An intelligent metasurface

Abstract

The application discloses an intelligent metasurface, relates to the field of electromagnetic cloaking and novel artificial electromagnetic materials, and comprises a reconfigurable metasurface and a self-sensing power supply module connected with the reconfigurable metasurface; the reconfigurable metasurface comprises a plurality of reconfigurable metasurface units arranged periodically; the self-sensing power supply module comprises a plurality of self-sensing power supply units; each reconfigurable metasurface unit comprises, from top to bottom, a first reconfiguration layer, a first dielectric substrate, a metal ring layer, a second dielectric substrate and a second reconfiguration layer; the first reconfiguration layer and the second reconfiguration layer are of the same structure; each self-sensing power supply unit comprises, from top to bottom, a first metal patch, a third dielectric substrate, a second metal patch, a fourth dielectric substrate, a metal gap layer, a fifth dielectric substrate and a rectifier circuit layer. The application can realize autonomous identification and shielding of in-band strong electromagnetic signals without manual intervention and external power supply.

Description

Technical Field

[0001] This invention relates to the fields of electromagnetic stealth and novel artificial electromagnetic materials, and in particular to a smart metasurface. Background Technology

[0002] Electromagnetic stealth materials have wide applications, protecting sensitive electronic equipment from interference signals and absorbing external signals emitted by radar or jammers. Traditional electromagnetic stealth materials, such as ferrites, polycrystalline fibers, and graphite fibers, are bulky, heavy, and expensive. To overcome the shortcomings of traditional materials, many devices based on artificial electromagnetic structures, such as absorbers and diffusers, are widely used as electromagnetic stealth materials to transmit operating signals at specific frequencies while shielding / absorbing signals of other frequencies. However, these electromagnetic stealth devices rely on frequency-selective cancellation of out-of-band electromagnetic signals, making them susceptible to interference signals at the same frequency as the operating device. Therefore, developing intelligent electromagnetic stealth materials that can operate normally within the band (transparent) and autonomously identify and shield strong in-band interference signals holds great promise for effectively protecting electronic systems from both in-band and out-of-band signals. Summary of the Invention

[0003] The purpose of this invention is to provide an intelligent metasurface that can autonomously identify and shield strong electromagnetic signals within a band without human intervention or external power supply.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] This invention provides a smart metasurface, comprising: a reconfigurable metasurface and a self-sensing power supply module connected to the reconfigurable metasurface;

[0006] The reconfigurable metasurface comprises multiple periodically arranged reconfigurable metasurface units; the self-sensing power supply module comprises multiple self-sensing power supply units;

[0007] Each of the reconfigurable metasurface units includes, from top to bottom, a first reconfiguration layer, a first dielectric substrate, a metal ring layer, a second dielectric substrate, and a second reconfiguration layer; the first reconfiguration layer and the second reconfiguration layer have the same structure.

[0008] Each of the self-sensing power supply units includes, from top to bottom, a first metal patch, a third dielectric substrate, a second metal patch, a fourth dielectric substrate, a metal gap layer, a fifth dielectric substrate, and a rectifier circuit layer.

[0009] Optionally, the first reconstruction layer includes a first rectangular annular metal patch, a first rectangular metal patch, four isosceles trapezoidal metal patches, and four PIN diodes;

[0010] The waistlines of the four isosceles trapezoidal metal patches are connected to form a rectangular ring; the first rectangular ring metal patch is disposed outside the four isosceles trapezoidal metal patches; the first rectangular metal patch is disposed inside the four isosceles trapezoidal metal patches; the isosceles trapezoidal metal patches are connected in series with the PIN diode through the first rectangular metal patch.

[0011] Optionally, the metal ring layer includes a second rectangular annular metal patch, a plurality of second rectangular metal patches, and a plurality of first metal pillars;

[0012] One end of the first metal pillar is connected to the first reconstruction layer; the other end of the first metal pillar is connected to one end of the second rectangular metal patch; the first metal pillar is perpendicular to the second rectangular metal patch and the second rectangular annular metal patch respectively; the second rectangular metal patch is disposed inside the second rectangular annular metal patch; the other end of each second rectangular metal patch is connected to the midpoint of one side of the second rectangular annular metal patch; each second rectangular metal patch is perpendicular to the side corresponding to the connected midpoint.

