Wave absorption and protection integrated energy selection metasurface

Abstract

The invention discloses a wave absorption and protection integrated energy selection metasurface, and belongs to the technical field of electromagnetic protection. The invention relates to a dual-band antenna which is composed of a first substrate dielectric substrate, a first metal circuit structure printed on the upper surface of the first substrate dielectric substrate, a second metal circuit structure printed on the lower surface of the first substrate dielectric substrate, a second substrate dielectric substrate and a third metal circuit structure printed on the upper surface of the second substrate dielectric substrate. The energy selection metasurface provided by the invention has energy selectivity in two frequency bands of 1.92 GHz to 2.05 GHz and 4.40 GHz to 4.46 GHz, allows transmission of low-power signals, and reflects or blocks high-power electromagnetic energy at the same time; and the broadband wave-absorbing effect with the wave-absorbing rate higher than 95% is realized in the X wave band. According to the invention, the multi-band energy selection protection function and the broadband high-efficiency wave-absorbing function are integrated at the same time.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic protection technology, and more particularly to an integrated energy-selective metasurface for wave-absorbing protection. Background Art

[0002] As modern electronic information systems accelerate toward intelligence, integration, and miniaturization, device size continues to shrink while the density of electronic components increases significantly, leading to a dramatic increase in the system's sensitivity to changes in surrounding electromagnetic fields, voltage, and current. Experimental studies have shown that electromagnetic pulses can penetrate electronic systems through space radiation or cable coupling. When the coupling energy exceeds the damage threshold of sensitive devices, it can cause device burnout, logical disruption, and even permanent system failure. In particular, intentional or unintentional radiation from high-frequency, high-power microwaves can damage critical electronic components over long distances and without contact, paralyzing the entire system. Ensuring the safe and reliable operation of electronic information systems in complex electromagnetic environments has become a core issue that demands urgent resolution.

[0003] Current protection against strong electromagnetic threats primarily relies on "backdoor" technologies such as filtering, shielding, and grounding. While these methods are easy to implement at the circuit design level, they significantly increase system complexity and design difficulty. For the "front door" channel where electromagnetic energy directly intrudes, existing technologies generally employ the addition of high-power limiters or attenuators at the front end. While these attenuate strong currents, they severely distort normal signals. Frequency selective surfaces (FSS) or bandpass filters, used for out-of-band isolation, operate in fixed frequency bands and lack adaptive capabilities, making them incapable of addressing strong electromagnetic pulse threats within the passband.

[0004] Energy-selective surfaces (ESS), a cutting-edge protection technology based on the principle of field-induced nonlinear impedance transformation, achieve intelligent protection by adaptively adjusting surface impedance properties: maintaining high wave transmission at low power levels and instantaneously switching to a high-impedance shielding state upon strong electromagnetic excitation, with response speeds reaching nanoseconds. However, existing ESS technology still has significant drawbacks, primarily due to its limited functionality and lack of an absorption mechanism (reflective protection is prone to secondary electromagnetic coupling), making it difficult to meet the comprehensive multi-band composite protection and energy absorption requirements of modern electronic devices. Publicly available literature currently does not report any energy-selective surfaces with both multi-band protection and X-band absorption capabilities.

[0005] Therefore, how to propose an integrated energy-selective metasurface for wave absorption and protection, integrating multi-band energy-selective protection with broadband and efficient wave absorption functions, is an urgent problem that needs to be solved by technicians in this field. Summary of the Invention

