A reconfigurable power-dependent metasurface for surface waves

Abstract

The application discloses a reconfigurable power-dependent wave-absorbing metasurface for surface waves, comprising an array of electrically tunable units and a surface wave intensity concentration induction control module; the array of electrically tunable units is composed of a plurality of electrically tunable units, and the dispersion characteristics and wave-absorbing efficiency of the transverse magnetic mode surface wave change with the direct current control voltage; the surface wave intensity concentration induction control module is used for sensing the intensity of the transverse magnetic mode surface wave, and outputting a direct current voltage signal to the wave-absorbing array according to the intensity information, so that the wave-absorbing rate is increased with the increase of the surface wave intensity. Compared with the existing power-dependent surface wave absorber, the application has a wider working frequency band and a larger wave-absorbing rate change range. Benefiting from the active control mechanism, the metasurface has a reconfigurable characteristic, which is reflected in the flexible design of the dynamic range and the wave-absorbing rate change range and the real-time switching of the power-dependent characteristic. Thus, the application can be used as a customizable surface wave absorber to shield strong surface wave energy and protect the transmission of useful small signals.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of novel artificial super surface array, and particularly relates to a reconfigurable power-dependent wave-absorbing super surface for surface wave. BACKGROUND

[0002] Surface electromagnetic wave exists widely on the interface of two different media, and its characteristic is to propagate along the interface and the field strength presents exponential decay in the direction perpendicular to the interface. Surface wave and spatial wave are easy to excite each other, and surface wave is the main reason for the mutual coupling between adjacent electromagnetic devices, so people hope to effectively manipulate surface wave. In recent years, researchers have proposed various devices for manipulating surface wave, such as soft and hard surfaces, high impedance surfaces, tensor impedance surfaces, and various surface wave leaky-wave antennas have also been reported; in order to reduce the mutual coupling or interference phenomenon caused by surface wave, people have also developed various surface wave shielding materials.

[0003] Traditional surface wave shielding can be achieved by using high impedance surfaces, corrugated surfaces and other devices, which reflect or scatter electromagnetic waves to other directions on the surface; electromagnetic energy can also be converted into heat by surface wave absorbers, thereby exhibiting surface wave shielding characteristics. In the high-power surface wave shielding scenario, people hope to stop the propagation of high-power surface waves, so as to avoid their penetration into the electronic system through the aperture and interfere with or damage the precision electronic devices, while not wanting useful, low-intensity surface waves to be shielded or absorbed. However, most of the existing surface wave devices have fixed performance and cannot automatically distinguish between useful small signals and unnecessary high-power waves, so they cannot meet the above-mentioned needs.

[0004] Due to the rapid development of nonlinear super surfaces, power-dependent frequency-selective surfaces (PDFSS), energy-selective surfaces (ESS) and surface wave nonlinear absorbers with power-dependent characteristics have begun to appear. PDFSS and ESS are usually used for shielding of spatial electromagnetic waves, which can reflect high-power waves while allowing small signals to pass through. At present, some scholars at home and abroad have carried out research on nonlinear absorbers for surface waves, but the working bandwidth of these power-dependent absorbers is very narrow, and some devices can only work at a single frequency point, and the range of their absorption rate change with surface wave power is relatively narrow; they are mostly passive working mechanisms and do not have reconfigurable characteristics. The performance deficiencies greatly limit the application of these devices. SUMMARY

[0005] According to the deficiencies of the prior art, the application provides a reconfigurable power-dependent wave-absorbing metasurface for surface waves, which has a wider working frequency band and a larger wave-absorbing rate variation range compared with the prior power-dependent surface wave absorber.

[0006] The application is implemented according to the following technical scheme:

[0007] A reconfigurable power-dependent wave-absorbing metasurface for surface waves comprises:

[0008] An electrically adjustable unit array is composed of a plurality of electrically adjustable units, and the dispersion characteristics and wave-absorbing efficiency of the transverse magnetic mode surface wave vary with the direct current control voltage.

