A metasurface unit and a metasurface energy collector having the same

Abstract

The present invention relates to a metasurface unit and a metasurface energy collector having the same, comprising: a metal patch, a plurality of arrow-shaped metal branches and a metal wire; the metal patch is arranged in the center; each of the arrow-shaped metal branches is arranged at the outer edge of the metal patch with the center of the metal patch as the symmetric center, and is connected to the metal patch; each of the metal wires is arranged between two arrow-shaped metal branches, and one end of each metal wire is connected to the metal patch, and the other end is used as an impedance port of the metasurface unit for connecting with the corresponding metal wire of the adjacent metasurface unit through a diode, and an integrated coplanar design. The present invention can be widely used in the field of energy collector technology.

Description

Technical Field

[0001] The present invention relates to the technical field of energy collectors, and in particular to a metasurface unit and a metasurface energy collection system having the same, and in particular to a high-efficiency metasurface unit with polarization insensitivity, wide incident angle, and harmonic suppression, and a metasurface energy collector having the same. Background Art

[0002] RF (radio frequency) energy harvesters can recycle electromagnetic RF energy distributed in the surrounding space, becoming a very promising low-power device power supply solution. RF is a rich source of energy harvesting. It can be emitted from billions of radio transmitters around the world. These transmitters include mobile phones, mobile phone base stations, and TV / radio signal generating base stations. RF signals are received by antennas, and the received energy can be used in RF-DC converters or in pure RF applications. The ability to capture this type of energy helps create new battery-free devices and allows battery-powered devices to be drip-charged wirelessly. In addition to RF energy in the environment, another way is the RF power sent by RF energy transmitting devices specially deployed in special application scenarios. Its high energy density and good directionality can enable wireless power systems to obtain higher energy and are suitable for high-power power supply.

[0003] The receiving antenna is the main component of the RF energy harvester. The most important indicator of the receiving antenna is the collection efficiency, and high collection efficiency is the key to improving the efficiency of the entire receiving system. In order to meet the needs of actual applications, the receiving antenna should also have the following characteristics: First, since the polarization direction and incident direction of the electromagnetic waves in the environment are uncertain, the receiving system is required to have the characteristics of polarization insensitivity and wide incident angle; secondly, nonlinear devices such as rectifier diodes need to be added to the receiving system, and the high-order harmonics generated by the diodes will be radiated secondary, resulting in reduced system efficiency and electromagnetic compatibility problems, so additional harmonic suppression functions are required in the receiving system; thirdly, the energy harvester is equipped with a variety of equipment terminals, so the receiving system is required to have the characteristics of miniaturization, high integration, and power adaptability.

[0004] In order to receive electromagnetic waves of multiple polarizations, the receiving antenna needs to be designed as a circularly polarized antenna; in order to achieve wide incident angle reception, the receiving antenna needs to be designed as an omnidirectional or semi-omnidirectional antenna. Therefore, in the prior art, the multi-polarization and wide incident angle characteristics of the receiving antenna are usually achieved by designing a circularly polarized omnidirectional antenna.

[0005] The main methods for achieving harmonic suppression include: (1) Harmonic suppression is achieved through the design of the rectifier circuit. A low-pass filter is used at the front end of the rectifier circuit to filter out the AC component of the output DC voltage. The design of the low-pass filter usually requires the use of a parallel large capacitor structure, and the matching circuit is designed to achieve impedance matching with the antenna. (2) Design an antenna with harmonic suppression function. By using an open parallel open-circuit stub at the feed structure of a single rectifier antenna to suppress harmonics, the emission coefficient at the harmonic can be suppressed to above -2dB. In principle, the insertion loss caused by the low-pass filter and the performance impact of the antenna are eliminated.

[0006] However, the above implementation method has the following problems:

[0007] (1) Low collection efficiency: The antenna's receiving collection efficiency is around 70%.

[0008] (2) It can only receive electromagnetic waves with specific polarization and incident angle. The receiving antenna is generally a single-polarization narrowband antenna, which has high efficiency only for specific polarization and normal incidence. In other cases, it can hardly receive energy due to polarization mismatch or beam deviation. If it is designed as a circularly polarized receiving antenna, there is a 3dB polarization mismatch for linearly polarized incident electromagnetic waves, which means half of the energy is lost.

[0009] (3) Low integration and high cost. In order to suppress the efficiency drop caused by high-order harmonics, large capacitors and complex harmonic suppression structures need to be connected in parallel between the receiving antenna and the rectifier circuit, which reduces the system integration and increases the cost.