[0006] In view of this, the present invention provides an integrated energy-selective metasurface for absorbing and protecting waves, which has both multi-band adaptive protection performance and good X-band absorbing performance and a compact structure.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: An integrated energy-selective metasurface with wave absorption and protection, comprising a plurality of periodically arranged metasurface units; The metasurface unit comprises a first substrate dielectric substrate and a second substrate dielectric substrate arranged in parallel at a certain interval; The first substrate dielectric substrate has a first metal circuit structure printed on its upper surface and a second metal circuit structure printed on its lower surface; the second substrate dielectric substrate has a third metal circuit structure printed on its upper surface; The first metal circuit structure, the second metal circuit structure, and the third metal circuit structure are coaxial with the first substrate dielectric base; wherein, the first metal circuit structure and the second metal circuit structure are centrally symmetrical ring structures, the first metal circuit structure includes a plurality of right-angled metal fold line structures connected by resistors, and the second metal circuit structure includes a metal plate having a plurality of hollow fold line structures; the third metal circuit structure includes a first square metal resonant ring structure and a second square metal resonant ring structure, and the first square metal resonant ring structure and the second square metal resonant ring structure are both open C-shaped structures composed of a plurality of metal microstrips, wherein the first square metal resonant ring structure is connected across the two ends of the opening through a diode to form a closed loop, and the second square metal resonant ring structure is connected in parallel with a diode and a capacitor to form a closed loop at both ends of the opening.

[0008] Preferably, the right-angle metal fold line structure includes two fold line units, each of the fold line units includes five straight metal strips connected vertically in sequence, and the two fold line units are connected end to end to form a symmetrical structure.

[0009] Preferably, the second metal circuit structure includes a plurality of hollow units, each of which is a symmetrical structure, including a first right-angle hollow structure, two second right-angle hollow structures, and two straight-line hollow structures; the two second right-angle hollow structures are respectively arranged at both ends of the first right-angle hollow structure, and the other end of each second right-angle hollow structure is connected to one of the straight-line hollow structures; The first right-angled hollow structure is in the shape of a rectangular groove with an open top; the second right-angled hollow structure is in the shape of an upward right-angled folded line; the straight line hollow structure is in the shape of a straight line; The hollow units are vertically connected through the linear hollow structure.

[0010] Preferably, the first square metal resonant ring structure includes a first metal microstrip, a second metal microstrip, a third metal microstrip, a fourth metal microstrip and a fifth metal microstrip; the first metal microstrip is vertically arranged; The second metal microstrip and the fourth metal microstrip are vertically connected to the upper and lower ends of the first metal microstrip respectively; The third metal microstrip is vertically connected to the second metal microstrip downward; the fifth metal microstrip is vertically connected to the fourth metal microstrip upward; and a diode is installed between the third metal microstrip and the fifth metal microstrip.

[0011] Preferably, the first square metal resonant ring structure includes a sixth metal microstrip, a seventh metal microstrip, an eighth metal microstrip, a ninth metal microstrip and a tenth metal microstrip; the sixth metal microstrip is vertically arranged; The seventh metal microstrip and the ninth metal microstrip are vertically connected to the upper and lower ends of the sixth metal microstrip respectively; The eighth metal microstrip is vertically connected to the seventh metal microstrip downward; the tenth metal microstrip is vertically connected to the ninth metal microstrip upward; a diode and a capacitor are connected in parallel between the eighth metal microstrip and the tenth metal microstrip.

[0012] Preferably, the metasurface unit is square.

[0013] The above technical solution demonstrates that, compared to existing technologies, the present invention provides an integrated energy-selective metasurface with absorbing and protective properties. By finely controlling the pattern's size, it achieves energy selectivity within both the L-band and C-band frequency bands, allowing low-power signals to transmit while reflecting or blocking high-power electromagnetic energy. It also achieves broadband absorbing properties with an absorption rate exceeding 95% in the X-band, integrating multi-band energy-selective protection with broadband, high-efficiency absorbing functions. In experimental testing, the present invention demonstrated excellent protection performance exceeding 20dB within the 1.92GHz-2.05GHz and 4.40GHz-4.46GHz operating frequency bands, effectively limiting high-energy electromagnetic wave attacks and preventing damage to electromagnetic equipment. Furthermore, it achieved absorbing performance exceeding 90% in the X-band, effectively reducing RCS. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0015] Figure 1A perspective view of the metasurface unit structure provided by the present invention; Figure 2 Schematic diagram of the first metal circuit structure and the second metal circuit structure provided by the present invention; Figure 3 A schematic diagram of a third metal circuit structure provided by the present invention; Figure 4 This is a diagram showing the low-power incident simulation results of the integrated energy-selective metasurface for wave absorption and protection provided by the present invention; Figure 5 This is a diagram of the high-power incident simulation results of the integrated wave-absorbing and protection energy-selective metasurface provided by the present invention. DETAILED DESCRIPTION