[0009] A surface wave intensity concentration induction control module is used for sensing the intensity of the transverse magnetic mode surface wave and outputting a direct current voltage signal to the wave-absorbing array according to the intensity information, so that the wave-absorbing rate is increased with the increase of the surface wave intensity.

[0010] In some embodiments, the electrically adjustable unit array is periodically arranged by a plurality of electrically adjustable units; the electrically adjustable unit is a three-layer metal and two-layer dielectric structure, which comprises, from top to bottom, a top metal, a first dielectric layer, an intermediate metal, a second dielectric layer and a bottom metal.

[0011] In some embodiments, the top metal comprises four metal patches and a PIN diode between the four metal patches; wherein the four metal patches are numbered as metal patch T1, metal patch T2, metal patch T3 and metal patch T4; the intermediate metal comprises a cross-shaped metal wire and two square metal patches; and the bottom metal is an overall covering metal.

[0012] In some embodiments, the four metal patches are uniformly spaced in two rows and two columns, and a PIN diode is arranged between each two adjacent metal patches; the anodes of the four PIN diodes are connected to the metal patch T2 and the metal patch T4, and the cathodes of the four PIN diodes are connected to the metal patch T1 and the metal patch T3; the metal patches are provided with a protruding portion at the connection position of the PIN diode; and the two square metal patches are a center-symmetrical structure with the intersection point of the cross-shaped metal wire as the center, and the two square metal patches have an overlapping portion at the intersection point.

[0013] In some embodiments, the electrically adjustable unit further comprises two metal through holes and two metal blind holes, the metal through holes connect the metal patch T1 and the metal patch T3 to the bottom metal, and the metal blind holes connect the metal patch T2 and the metal patch T4 to the square metal patch of the intermediate metal.

[0014] In some embodiments, when a plurality of electrically adjustable units form an array, the metal patches and metal wires on the middle layer metal of all electrically adjustable units are connected as a whole and connected to the metal patches T2 and T4 on the top layer metal through metal blind holes; the bottom layer metal of all electrically adjustable units is connected as a whole and connected to the metal patches T1 and T3 on the top layer metal through metal vias; the PIN diodes on the top layer metal surface of all electrically adjustable units are connected in parallel, and the dispersion characteristics and wave absorption efficiency of the electrically adjustable unit array are regulated by changing the positive bias working state of the PIN diodes by applying a direct current bias voltage between the middle layer metal and the bottom layer metal.

[0015] In some embodiments, the surface wave intensity concentrated induction control module is a three-layer metal and two-layer dielectric structure, including a top layer metal, a first dielectric layer, a middle layer metal, a second dielectric layer, and a bottom layer metal placed in order from top to bottom.

[0016] In some embodiments, the top layer metal is a square metal patch, the middle layer metal is a metal ground, and the bottom layer metal is a microstrip line and a radio frequency detection circuit; a metal via connects the center of the square metal patch of the top layer metal and one end of the bottom layer microstrip line, and the other end of the microstrip line is connected to the input end of the radio frequency detection circuit; the metal ground has a circular hole with a diameter larger than the aperture of the metal via, so that the metal via does not contact the middle layer metal; the function of the square metal patch of the top layer metal is to couple a small amount of transverse magnetic mode surface wave energy and conduct the energy to the bottom layer radio frequency detection circuit through the metal via.

[0017] In some embodiments, the radio frequency detection circuit includes a radio frequency detection integrated circuit chip on the bottom layer metal and a peripheral circuit composed of a plurality of resistors and capacitors, which is used to receive electromagnetic wave energy from the square metal patch of the top layer metal, output a corresponding direct current voltage according to the intensity of the electromagnetic wave, and the higher the intensity, the greater the direct current voltage; the output end of the radio frequency detection circuit is connected to the middle layer metal of the electrically adjustable unit array, i.e., connected to the anode of the PIN diode of the top layer metal; by changing the resistance value in the radio frequency detection circuit, the power dynamic range of the super surface can be set; by changing the compensation voltage Vos in the radio frequency detection circuit, the wave absorption rate change range can be regulated in real time; by setting the power supply voltage V CC Directly turn off the power-dependent wave absorption function, so that the super surface presents fixed and unchanged low-loss performance.