[0013] Optionally, the reconfigurable metasurface unit further includes a second metal pillar; the first metal pillar is used to connect the first reconfiguration layer and the second reconfiguration layer.

[0014] Optionally, the metal gap layer includes a first gap structure and a second gap structure; the first gap structure and the second gap structure have the same image; the first gap structure includes a first horizontal edge, a second horizontal edge, and a vertical edge; the two ends of the vertical edge are respectively connected to the first horizontal edge and the second horizontal edge; the first horizontal edge and the second horizontal edge are parallel; the vertical edge is perpendicular to both the first horizontal edge and the second horizontal edge; the vertical edge of the first gap structure and the vertical edge of the second gap structure are perpendicular to each other.

[0015] Optionally, the rectifier circuit layer includes two identical and orthogonal rectifier circuits.

[0016] Optionally, the first dielectric substrate, the second dielectric substrate, the third dielectric substrate, the fourth dielectric substrate, and the fifth dielectric substrate are all F4B dielectric substrates.

[0017] Optionally, the network between multiple periodically arranged reconfigurable metasurface units is in parallel.

[0018] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0019] The intelligent metasurface provided by this invention includes: a reconfigurable metasurface and a self-sensing power supply module connected to the reconfigurable metasurface; the reconfigurable metasurface includes multiple periodically arranged reconfigurable metasurface units; the self-sensing power supply module includes multiple self-sensing power supply units; each reconfigurable metasurface unit includes, from top to bottom, a first reconfiguration layer, a first dielectric substrate, a metal ring layer, a second dielectric substrate, and a second reconfiguration layer; the first reconfiguration layer and the second reconfiguration layer have the same structure; each self-sensing power supply unit includes, from top to bottom, a first metal patch, a third dielectric substrate, a second metal patch, a fourth dielectric substrate, a metal gap layer, a fifth dielectric substrate, and a rectifier circuit layer. This invention receives strong electromagnetic wave radiation through multiple metal patch layers in the self-sensing power supply module, and couples the energy to the rectifier circuit layer through the metal gap layer. Finally, the rectifier circuit layer outputs a DC voltage to power the reconfigurable metasurface to dynamically control electromagnetic waves, eliminating the need for external power supply. While achieving full transparency to its own signals, it also meets the requirements for intelligent stealth and shielding against strong external interference signals, possessing the ability to adapt to future adaptive stealth. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the intelligent metasurface structure provided by the present invention;

[0022] Figure 2 This is a schematic diagram of a reconfigurable metasurface unit structure;

[0023] Figure 3 This is a schematic diagram of the self-sensing power supply unit structure;

[0024] Figure 4 The S-parameters and gain state diagram of the dual-polarized antenna in the self-sensing power supply unit;

[0025] Figure 5 The far-field radiation pattern of the dual-polarized antenna in the self-sensing power supply unit;

[0026] Figure 6 The output voltage and rectification efficiency status diagram of the rectifier circuit in the self-sensing power supply module;

[0027] Figure 7 Transmittance state diagrams and absorptivity state diagrams for forward-incident reconfigurable metasurfaces without bias voltage and with applied bias voltage.

[0028] Figure 8 The reflectivity state diagram of a reconfigurable metasurface with a back-incident bias voltage.

[0029] Symbol explanation:

[0030] 1-First reconfiguration layer, 2-First dielectric substrate, 3-Metal ring layer, 4-Second dielectric substrate, 5-Second reconfiguration layer, 6-First metal pillar, 7-Second metal pillar, 8-First metal patch, 9-Third dielectric substrate, 10-Second metal patch, 11-Fourth dielectric substrate, 12-Metal gap layer, 13-Fifth dielectric substrate, 14-Rectifier circuit layer, 15-Self-sensing power supply module, 16-Reconfigurable metasurface. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The purpose of this invention is to provide an intelligent metasurface that can autonomously identify and shield strong electromagnetic signals within a band without human intervention or external power supply.