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0017] An embodiment of the present invention discloses an integrated energy-selective metasurface with wave absorption and protection. By sequentially arranging a metal circuit structure, a first substrate dielectric substrate, and a second substrate dielectric substrate to form an electromagnetic protection structure, an electromagnetic protection array is formed. The metasurface can adaptively respond to low-power signals in the C band and strong electromagnetic energy in the full band, achieving the functions of low-power signal transmission and strong electromagnetic energy protection. In addition, it can achieve good wave absorption function in the X band, increasing the protection form of the energy-selective surface, improving the protection performance of the energy-selective surface, and expanding the application scenarios of the energy-selective surface.

[0018] An embodiment of the present invention discloses an integrated energy-selective metasurface for wave absorption and protection, comprising a plurality of periodically arranged metasurface units. metasurface unit.

[0019] refer to Figure 1 The metasurface unit includes a first substrate dielectric substrate and a second substrate dielectric substrate arranged in parallel at a certain interval; the upper surface of the first substrate dielectric substrate is printed with a first metal circuit structure, and the lower surface is printed with a second metal circuit structure; the upper surface of the second substrate dielectric substrate is printed with a third metal circuit structure.

[0020] In this embodiment, each metasurface unit is a square structure, and its side length p satisfies: 8mm≤p≤12mm; the thickness h1 of the first substrate dielectric substrate satisfies: 3mm≤h1≤5mm; the thickness h2 of the second substrate dielectric substrate satisfies: 0.5mm≤h2≤2mm.

[0021] The first substrate dielectric substrate adopts an F4B265TSM dielectric substrate with a dielectric constant of 2.65 and a loss tangent of 0.001; the second substrate dielectric substrate adopts a Rogers RT 5880 dielectric substrate with a dielectric constant of 2.2 and a loss tangent of 0.0009.

[0022] The first metal circuit structure, the second metal circuit structure, and the third metal circuit structure are coaxial with the first substrate dielectric base; wherein, the first metal circuit structure and the second metal circuit structure are centrally symmetrical ring structures, the first metal circuit structure includes a plurality of right-angled metal fold line structures connected by resistors, and the second metal circuit structure includes a metal plate having a plurality of hollow fold line structures; the third metal circuit structure includes a first square metal resonant ring structure and a second square metal resonant ring structure, and the first square metal resonant ring structure and the second square metal resonant ring structure are both C-shaped structures with an opening formed by a plurality of metal microstrips, wherein the first square metal resonant ring structure is connected across the two ends of the opening through a diode to form a closed loop, and the second square metal resonant ring structure is connected in parallel with a diode and a capacitor to form a closed loop at both ends of the opening.

[0023] In this embodiment, the first metal circuit structure is printed on the dielectric substrate using PCB printed circuit board technology. Figure 2 The right-angle metal fold line structure in the first metal circuit structure includes two fold line units, each fold line unit includes five straight metal strips connected vertically in sequence, and the two fold line units are connected end to end to form a symmetrical structure.

[0024] Specifically, the five straight metal strips are respectively a first straight metal strip, a second straight metal strip, a third straight metal strip, a fourth straight metal strip, and a fifth straight metal strip.

[0025] In the first metal circuit structure, the first metal circuit structure is made of copper material with a thickness of 0.017mm or 0.035mm; the metal strip width w1 satisfies 0.1mm≤w1≤0.5mm; the inner edge length l1 of the first straight metal strip satisfies 1mm≤l1≤1.5mm; the inner edge length l2 of the second straight metal strip satisfies 0.4mm≤l2≤0.7mm; the inner edge length l3 of the third straight metal strip satisfies 0.4mm≤l3≤0.7mm; the inner edge length l4 of the fourth straight metal strip satisfies 0.5mm≤l4≤8mm; the inner edge length l5 of the fifth straight metal strip satisfies 0.7mm≤l5≤1mm; the vertical distance between the center of the first metal circuit structure and the inner edge of the first straight metal strip is 1mm≤d1≤1.8mm.