[0018] Compared with the prior art, the present application has the following advantages:

[0019] (1) The existing power-dependent surface wave absorber has a narrow range of wave absorption rate variation and a narrow working frequency, and even only a point frequency. The reconfigurable power-dependent wave absorption super surface for surface electromagnetic waves in the application has a maximum wave absorption rate adjustment range of 19.4%-92.7% with the change of transverse magnetic mode surface wave power, and can realize 30%-80% wave absorption rate adjustment in a frequency band with a relative bandwidth of 12%, which is much better than the existing power-dependent surface wave absorber design.

[0020] (2) The existing power-dependent surface wave absorber is mostly passive working mechanism and does not have reconfigurable characteristics, so the performance is fixed and the application scene is limited. The application realizes power-dependent control by using an active concentrated induction control method, so the input power dynamic range, wave absorption rate control range and the switch of the whole system of the super surface can be customized by changing the active circuit parameters, and thus various surface wave shielding scene requirements can be met.

[0021] (3) The application can be prepared by using mature printed circuit board processing technology and component surface mounting technology, and has the advantages of small processing difficulty and low cost. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings, which are part of this application, serve to further understand the application, and the illustrative embodiments of the application and their descriptions serve to explain the application, but do not constitute undue limitations on the application. Obviously, the drawings described below are only some embodiments, and other drawings can be obtained from these drawings without creative labor for those skilled in the art.

[0023] In the drawings:

[0024] Figure 1 It is a top surface structure schematic diagram of a reconfigurable power-dependent wave absorption super surface for surface waves of the application.

[0025] Fig. 2(a) is a three-dimensional structure schematic diagram of an electrically adjustable unit in an embodiment of the application.

[0026] Fig. 2(b) is a top layer metal structure schematic diagram of an electrically adjustable unit in an embodiment of the application.

[0027] Fig. 2(c) is a middle layer metal structure schematic diagram of an electrically adjustable unit in an embodiment of the application.

[0028] Fig. 3(a) is a three-dimensional structure schematic diagram of a surface wave intensity concentrated induction control module in an embodiment of the application.

[0029] Fig. 3(b) is a schematic diagram of a radio frequency detection circuit in an embodiment of the application.

[0030] Figure 4(a) is a front view of a reconfigurable power-dependent metamaterial absorber according to an embodiment of the present application.

[0031] Figure 4(b) is a back view of a reconfigurable power-dependent metamaterial absorber according to an embodiment of the present application.

[0032] Figure 4(c) is a photo of a radio frequency detection circuit according to an embodiment of the present application.

[0033] Figure 4(d) is a photo of a metamaterial absorber testing system according to an embodiment of the present application.

[0034] Figure 5(a) is a reflection coefficient test result of an electrically tunable unit array under direct current voltage control according to an embodiment of the present application.

[0035] Figure 5(b) is a transmission coefficient test result of an electrically tunable unit array under direct current voltage control according to an embodiment of the present application.

[0036] Figure 5(c) is a power-dependent absorption rate test result of an electrically tunable unit array under direct current voltage control according to an embodiment of the present application.

[0037] Figure 6(a) is a direct current voltage test result of a PIN diode under different intensity electromagnetic wave incidence conditions at 5.35 GHz when the radio frequency detection circuit output is connected to the positive electrode of the unit array PIN diode according to an embodiment of the present application.

[0038] Figure 6(b) is a reflection coefficient test result of a reconfigurable power-dependent metamaterial absorber under different surface wave power incidence conditions according to an embodiment of the present application.

[0039] Figure 6(c) is a transmission coefficient test result of a reconfigurable power-dependent metamaterial absorber under different surface wave power incidence conditions according to an embodiment of the present application.

[0040] Figure 6(d) is a power-dependent absorption rate test result of a metamaterial absorber according to an embodiment of the present application.

[0041] Figure 6(e) is a test result of the absorption rate of a metamaterial absorber at 5.16 GHz as the incident wave power continuously increases according to an embodiment of the present application.