[0010] (4) Large size. In conventional receiving antenna arrays, the unit size is generally the same as the half-wavelength in air corresponding to the resonant frequency, and the distance between adjacent units in the array is generally required to be large to avoid coupling between units. Summary of the invention

[0011] In view of the above problems, the purpose of the present invention is to provide a metasurface unit and a metasurface energy collector having the same, which has the characteristics of polarization insensitivity, wide incident angle, and harmonic suppression, and can adapt to different diodes to achieve power adaptability.

[0012] To achieve the above object, the present invention adopts the following technical solutions:

[0013] In a first aspect, the present invention provides a metasurface unit, comprising:

[0014] Metal patches, a number of arrow-shaped metal branches and metal wires;

[0015] The metal patch is arranged in the center;

[0016] Each of the arrow-shaped metal branches is arranged on the outer edge of the metal patch with the center of the metal patch as the symmetric center, and is connected to the metal patch;

[0017] Each of the metal wires is respectively arranged between the arrow-shaped metal branches, and one end of each of the metal wires is connected to the metal patch, and the other end serves as the impedance port of the metasurface unit for connecting with the corresponding metal wire of the adjacent metasurface unit through a diode, integrating a coplanar design.

[0018] Furthermore, the metal patch is any one of a circular metal patch, a slotted rectangular metal patch or a prism-shaped metal patch.

[0019] Furthermore, when the metal patch is a circular metal patch, the diameter is 5 mm.

[0020] Furthermore, a harmonic suppression structure is also provided on the metal patch, and the harmonic suppression structure is a plurality of slit structures with the center of the metal patch as the symmetry center.

[0021] Furthermore, the slit structure is any one of a T-shaped slot, a U-shaped slot or a Y-shaped slot.

[0022] Furthermore, a gap is reserved between each of the arrow-shaped metal branches, and the width of the gap is 1 mm; the length of each arrow-shaped metal branch from the connection with the outer edge of the metal patch to the tip of the arrow is 5 mm.

[0023] Furthermore, the impedance of the metasurface unit matches the spatial free impedance; and the impedance port of the metasurface unit matches the input impedance of diodes in different power ranges.

[0024] In a second aspect, the present invention provides a metasurface energy collector, comprising:

[0025] Substrate, metasurface unit array, diode rectifier unit, filter and load;

[0026] The metasurface unit array is formed by periodically alternatingly arranging a plurality of metasurface units and metasurface units with grounding through holes disposed on the substrate;

[0027] Each of the metasurface units is connected in parallel or in series, defined as Dc+;

[0028] Each of the metasurface units with grounding through holes is connected to the ground through the grounding through holes provided thereon, and forms an equipotential surface with the ground, which is defined as Dc-;

[0029] The diode rectifier unit includes a plurality of diodes, and the two ends of each diode are respectively connected to a pair of Dc+ and Dc- to achieve rectification of radio frequency energy;

[0030] The rectified AC power energy enters the load through the filter.

[0031] Furthermore, the substrate adopts ROGERS5880 dielectric substrate.

[0032] Furthermore, the filter adopts a class F DC filter.

[0033] The present invention adopts the above technical solution, which has the following advantages:

[0034] (1) High efficiency: The present invention designs a novel metasurface energy collector structure, making the surface impedance of the metasurface equal to the impedance of free space, thereby achieving non-reflection absorption of incident electromagnetic waves, with an absorption efficiency of more than 98%. Compared with the traditional receiving antenna efficiency of only 70%-80%, the receiving efficiency is increased by 20% to more than 95%;

[0035] (2) Multi-polarization: The present invention enhances the effective coupling between metasurface units by designing metasurface units with central symmetric topology and harmonic suppression structure, so that the metasurface units can collect energy incident at various polarization angles, and finally achieve an absorption efficiency of more than 90% under any polarization angle, thus realizing polarization insensitivity.

[0036] (3) Wide incident angle: By designing the artificial electromagnetic surface collector structure and extracting equivalent parameters, the amplitude and phase conditions required for full absorption are simulated and calculated under oblique incidence conditions, further widening the incident angle range: under TE polarization, the absorption efficiency is higher than 85% within the incident angle range of 45°; under TM polarization, the absorption efficiency is higher than 70% within the incident angle range of 60°;

[0037] (4) Harmonic suppression: The present invention integrates the harmonic suppression function directly into the metasurface unit, eliminating the harmonic suppression circuit, solving the electromagnetic compatibility problem in the system, and increasing the total receiving rectification efficiency by 3%-5% to 78%;

[0038] (5) Miniaturization: The 2*2 array size of the metasurface energy harvester is only 1 / 10 of the traditional 2*2 receiving antenna array. If a high dielectric constant substrate is replaced, the size can be further reduced to 1 / 20 of the traditional receiving antenna unit.