[0026] In the first metal circuit structure, a first gap is provided between adjacent right-angle metal fold line structures for placing a resistor, and a length ga of the first gap satisfies 0.4 mm ≤ ga ≤ 0.6 mm.

[0027] According to one embodiment of the present invention, the width w1 of all metal strips in the first metal circuit structure is 0.4032 mm, the inner edge length l1 of the first straight metal strip is 1.19 mm, the inner edge length l2 of the second straight metal strip is 0.576 mm, the inner edge length l3 of the third straight metal strip is 0.5568 mm, the inner edge length l4 of the fourth straight metal strip is 0.6144 mm, the inner edge length l5 of the fifth straight metal strip is 0.7872 mm, the first gap length ga is 0.5 mm, the distance d1 from the center of the structure to the inner edge of the first straight metal strip is 1.5936 mm, the resistance used for welding is R1, and in this embodiment, R1=100Ω.

[0028] In this embodiment, the second metal circuit structure is printed on the dielectric substrate using an etching process. The second metal circuit structure comprises a plurality of hollow units, each of which is symmetrical, comprising a first right-angle hollow unit, two second right-angle hollow units, and two linear hollow units. The two second right-angle hollow units are disposed at either end of the first right-angle hollow unit, with the other end of each second right-angle hollow unit connected to a linear hollow unit. The first right-angle hollow unit is in the form of a rectangular groove with an open top; the second right-angle hollow unit is in the form of an upward right-angled folded line; and the linear hollow unit is in the form of a straight line. The hollow units are vertically connected by the linear hollow units.

[0029] Similarly, the second metal circuit structure is made of copper material with a thickness of 0.017mm or 0.035mm; in the second metal circuit structure, the width w2 of the hollow structure satisfies 0.1mm≤w2≤0.5mm; the inner edge length l6 of the straight hollow structure satisfies 2mm≤l6≤4mm; the inner edge length l7 of the short side of the first right-angle hollow structure satisfies 0.4mm≤l7≤0.7mm; the inner edge length l8 of the long side of the first right-angle hollow structure satisfies 1.1mm≤l8≤1.6mm; the inner edge length l9 of the short side of the second right-angle hollow structure satisfies 0.5mm≤l9≤0.8mm; the inner edge length l10 of the long side of the second right-angle hollow structure satisfies 1.5mm≤l10≤2mm.

[0030] According to one embodiment of the present invention, the width w2 of all hollow structures in the second metal circuit structure is 0.3885 mm, the inner edge length l6 of the first straight hollow structure is 3.7 mm, the inner edge length l7 of the short side of the first right-angle hollow structure is 0.555 mm, the inner edge length l8 of the long side of the first right-angle hollow structure is 1.4615 mm, the inner edge length l9 of the short side of the second right-angle hollow structure is 0.74 mm, and the inner edge length l10 of the long side of the second right-angle hollow structure is 1.7205 mm.

[0031] The third metal circuit structure is made of copper material with a thickness of 0.017 mm or 0.035 mm.

[0032] like Figure 3 As shown, the first square metal resonant ring structure includes a first metal microstrip, a second metal microstrip, a third metal microstrip, a fourth metal microstrip and a fifth metal microstrip; the first metal microstrip is vertically arranged; the second metal microstrip and the fourth metal microstrip are vertically connected to the upper and lower ends of the first metal microstrip respectively; the third metal microstrip is vertically connected to the second metal microstrip downward; the fifth metal microstrip is vertically connected to the fourth metal microstrip upward; and a diode is installed between the third metal microstrip and the fifth metal microstrip.