[0042] Figure legend: 1, electrically tunable unit array; 2, electrically tunable unit; 21, metal patch; 22, first dielectric layer; 23, cross-shaped metal wire; 24, square metal patch; 25, second dielectric layer; 26, bottom layer metal; 27, PIN diode; 211, metal through hole; 212, metal blind hole; 3, surface wave intensity concentration induction control module; 31, square metal patch; 32, metal ground; 33, microstrip line; 34, radio frequency detection circuit; 35, radio frequency detection integrated circuit chip; 311, metal through hole.

[0043] It should be noted that the drawings and the detailed description are not intended to limit the scope of the inventive concept in any way, but rather to illustrate the inventive concept to a person skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments will be described clearly and completely below with reference to the drawings in the embodiments of the present application. The following embodiments are used to illustrate the present application, but are not used to limit the scope of the present application.

[0045] In the description of the present application, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0046] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0047] As shown in Figure 1 A reconfigurable power-dependent wave-absorbing metasurface for surface waves includes an array of electrically tunable units 1 and a surface wave intensity concentration sensing control module 3. The array of electrically tunable units 1 is composed of several electrically tunable units 2, and the wave-absorbing efficiency for transverse magnetic (TM) mode surface waves varies with the direct current control voltage. The surface wave intensity concentration sensing control module 3 is used to sense the intensity of the transverse magnetic (TM) mode surface waves, and output a direct current voltage signal to the wave-absorbing array according to the intensity information, so that the wave-absorbing rate increases with the increase of the surface wave intensity. Compared with the existing power-dependent surface wave absorber, the present application has a wider working frequency band and a larger wave-absorbing rate variation range. Thanks to the active control mechanism, the dynamic range of the sensing module and the wave-absorbing rate variation range can be flexibly adjusted, and the wave-absorbing function can also be directly turned off as needed, so that the metasurface presents a fixed and unchanging low-loss performance. Therefore, it can be used as a customizable surface wave absorber to shield strong surface wave energy while protecting the transmission of useful small signals.

[0048] A preferred embodiment of the array of electrically tunable units in the above embodiment is given as follows:

[0049] The electrically adjustable unit array in the application is composed of 3 rows and 6 columns of electrically adjustable units. As shown in FIG. 2(a), the electrically adjustable unit 2 is a three-layer metal and two-layer dielectric structure, and the top layer metal, the first dielectric layer 22, the middle layer metal, the second dielectric layer 25 and the bottom layer metal 26 are sequentially stacked from top to bottom.

[0050] As shown in FIG. 2(b), the top layer metal includes four metal patches 21 and PIN diodes 27 between the four metal patches; the four metal patches are numbered as metal patch T1, metal patch T2, metal patch T3 and metal patch T4 respectively.

[0051] It should be noted that the four metal patches 21 are uniformly arranged in two rows and two columns, and one PIN diode 27 is arranged between each two adjacent metal patches 21. The anodes of the four PIN diodes 27 are connected to the metal patch T2 and the metal patch T4, the cathodes of the four PIN diodes 27 are connected to the metal patch T1 and the metal patch T3, and the metal patch 21 is provided with a protruding part at the connection position with the PIN diode 27.

[0052] As shown in FIG. 2(c), the middle layer metal includes a cross-shaped metal wire 23 and two square metal patches 24.

[0053] It should be noted that the two square metal patches 24 are a center-symmetrical structure with the intersection point of the cross-shaped metal wire 23 as the center, and the two square metal patches 24 have an overlapping part at the intersection point.

[0054] The bottom layer metal is an overall covering metal.

[0055] The electrically adjustable unit further includes two metal through holes 211 and two metal blind holes 212, the metal through holes 211 connect the metal patch T1 and the metal patch T3 to the bottom layer metal respectively, and the metal blind holes 212 connect the metal patch T2 and the metal patch T4 to the square metal patches of the middle layer metal respectively.