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] like Figure 1 As shown, the present invention provides an intelligent metasurface, comprising: a reconfigurable metasurface 16 and a self-sensing power supply module 15 connected to the reconfigurable metasurface 16; the reconfigurable metasurface 16 includes a plurality of periodically arranged reconfigurable metasurface units; wherein the spacing between adjacent periodically arranged reconfigurable metasurface units is equal; the self-sensing power supply module 15 includes a plurality of self-sensing power supply units; the self-sensing power supply units are multi-layer stacked structures; each of the reconfigurable metasurface units includes, from top to bottom, a first reconfiguration layer 1, a first dielectric substrate 2, a metal ring layer 3, a second dielectric substrate 4, and a second reconfiguration layer 5; the first reconfiguration layer 1 and the second reconfiguration layer 5 have the same structure; each of the self-sensing power supply units includes, from top to bottom, a first metal patch 8, a third dielectric substrate 9, a second metal patch 10, a fourth dielectric substrate 11, a metal gap layer 12, a fifth dielectric substrate 13, and a rectifier circuit layer 14. The first metal patch 8 and the second metal patch 10 are both rectangular patches. The self-sensing power supply module 15 receives strong electromagnetic wave radiation and outputs DC voltage to power the reconfigurable metasurface 16 to dynamically control electromagnetic waves, thereby achieving intelligent stealth and shielding functions.

[0035] like Figure 2 As shown, the reconfigurable metasurface 16 is composed of 20*18 periodic cells, and the power supply network between the cells is in parallel. The bias voltage uniformly regulates the 20*18 periodic cells. The power supply network of the reconfigurable metasurface cells consists of four identical bias loops connected in parallel, specifically composed of a first reconfiguration layer, a metal ring layer, a second reconfiguration layer, a first metal pillar, a second metal pillar, and a PIN diode. The reconfigurable metasurface cells exhibit polarization insensitivity.

[0036] The first reconstruction layer 1 includes a first rectangular annular metal patch, a first rectangular metal patch, four isosceles trapezoidal metal patches, and four PIN diodes. The waistlines of the four isosceles trapezoidal metal patches are arranged adjacently but not in contact. The first rectangular annular metal patch is disposed outside the four isosceles trapezoidal metal patches. The first rectangular metal patch is disposed inside the four isosceles trapezoidal metal patches. The isosceles trapezoidal metal patches are connected in series with the PIN diodes through the first rectangular metal patches. The PIN diodes have two states: non-conducting and conducting, when the forward bias voltage is 0V and 0.7V, respectively. Specifically, the internal equivalent circuits of the PIN diodes are different in the conducting and non-conducting states, thus forming different responses to incident electromagnetic waves.

[0037] The metal ring layer 3 includes a second rectangular annular metal patch, four second rectangular metal patches, and four first metal pillars 6. In this invention, there are multiple second rectangular metal patches and four first metal pillars 6, with four being commonly used. The four second rectangular metal patches are connected to the second rectangular annular metal patch and the four first metal pillars 6, respectively. One end of each first metal pillar 6 is connected to the first reconstruction layer 1; the other end of each first metal pillar 6 is connected to one end of each second rectangular metal patch; the first metal pillars 6 are perpendicular to both the second rectangular metal patch and the second rectangular annular metal patch; the second rectangular metal patches are disposed within the second rectangular annular metal patch; the other end of each second rectangular metal patch is connected to the midpoint of one side of the second rectangular annular metal patch; and each second rectangular metal patch is perpendicular to the side corresponding to the connected midpoint. The first reconstruction layer 1 and the metal ring layer 3 are connected by four centrally symmetrical first metal pillars 6 located 3 mm from the center of the reconfigurable metasurface unit, penetrating the first dielectric layer 2.

[0038] The reconfigurable metasurface unit further includes a second metal pillar 7; the first metal pillar 6 is used to connect the first reconfigurable layer 1 and the second reconfigurable layer 5. The first reconfigurable layer 1 and the second reconfigurable layer 5 are connected by the second metal pillar 7 located at the center of the reconfigurable metasurface unit, which penetrates the first dielectric layer 2 and the second dielectric layer 4. Figure 2 As shown.

