extreme points of the phase difference curve.

[0080] In this embodiment, a broadband smart metasurface array composed of 16×16 smart metasurface units, i.e., 256 units arranged in an array, is shown in FIG. Fig.10 shown.

[0081] In this embodiment, a feeder line network of a broadband smart metasurface array composed of 16×16 smart metasurface units, i.e., 256 units arranged in an array, is as follows: Fig.11 shown.

[0082] Although the above describes the illustrative specific embodiments of the present invention to facilitate those skilled in the art to understand the present invention, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

Claims

1. A broadband intelligent metasurface, which is composed of a plurality of intelligent metasurface units arranged periodically, wherein the DC control channel of each intelligent metasurface unit is independently designed, and each intelligent metasurface unit includes a five-layer structure, which includes, from top to bottom: The first layer is a metal radiation patch, which receives incident electromagnetic waves in space and radiates them into free space after phase modulation. The second layer structure is a first dielectric substrate, and the metal radiation patch is placed on the first dielectric substrate; The third structure is a metal floor, which is attached below the first dielectric substrate; The fourth layer structure is a second dielectric substrate, which is placed under the metal floor; The fifth layer structure is a metal DC feeding network, which is placed below the second dielectric substrate; The metal radiation patch is divided into left and right parts by a longitudinal metal groove, and the left and right parts are respectively connected to the positive electrode and the negative electrode of the reconfigurable switch device, wherein the part connected to the positive electrode of the reconfigurable switch device passes through the first dielectric substrate, the metal floor and the second dielectric substrate through the positive metal via to be connected to the positive electrode corresponding to the smart metasurface unit in the metal DC feed network, a metal isolation ring is arranged at the positive metal via in the metal floor to isolate the positive metal via from the metal floor, and the part connected to the negative electrode of the reconfigurable switch device passes through the first dielectric substrate, the metal floor and the second dielectric substrate through the negative metal via to be connected to the negative electrode corresponding to the smart metasurface unit in the metal DC feed network, and the negative metal via in the metal floor is connected to the metal floor; It is characterized in that the reconfigurable switch device is placed on the longitudinal metal groove, connecting the left and right parts of the metal radiation patch, and the width of the longitudinal metal groove is W s1 and the length L of the reconfigurable switch device p1 Satisfy the relationship: W s1 <L p1 , the length of the longitudinal metal groove L s1 satisfy: Among them, ε r1 is the dielectric constant of the first dielectric substrate, f2 is the frequency of the resonant mode added by the longitudinal metal groove in the open state of the smart metasurface unit, and c is the speed of light in free space; The left and right parts of the metal radiation patch are of the same size, and each has an open rectangular ring metal groove. The open rectangular ring metal groove is placed symmetrically in the metal radiation patch with its opening facing inward. The width of the open rectangular ring metal groove in the left and right directions is W s2 The width W of the metal radiation patch on the left and right sides p1 Need to meet W p1 >W s2 , the dimensions of the open rectangular ring metal groove need to meet: IN s2 ≤L s2 ≤1.5×H s2 Among them, L s2 L is the length of the open rectangular ring metal groove in the vertical direction, sub is the length of the opening part of the open rectangular ring metal slot, and f4 is the frequency of the resonant mode added by the open rectangular ring metal slot in the closed state of the smart metasurface unit.

2. The broadband smart metasurface according to claim 1, characterized in that: The minimum copper wire width for processing technology is W c , then the width W must be satisfied p1 >W s2 +2×W c .

3. The broadband smart metasurface according to claim 1, characterized in that: The length of the longitudinal metal groove L s1 2.92mm, width W s1 It is 0.2mm.

4. The broadband smart metasurface according to claim 1, characterized in that: The length L of the open rectangular ring metal groove in the vertical direction s2 The width W in the left and right directions is 1.1 mm. s2 is 0.8 mm, and the length of the opening is L sub 0.48mm, slot width W sr2 It is 0.1mm.

5. The broadband smart metasurface according to claim 1, characterized in that: The first dielectric substrate is made of a high-frequency dielectric plate material, whose dielectric constant is 2.2 and whose thickness is 1.016 mm. The second dielectric substrate is made of an FR4 plate material, whose dielectric constant is 4.4 and whose thickness is 0.2 mm.

6. The broadband smart metasurface according to claim 1, characterized in that: The copper foil thickness of the metal radiation patch and the metal DC feeding network is 1oz, and the copper foil thickness of the metal floor is 0.5oz.

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