[0056] Further scheme: continuing to refer to Figure 2(a) 、 2(b) , 2(c), the structural parameters of the electrically adjustable unit are: a=2.9mm, b=0.2mm, g=0.8mm, p1=15mm, w1=10.5mm, w2=2.1mm, h1=1.5mm, h2=0.5mm. The materials of the first dielectric layer 22 and the second dielectric layer 25 are Rogers RO4003C, the relative dielectric constant is 3.55, and the loss tangent is 0.0027. The PIN diode is selected as SMP1321 of Skyworks.

[0057] Continuing to refer to Figure 1As shown, when a plurality of electrically adjustable units form an array, the metal patches and metal wires on the middle layer metal of all electrically adjustable units are connected as a whole and connected to the metal patch T2 and the metal patch T4 on the top layer metal through the metal blind hole; the bottom layer metal of all electrically adjustable units is connected as a whole and connected to the metal patch T1 and the metal patch T3 on the top layer metal through the metal via hole; the PIN diodes on the top layer metal surface of all electrically adjustable units are connected in parallel, the positive bias working state of the PIN diode is changed by applying a direct current bias voltage between the middle layer metal and the bottom layer metal, so as to control the dispersion characteristics and the wave absorption efficiency of the electrically adjustable unit array.

[0058] The following gives a preferred embodiment of the surface wave intensity concentration induction control module of the above-mentioned embodiment:

[0059] The surface wave intensity concentration induction control module in the reconfigurable power-dependent wave-absorbing metasurface is used for sensing the incident surface wave power intensity and outputting a direct current voltage signal varying with the surface wave power to control the wave absorption performance of the electrically adjustable unit array. The three-dimensional structure diagram of the surface wave intensity concentration induction control module is shown in FIG. 3(a), which adopts the same printed circuit board structure as the electrically adjustable unit array and contains a top layer metal, a first dielectric layer 22, a middle layer metal, a second dielectric layer 25 and a bottom layer metal placed in turn from top to bottom.

[0060] The top layer metal is a square metal patch 31, the middle layer metal is a metal ground 32, and the bottom layer metal is a microstrip line 33 and a radio frequency detection circuit 34. The metal via hole 311 connects the center of the square metal patch 31 and one end of the bottom layer microstrip line 33, and the other end of the microstrip line 33 is connected to the input end of the radio frequency detection circuit 34. There is a circular hole on the metal ground 32 with a diameter larger than the aperture of the metal via hole, so the metal via hole is not in contact with it. The square metal patch 31 couples a small amount of TM mode surface wave energy, which is conducted to the bottom layer radio frequency detection circuit 34 through the metal via hole 311.

[0061] The structure of the radio frequency detection circuit is shown in FIG. 3(b), which contains a radio frequency detector 35 and a peripheral circuit for receiving electromagnetic wave energy from the top layer patch, outputting a corresponding direct current voltage according to the electromagnetic wave intensity, and the higher the intensity, the greater the direct current voltage. The output end of the radio frequency detection circuit is connected to the middle layer metal of the electrically adjustable unit array, i.e. connected to the anode of the PIN diode on the top layer.

[0062] In this embodiment, the radio frequency detector is an LTC5535 RF detection chip of Linear Technology Company, and the peripheral circuit parameters are C1=39pF, C2=0.1uF, C3=100pF, R1=20kΩ, R2=10kΩ, and the power supply voltage V CC of the detection chip is 4.5V.

[0063] In order to verify the performance of the reconfigurable power-dependent wave-absorbing metasurface in the present application, a reconfigurable power-dependent wave-absorbing metasurface sample is processed in the present embodiment, which includes 3x6 electrically adjustable units and one surface wave intensity concentration induction control module. The front and back photos of the sample are shown in FIG. 4(a) and FIG. 4(b), and the photo of the underlying radio frequency detection circuit is shown in FIG. 4(c). The sample is tested in a standard rectangular waveguide system, and the photo of the system is shown in FIG. 4(d). The main equipment used in the method is a vector network analyzer (VNA) and a standard rectangular waveguide (WR187); one waveguide port is connected to port 1 of the vector network analyzer (VNA) through an isolator, and the other waveguide port is connected to port 2 of the VNA; the sample is placed on the bottom surface of the standard rectangular waveguide, and the surface wave intensity concentration induction control module faces the side of port 2 of the VNA. At this time, only the signal from port 2 to port 1 can be transmitted, and the reverse signal is cut off by the isolator. The direct current bias line of the metasurface sample is led out of the waveguide and connected to a direct current stabilized power supply.