[0039] The reconfigurable metasurface unit's metallic structure material is copper. The reconfigurable metasurface unit combines the metal patch structure, the first metal pillar 6, the second metal pillar 7, and the PIN diode in the five-layer structure to achieve a conduction loop. The corresponding unit's power supply network consists of four identical conduction loops connected in parallel, and the units are centrally symmetrical, exhibiting broadband, polarization-insensitive, and angle-insensitive characteristics. The networks between multiple periodically arranged reconfigurable metasurface units are in parallel.

[0040] like Figure 3 As shown, the metal gap layer 12 is formed by hollowing out a copper metal layer to create gaps, including a first gap structure and a second gap structure; the first gap structure and the second gap structure have the same image; the first gap structure includes a first horizontal edge, a second horizontal edge, and a vertical edge; the two ends of the vertical edge are connected to the first horizontal edge and the second horizontal edge, respectively; the first horizontal edge and the second horizontal edge are parallel; the vertical edge is perpendicular to both the first horizontal edge and the second horizontal edge; the vertical edge of the first gap structure and the vertical edge of the second gap structure are perpendicular to each other.

[0041] The first dielectric substrate 2, the second dielectric substrate 4, the third dielectric substrate 9, the fourth dielectric substrate 11 and the fifth dielectric substrate 13 are all F4B dielectric substrates.

[0042] The self-sensing power supply module 15 consists of 2*5 self-sensing power supply units. Each self-sensing power supply unit comprises a dual-polarized patch antenna and a rectifier circuit. The metal slot layer 12 includes two mutually perpendicular H-shaped slot structures. The rectifier circuit layer 14 includes two rectifier circuits of the same shape and perpendicular to each other. One of the rectifier circuits consists of a rectangular metal patch connected in series with a rectifier diode, converting microwave energy into DC voltage, such as... Figure 3 As shown.

[0043] The self-sensing power supply unit's metal structure material is copper. The self-sensing power supply module 15 is highly integrated into the reconfigurable metasurface 16, distributed in a 2*5 array on the top and bottom of the reconfigurable metasurface 16. The output voltage of each self-sensing power supply unit is independent and supplies power to the reconfigurable metasurface 16 in parallel. The positive terminal of the self-sensing power supply module 15 is connected to the positive terminal of the bias network of the reconfigurable metasurface 16; the negative terminal of the self-sensing power supply module 15 is connected to the negative terminal of the bias network of the reconfigurable metasurface 16. Specifically, the output of the rectifier circuit layer 14 in the self-sensing power supply module 15 is positive, and the metal gap layer 12 is negative; the second reconfiguration layer 5 in the reconfigurable metasurface 16 is positive, and the metal ring layer 3 is negative. Figure 4 As shown, the dual-polarized antenna in the self-sensing power supply unit operates in the frequency band of 5.5-7.75 GHz, with an average gain greater than 5.5 dBi. Its far-field radiation pattern is shown below. Figure 5As shown. The rectifier circuit in the self-sensing power supply unit operates in the 4-8GHz frequency band. When the external load is 100Ω, the stable output voltage averages 2.1V, and the rectification efficiency is approximately 40%. Figure 6 As shown.

[0044] Working Principle: When low-power electromagnetic waves are incident on the smart metasurface, the self-sensing power supply module 15 outputs a low voltage, and the reconfigurable metasurface 16 is unbiased, exhibiting the same wave transmission response to forward and backward incident waves. When high-power electromagnetic waves are incident on the smart metasurface, the self-sensing power supply module 15 converts the incident energy into DC voltage, achieving self-powering. When the reconfigurable metasurface 16 is loaded with the output voltage of the self-sensing power supply module 15, the PIN diodes in the first reconfiguration layer 1 and the second reconfiguration layer 5 have different responses, exhibiting different electromagnetic responses to forward and backward incident waves. By default, the metasurface is fully transparent to its own low-power signals. When high-power signals are incident, for forward incident waves, the smart metasurface can absorb the incoming wave, thus adaptively switching from a wave-transmitting state to a wave-absorbing state, achieving intelligent in-band stealth; for backward incident waves, the smart metasurface can effectively reflect the electromagnetic waves, thus adaptively switching from a wave-transmitting state to a reflection state, achieving in-band shielding of the incoming wave.