[0033] Among them, the length l11 of the first metal microstrip satisfies l11=p, and the width w4 satisfies 0.1mm≤w4≤0.4mm; the length l12 of the second metal microstrip satisfies 0.5mm≤l12≤0.8mm, and the width w5 satisfies 0.1mm≤w5≤0.4mm; the length l13 of the third metal microstrip satisfies l11-l13 2≥0.4mm, width w6 satisfies 3mm≤w6≤5mm; opening gap length gb satisfies gb=l11-l13 2; the fourth metal microstrip has the same size as the third metal microstrip; the fifth metal microstrip has the same size as the second metal microstrip.

[0034] The second square metal resonant ring structure includes a sixth metal microstrip, a seventh metal microstrip, an eighth metal microstrip, a ninth metal microstrip and a tenth metal microstrip; the sixth metal microstrip is vertically arranged; the seventh metal microstrip and the ninth metal microstrip are vertically connected to the upper and lower ends of the sixth metal microstrip respectively; the eighth metal microstrip is vertically connected to the seventh metal microstrip downward; the tenth metal microstrip is vertically connected to the ninth metal microstrip upward; a diode and a capacitor are connected in parallel between the eighth metal microstrip and the tenth metal microstrip.

[0035] Specifically, in the second square metal resonant ring: the length l14 of the sixth metal microstrip satisfies l14=p, and the width w7 satisfies 0.1mm≤w7≤0.4mm; the length l15 of the seventh metal microstrip satisfies 0.5mm≤l15≤0.8mm, and the width w8 satisfies 0.1mm≤w8≤0.4mm; the length l16 of the eighth metal microstrip satisfies l14-l16 2≥0.4mm, width w9 satisfies 3mm≤w9≤5mm; opening gap length gc satisfies gc=l14-l16 2; the ninth metal microstrip has the same size as the eighth metal microstrip; the tenth metal microstrip has the same size as the seventh metal microstrip.

[0036] According to one embodiment of the present invention, the length l11 of the first metal microstrip of the first square metal resonant ring structure is 11.06 mm, the width w4 is 0.2 mm, the length l12 of the second metal microstrip is 0.65 mm, the width w5 is 0.2 mm, the length l13 of the third metal microstrip is 5.33 mm, and the width w6 is 3.6 mm; the length l14 of the sixth metal microstrip of the second square metal resonant ring is 11.06 mm, the width w7 is 0.2 mm, the length l15 of the seventh metal microstrip is 0.55 mm, the width w8 is 0.2 mm, and the length l16 of the eighth metal microstrip is 5.33 mm, and the width w9 is 4.2 mm. The thickness of the metal structure on the surface of all substrates is 0.035mm, the diode model is SMP1330-040LF, the resistance R1 is 100Ω, the capacitance C1 is 0.75pF, the width p of the dielectric substrate of the first substrate is 11.06mm, the F4B265TSM plate is used, and the thickness is 4.3mm; the width p of the dielectric substrate of the second substrate is 11.06mm, the Rogers RT 5880 plate is used, and the thickness is 1mm.

[0037] After the energy-selective metasurface is prepared, the N×M array units in the energy-selective surface are used to perform electromagnetic tests on the incident low-power signal and high-energy electromagnetic wave, respectively, and the expected S11 and S21 curves are obtained.

[0038] Specifically, when a beam of low-power signal passes through an energy selective surface array composed of N×M array units, its incident power is insufficient to excite the diodes on the energy selective surface array. At this time, the energy selective surface is in an unexcited state, and the low-power signal in a specific frequency band can pass through the energy selective surface array with low loss. When a beam of high-energy electromagnetic wave passes through the energy selective surface array composed of N×M array units, its incident power can excite the diodes on the energy selective surface array. At this time, the energy selective surface is in an excited state, and the high-energy electromagnetic wave will be intercepted when passing through the energy selective surface array. The high-energy electromagnetic wave in the X band will be absorbed by this energy selective surface array. After processing at the transmitting and receiving ends of the signal, the S11 and S21 curves of the energy selective surface array under different incident conditions can be obtained.