[0064] The reasons for using this test method are as follows: ① The electric field of the main mode TE10 mode in the standard rectangular waveguide is perpendicular to the waveguide bottom plane, which is very similar to the electric field of the TM mode surface wave, which can excite the TM mode surface wave on the metasurface sample; ② The test is carried out in a closed waveguide, which is conducive to quantitatively controlling the incident wave power, and the reflection and transmission signal coefficients can be accurately measured, and then the formula A = 1- |Γ| 2 -|T| 2 The wave-absorbing efficiency is calculated. Here Γ is the reflection coefficient, i.e. the S22 result of the VNA, and T is the transmission coefficient, i.e. the S12 result of the VNA.

[0065] It should be noted that in order to place the test sample in the WR187 waveguide for quantitative testing, the sample processed in the present embodiment only includes 3x6 electrically adjustable units and one surface wave intensity concentration induction control module. In fact, the application scenario of the reconfigurable power-dependent wave-absorbing metasurface in the present application is surface wave shielding on a large-area metal plane, so the metasurface can include a larger number of electrically adjustable units, which share one or more intensity concentration induction modules.

[0066] The embodiment first tests the wave-absorbing performance of the electrically tunable unit array under the control of the direct current bias voltage. The PIN diode is directly connected to the direct current stabilized power supply, the output power of the VNA is fixed at -5 dBm, and the obtained reflection coefficient and transmission coefficient results are shown in FIG. 5(a) and (b), and the calculated wave-absorbing rate is shown in FIG. 5(c). It can be seen that, in the frequency range of 4.93 GHz to 5.61 GHz, when the voltage changes from 0 V to 0.60 V, the wave-absorbing rate of the TM mode surface wave gradually increases. When the voltage is 0 V, the wave-absorbing efficiency of the electrically tunable unit array in this frequency band is less than 30%; when the voltage is 0.60 V, the wave-absorbing efficiency in this frequency range is more than 80%. The lowest wave-absorbing efficiency occurs at 5.33 GHz, which is 13.3%, and the highest wave-absorbing efficiency occurs near 5.18 GHz, which reaches 95.4%.

[0067] Subsequently, the anode of the PIN diode of the unit array is connected to the output end of the radio frequency detection circuit, and the performance of the super surface sample is observed by changing the output power of the VNA. When the frequency is 5.35 GHz, the direct current voltage across the PIN diode under different intensity electromagnetic wave incidence is shown in FIG. 6(a). It can be observed that, when the incident power changes from 5 dBm to 20 dBm, the voltage across the diode gradually increases. When the incident power is 5 dBm, the voltage is about 0.21 V, and when the incident power is 20 dBm, the voltage is about 0.62 V. This voltage change reflects that when the surface wave power changes, the state of the PIN diode changes accordingly, indicating that the performance of the unit array will also change.

[0068] The obtained reflection coefficient and transmission coefficient results are shown in FIG. 6(b) and (c). It can be seen that, during the change of the incident power from 5 dBm to 20 dBm, the actual reflection coefficient of the tested sample in the target frequency band is below -10 dB; at 5.16 GHz, the transmission coefficient of the incident power of 5 dBm is -0.93 dB, and the transmission coefficient of the incident power of 20 dBm is -13.02 dB, having a wide power tuning range. The calculated wave-absorbing rate is shown in FIG. 6(d), and it can be seen that the wave-absorbing rate gradually increases with the increase of the incident wave power. In the frequency band of 4.93 GHz to 5.56 GHz (relative bandwidth 12.0%), when the incident power is 5 dBm, the wave-absorbing rate is less than 30%; as the incident power gradually increases to 20 dBm, the wave-absorbing rate continuously increases to more than 80%. FIG. 6(e) shows the largest power-dependent wave-absorbing rate adjustment range that occurs at 5.16 GHz, which gradually increases from 19.4% to 92.7%, showing excellent wave-absorbing performance with the change of the incident wave power.