[0045] When low-power electromagnetic waves are incident on the smart metasurface, the self-sensing power supply module 15 outputs a low voltage, resulting in no bias voltage loading on the reconfigurable metasurface unit. It exhibits wave transmission for both forward (+z direction) and backward (-z direction) electromagnetic wave incidence, with a transmittance greater than 80% and an operating bandwidth of 5.49-7.29 GHz. Figure 7 As shown. When high-power electromagnetic waves are incident on the smart metasurface, the self-sensing power supply module 15 converts the incident energy into DC voltage, achieving self-powering. For forward electromagnetic wave incidentness, the smart metasurface adaptively changes its operating state from a wave-transmitting state to a wave-absorbing state, with an absorption rate greater than 80% and an operating bandwidth of 5.2-7.38 GHz. Figure 7 As shown.

[0046] When the reconfigurable metasurface 16 is loaded with a DC voltage output from the self-sensing power supply module 15, the smart metasurface exhibits reflectivity greater than 50% for incident backward electromagnetic waves, with an operating bandwidth of 4-6.25 GHz. Figure 8 As shown.

[0047] The reconfigurable metasurface 16 provided by this invention operates in the range of 5.5-7.25 GHz. By adjusting the size of the unit, its operating frequency band can be flexibly adjusted and good integrated performance of sensing and dynamic control of electromagnetic waves can be achieved.

[0048] The reconfigurable metasurface 16 is used to dynamically control the transmission, absorption, and reflection of electromagnetic waves from different incident directions. The self-sensing power supply module 15 senses external electromagnetic wave energy and outputs a DC voltage to the reconfigurable metasurface 16. Strong electromagnetic wave radiation is received through multiple metal patch layers in the self-sensing module, and the energy is coupled to the rectifier circuit layer 14 via the metal gap layer 12. Finally, the rectifier circuit outputs a DC voltage to power the reconfigurable metasurface 16 for dynamic control of electromagnetic waves. This invention's technical solution requires no external power supply, achieving full transparency to one's own signals while meeting the requirements for intelligent stealth and shielding against strong external interference signals, and possessing the capability for future adaptive stealth.

[0049] The principles of this invention are divided into two categories: electromagnetic wave dynamic modulation and self-sensing. The electromagnetic wave dynamic modulation principle involves changing the bias voltage on the reconfigurable metasurface unit, thereby altering the equivalent circuit inside the PIN diode. Based on this, the invention can dynamically control the transmission / reflection / absorption states of electromagnetic waves incident from different directions. The sensing principle involves receiving strong electromagnetic wave radiation through the self-sensing power supply module 15 and outputting a DC voltage to power the reconfigurable metasurface 16 for dynamic control of the electromagnetic waves.

[0050] Compared with existing technologies, this invention can achieve adaptive switching between in-band wave transmission and stealth / shielding without the need for external power supply and control modules. It can autonomously sense strong external electromagnetic interference signals to achieve adaptive stealth and shielding. Furthermore, its electromagnetic wave dynamic control capability and self-sensing capability are both broadband, polarization-insensitive, and angle-insensitive.

[0051] Compared with existing electromagnetic protection devices, the bias network design of this invention is ingenious, the unit control is convenient, and the power supply network between units is in parallel, which has the advantages of high stability, strong practicality, and wide applicability.

[0052] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Specific examples are used to illustrate the principles and implementation methods of the invention. The descriptions of the embodiments above are only for the purpose of helping to understand the structure and core ideas of the invention; furthermore, those skilled in the art will recognize that, based on the ideas of the invention, there will be changes in specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the invention.