[0039] Further, refer to Figure 4 and Figure 5 When low-power signals are incident, the energy selective surface array has a low insertion loss wave transmission band near 4.5GHz, and the wave absorption rate in the X-band is greater than 90%; when high-energy electromagnetic waves are incident, the protection efficiency of the energy selective surface array in the range of 1-12GHz is greater than 25dB, and the wave absorption rate in the X-band is greater than 90%. Figure 4 and Figure 5It can be seen that the difference in transmission curves in the wave-transmitting state and the protection state is at least 20dB, which can effectively control the intensity of the transmission signal and has a good wave-absorbing effect in the X-band.

[0040] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0041] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An integrated energy-selective metasurface with wave absorption and protection, characterized in that: comprising a plurality of periodically arranged metasurface units; The metasurface unit comprises a first substrate dielectric substrate and a second substrate dielectric substrate arranged in parallel at a certain interval; The first substrate dielectric substrate has a first metal circuit structure printed on its upper surface and a second metal circuit structure printed on its lower surface; the second substrate dielectric substrate has a third metal circuit structure printed on its upper surface; The first metal circuit structure, the second metal circuit structure, and the third metal circuit structure are coaxial with the first substrate dielectric base; wherein, the first metal circuit structure and the second metal circuit structure are centrally symmetrical ring structures, the first metal circuit structure includes a plurality of right-angled metal fold line structures connected by resistors, and the second metal circuit structure includes a metal plate having a plurality of hollow fold line structures; the third metal circuit structure includes a first square metal resonant ring structure and a second square metal resonant ring structure, and the first square metal resonant ring structure and the second square metal resonant ring structure are both open C-shaped structures composed of a plurality of metal microstrips, wherein the first square metal resonant ring structure is connected across the two ends of the opening through a diode to form a closed loop, and the second square metal resonant ring structure is connected in parallel with a diode and a capacitor to form a closed loop at both ends of the opening.

2. The integrated energy-selective metasurface for wave absorption and protection according to claim 1, characterized in that: The right-angle metal fold line structure includes two fold line units, each of the fold line units includes five straight metal strips connected vertically in sequence, and the two fold line units are connected end to end to form a symmetrical structure.

3. The integrated energy-selective metasurface for wave absorption and protection according to claim 1, characterized in that: The second metal circuit structure includes a plurality of hollow units, each of which is a symmetrical structure, including a first right-angle hollow structure, two second right-angle hollow structures and two straight hollow structures; Two second right-angle hollow structures are respectively arranged at both ends of the first right-angle hollow structure, and the other end of each second right-angle hollow structure is connected to one of the linear hollow structures; The first right-angled hollow structure is in the shape of a rectangular groove with an open top; the second right-angled hollow structure is in the shape of an upward right-angled folded line; the straight line hollow structure is in the shape of a straight line; The hollow units are vertically connected through the linear hollow structure.

4. The integrated energy-selective metasurface for wave absorption and protection according to claim 1, characterized in that: The first square metal resonant ring structure includes a first metal microstrip, a second metal microstrip, a third metal microstrip, a fourth metal microstrip and a fifth metal microstrip; the first metal microstrip is vertically arranged; The second metal microstrip and the fourth metal microstrip are vertically connected to the upper and lower ends of the first metal microstrip respectively; The third metal microstrip is vertically connected to the second metal microstrip downward; the fifth metal microstrip is vertically connected to the fourth metal microstrip upward; and a diode is installed between the third metal microstrip and the fifth metal microstrip.

5. The integrated energy-selective metasurface for wave absorption and protection according to claim 1, characterized in that: The first square metal resonant ring structure includes a sixth metal microstrip, a seventh metal microstrip, an eighth metal microstrip, a ninth metal microstrip and a tenth metal microstrip; the sixth metal microstrip is vertically arranged; The seventh metal microstrip and the ninth metal microstrip are vertically connected to the upper and lower ends of the sixth metal microstrip respectively; The eighth metal microstrip is vertically connected to the seventh metal microstrip downward; the tenth metal microstrip is vertically connected to the ninth metal microstrip upward; a diode and a capacitor are connected in parallel between the eighth metal microstrip and the tenth metal microstrip.

6. The integrated energy-selective metasurface for wave absorption and protection according to claim 1, characterized in that: The metasurface unit is square.

Images