[0069] Compared with the existing power-dependent surface wave absorber, the active power-dependent mechanism of the present application has the advantage that the performance of the metasurface can be reconfigured by flexible design or real-time regulation of the radio frequency detection circuit of the intensity sensing module, which will be discussed in detail as follows:

[0070] First, the sensitivity of the sensing module to the incident wave power is changed by changing the resistance ratio of the two peripheral resistors in the detection circuit, and then the incident wave dynamic range is designed. In this embodiment, the peripheral resistors R1 = 20kΩ and R2 = 10kΩ, and the amplifier gain inside the detection circuit can be calculated as 3 according to G = 1 + R1 / R2. If the gain is increased, the sensitivity will be improved, and the curve shown in Figure 6(a) will become steep, and the metasurface dynamic range will also become narrow.

[0071] Second, the initial output voltage of the sensing module is changed in real time by changing the voltage of the compensation pin V os of the detection circuit, and then the lower limit of the absorptivity range is adjusted. If V os is less than 0.2V, the initial output voltage is 0.2V, if V os is greater than 0.2V, V start = 0.5·V os ·Gain. In this embodiment, V os is grounded, i.e. 0V, so the minimum output voltage of the module is 0.21V, and the power-dependent absorptivity regulation range is the largest. If V os is increased, the initial output voltage of the module will be raised, and the lower limit of the absorptivity will also be raised. When V os = 0.4V, the module will output 0.6V, at this time the metasurface will always exhibit the strongest absorptivity performance regardless of the incident wave power, and its performance is shown in the 20dBm curve in Figure 6(c).

[0072] Third, if the power supply V CC of the build-up circuit is turned off, the sensing module will stop working, and the voltage across the PIN diode in the electrically adjustable unit array will be 0V, so the metasurface degenerates into a linear working state and exhibits the weakest absorptivity performance, as shown in the 0V curve in Figure 5(c).

[0073] In summary, the present application proposes a reconfigurable power-dependent absorptive metasurface for surface waves, which includes an electrically adjustable unit array and a surface wave intensity concentration sensing control module. The surface wave power intensity is collected by using a concentration sensing control method, and the absorptivity control of the system is realized. This is a flexible and adjustable surface electromagnetic wave absorption scheme, which has the advantages of wide frequency band, large absorptivity change range, low cost, etc. At the same time, the dynamic range, absorptivity regulation range and the switch of the whole system can be customized, so it can meet the needs of various surface wave shielding scenarios.

[0074] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the application can be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0075] In addition, those skilled in the art will appreciate that the features described herein with respect to some embodiments can be combined in different embodiments, while still falling within the scope of the application and forming different embodiments. For example, in the above embodiments, those skilled in the art can use the features in a combined manner according to the known technical solutions and the technical problems to be solved by the present application.

[0076] The above description is only the preferred embodiment of the present application, not any form of limitation to the present application, although the present application has been disclosed as above with the preferred embodiment, however, not to define the present application, any skilled in the art of the patent can make some changes or modifications as equivalent embodiments with the above prompted technical content without departing from the scope of the technical solutions of the present application, but as long as it does not depart from the content of the technical solutions of the present application, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present application, still belongs to the scope of the present application.