Claims

1. A smart metasurface, characterized in that, include: A reconfigurable metasurface and a self-sensing power supply module connected to the reconfigurable metasurface; The reconfigurable metasurface comprises multiple periodically arranged reconfigurable metasurface units; the self-sensing power supply module comprises multiple self-sensing power supply units; Each of the reconfigurable metasurface units includes, from top to bottom, a first reconfiguration layer, a first dielectric substrate, a metal ring layer, a second dielectric substrate, and a second reconfiguration layer; the first reconfiguration layer and the second reconfiguration layer have the same structure. Each of the self-sensing power supply units includes, from top to bottom, a first metal patch, a third dielectric substrate, a second metal patch, a fourth dielectric substrate, a metal gap layer, a fifth dielectric substrate, and a rectifier circuit layer; The first reconstruction layer includes a first rectangular annular metal patch, a first rectangular metal patch, four isosceles trapezoidal metal patches, and four PIN diodes; The waistlines of the four isosceles trapezoidal metal patches are arranged adjacently but do not touch, forming a rectangular ring; the first rectangular ring metal patch is disposed outside the four isosceles trapezoidal metal patches; the first rectangular metal patch is disposed inside the four isosceles trapezoidal metal patches; the isosceles trapezoidal metal patches are connected in series with the first rectangular metal patch through the PIN diode; When low-power electromagnetic waves are incident on the smart metasurface, the self-sensing power supply module outputs a low voltage, and the reconfigurable metasurface is unbiased, exhibiting the same wave transmission response to forward and backward incident waves. When high-power electromagnetic waves are incident on the smart metasurface, the self-sensing power supply module converts the incident energy into DC voltage, achieving self-powering. When the reconfigurable metasurface is loaded with the output voltage of the self-sensing power supply module, the PIN diodes in the first and second reconfiguration layers have different responses, exhibiting different electromagnetic responses to forward and backward incident waves. By default, the metasurface is fully transparent to its own low-power signals. When high-power signals are incident, for forward incident waves, the smart metasurface can absorb the incoming wave, thus adaptively switching from a wave-transmitting state to a wave-absorbing state, achieving intelligent in-band stealth. For backward incident waves, the smart metasurface can effectively reflect the electromagnetic waves, thus adaptively switching from a wave-transmitting state to a reflection state, achieving in-band shielding of the incoming wave. The output voltage of each self-sensing power supply unit is independent and supplies power to the reconfigurable metasurface in parallel.

2. The intelligent metasurface according to claim 1, characterized in that, The metal ring layer includes a second rectangular annular metal patch, multiple second rectangular metal patches, and multiple first metal pillars; One end of the first metal pillar is connected to the first reconstruction layer; the other end of the first metal pillar is connected to one end of the second rectangular metal patch; the first metal pillar is perpendicular to the second rectangular metal patch and the second rectangular annular metal patch respectively; the second rectangular metal patch is disposed inside the second rectangular annular metal patch; the other end of each second rectangular metal patch is connected to the midpoint of one side of the second rectangular annular metal patch; each second rectangular metal patch is perpendicular to the side corresponding to the connected midpoint.

3. The intelligent metasurface according to claim 1, characterized in that, The reconfigurable metasurface unit further includes a second metal pillar; the second metal pillar is used to connect the first reconfiguration layer and the second reconfiguration layer.

4. The intelligent metasurface according to claim 1, characterized in that, The metal gap layer includes a first gap structure and a second gap structure; the first gap structure and the second gap structure have the same image; the first gap structure includes a first horizontal side, a second horizontal side, and a vertical side; the two ends of the vertical side are connected to the first horizontal side and the second horizontal side, respectively; the first horizontal side and the second horizontal side are parallel; the vertical side is perpendicular to both the first horizontal side and the second horizontal side; the vertical side of the first gap structure and the vertical side of the second gap structure are perpendicular to each other.

5. The intelligent metasurface according to claim 1, characterized in that, The rectifier circuit layer includes two identical and orthogonal rectifier circuits.

6. The intelligent metasurface according to claim 1, characterized in that, The first dielectric substrate, the second dielectric substrate, the third dielectric substrate, the fourth dielectric substrate, and the fifth dielectric substrate are all F4B dielectric substrates.

7. The intelligent metasurface according to claim 1, characterized in that, The network between multiple periodically arranged reconfigurable metasurface units is in parallel.

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