Claims

1. A reconfigurable power-dependent metasurface for surface waves, characterized in that, include: An electrically adjustable unit array, consisting of several electrically adjustable units, exhibits dispersion characteristics and absorption efficiency of transverse magnetic mode surface waves that vary with DC control voltage. The surface wave intensity centralized sensing control module is used to sense the surface wave intensity of the transverse magnetic mode and output a DC voltage signal to the absorbing array according to the intensity information, so that the absorption rate increases with the increase of surface wave intensity. The electrically adjustable unit array is composed of multiple electrically adjustable units arranged in a periodic manner; The electrically adjustable unit has a three-layer metal and two-layer dielectric structure, comprising a top metal layer, a first dielectric layer, a middle metal layer, a second dielectric layer, and a bottom metal layer stacked from top to bottom; The top metal layer comprises four metal patches and PIN diodes located between the four metal patches; The four metal patches are numbered T1, T2, T3, and T4 respectively. The intermediate metal layer consists of cross-shaped metal conductors and two square metal patches; The bottom metal is a full-surface metal cover; When several electrically adjustable units form an array, the metal patches and metal wires on the middle layer metal of all electrically adjustable units are connected as a whole, and connected to the metal patches T2 and T4 on the top layer metal through metal blind holes; All electrically adjustable units are connected as a whole at the bottom metal level and connected to the metal patch T1 and metal patch T3 on the top metal level through metal through holes; The PIN diodes on the top metal surface of all electrically tunable units are connected in parallel. By applying a DC bias voltage between the intermediate metal layer and the bottom metal layer to change the forward bias state of the PIN diodes, the dispersion characteristics and absorption efficiency of the electrically tunable unit array can be controlled.

2. The reconfigurable power-dependent absorbing metasurface for surface waves according to claim 1, characterized in that: The four metal patches are arranged in two rows and two columns at equal intervals. A PIN diode is set between each two adjacent metal patches. The anodes of the four PIN diodes are connected to metal patches T2 and T4, and the cathodes of the four PIN diodes are connected to metal patches T1 and T3. The metal patches have protruding portions at the connection points with the PIN diodes. The two square metal patches are symmetrical about the intersection of the cross-shaped metal wires, and the two square metal patches overlap at the intersection.

3. The reconfigurable power-dependent absorbing metasurface for surface waves according to claim 1, characterized in that: The electrically adjustable unit also includes two metal through holes and two metal blind holes. The metal through holes connect metal patch T1 and metal patch T3 to the bottom metal, respectively, and the metal blind holes connect metal patch T2 and metal patch T4 to the square metal patch of the middle layer metal, respectively.

4. The reconfigurable power-dependent absorbing metasurface for surface waves according to claim 1, characterized in that: The surface wave intensity centralized sensing and control module is a three-layer metal and two-layer dielectric structure, comprising a top metal layer, a first dielectric layer, a middle metal layer, a second dielectric layer, and a bottom metal layer stacked from top to bottom.

5. The reconfigurable power-dependent metamaterial absorber for surface waves of claim 4, wherein: the top layer metal is a square metal patch, the middle layer metal is a metal ground, and the bottom layer metal is a microstrip line and a radio frequency (RF) detection circuit; a metal via connects the center of the square metal patch of the top layer metal and one end of the microstrip line, and the other end of the microstrip line is connected to an input end of the RF detection circuit; a circular aperture with a diameter larger than that of the metal via is formed in the metal ground, so that the metal via is not in contact with the middle layer metal; the square metal patch of the top layer metal is configured to couple a small amount of transverse magnetic (TM) mode surface wave energy and transmit the energy to the RF detection circuit through the metal via.

6. The reconfigurable power-dependent metamaterial absorber for surface waves of claim 5, wherein: the RF detection circuit includes an RF detection integrated circuit chip and a peripheral circuit composed of resistors and capacitors, which are configured to receive electromagnetic wave energy from the square metal patch of the top layer metal, output a corresponding direct current (DC) voltage according to the intensity of the electromagnetic wave, and increase the DC voltage as the intensity of the electromagnetic wave increases; an output end of the RF detection circuit is connected to the middle layer metal of the electrically tunable unit array, i.e., connected to the anode of the PIN diode of the top layer metal; by changing the resistance value of the RF detection circuit, the power dynamic range of the metamaterial absorber can be set; by changing the offset voltage Vos of the RF detection circuit, the absorption rate change range can be adjusted in real time. By setting the power supply voltage V of the radio frequency detection circuit CC Directly turn off the power-dependent wave absorption function, so that the metasurface presents fixed and unchanging low-loss performance.

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