[0039] (6) Power adaptability: The array size and diode type can be flexibly adjusted according to the collected power level, making the energy harvester adaptable under different power densities and thus applicable to terminal devices with different power supply requirements;

[0040] Therefore, the present invention can be widely applied in the technical field of energy collectors. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Throughout the accompanying drawings, the same reference numerals are used to represent the same components. In the accompanying drawings:

[0042] Figure 1 It is a slot-type metasurface energy collector unit without harmonic suppression function;

[0043] Figure 2 It is a T-slot type metasurface energy collector unit with harmonic suppression function;

[0044] Figure 3 It is a schematic diagram of the structure of a 2×2 metasurface energy harvester array;

[0045] Figure 4 It is a schematic diagram of the equivalent rectification circuit of the 2×2 metasurface energy harvester;

[0046] Figure 5 is the reflection coefficient and absorptivity of the T-slot metasurface energy collector;

[0047] Figure 6 is the absorption rate of the T-slot metasurface energy harvester at different polarization angles;

[0048] Figure 7 is the absorptivity of the T-slot metasurface energy harvester at different incident angles under TE polarization;

[0049] Figure 8 is the absorptivity of the T-slot metasurface energy harvester at different incident angles under TM polarization;

[0050] Fig. 9 is the reflection coefficient of T-slot aperture-type metasurface energy collector and aperture-slot type metasurface energy collector;

[0051] Fig.10 is the efficiency of T-slot aperture-type metasurface energy collector and aperture-slot type metasurface energy collector;

[0052] The components in the figure are numbered as follows:

[0053] 1. Metal patch; 2. Arrow-shaped metal branches; 3. Metal wire; 4. Harmonic suppression structure. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0055] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0056] First, the related technologies involved in the present invention are briefly introduced:

[0057] WPT: The full name is wireless power transmission, which is a technology that transfers energy with the help of electromagnetic fields or electromagnetic waves.

[0058] RF: The full name is Radio Frequency. Radio frequency refers to the electromagnetic frequency that can be radiated into space, ranging from 300kHz to 300GHz. Radio frequency is radio frequency current, which is the abbreviation of a high-frequency alternating electromagnetic wave.

[0059] AC: Alternating Current. Alternating current is a current whose direction changes periodically over time. The average current in one cycle is zero. Unlike direct current, its direction changes over time, while direct current does not change periodically.

[0060] DC: The full name is Direct Current, which refers to the current whose direction does not change periodically with time, but the current size may not be fixed, resulting in a waveform.

[0061] Example 1

[0062] like Figure 1As shown, this embodiment provides a metasurface unit, which includes: a circular metal patch 1, a plurality of arrow-shaped metal branches 2, and a metal wire 3. The circular metal patch 1 is arranged in the center; each arrow-shaped metal branch 2 is arranged on the outer edge of the circular metal patch 1 with the center of the circular metal patch 1 as the symmetric center; each metal wire 3 is arranged between two arrow-shaped metal branches 2, and one end of each metal wire 3 is connected to the circular metal patch 1, and the other end is used as the impedance port of the metasurface unit to be connected to the corresponding metal wire of the adjacent metasurface unit through a diode, and an integrated coplanar design.

[0063] As a preferred embodiment, the circular metal patch 1 in the metasurface unit can also be replaced with a slotted rectangular or diamond-shaped patch, and the impedance of the metasurface unit needs to be designed to match the free space impedance and the diode impedance at the same time.

[0064] As a preferred embodiment, Figure 2 As shown, a harmonic suppression structure 4 can also be provided on the metasurface unit, and the harmonic suppression structure 4 is a plurality of slit structures provided on the circular metal patch 1 with the center of the circular metal patch 1 as the symmetric center. Among them, the harmonic suppression structure can make the metasurface energy collector show serious impedance mismatch at the second and third harmonics, solve the problem of secondary radiation of high-order harmonics generated by the metasurface unit and the diode, and is used to suppress high-order harmonics without affecting its own absorption characteristics.

[0065] As a preferred embodiment, the slotted structure may be a T-shaped slot, a U-shaped slot, a Y-shaped slot, or the like.

[0066] As a preferred embodiment, a gap is reserved between the two arrow-shaped metal branches 2, and the gap width W is preferably about 1 mm. The gap increases the capacitance effect, facilitates impedance matching with the diode, and also expands the bandwidth.

[0067] As a preferred embodiment, in the metasurface unit, the diameter of the circular metal patch 1 is preferably 5 mm, and the length of each arrow-shaped metal branch 2 from the connection with the outer edge of the circular metal patch 1 to the tip of the arrow is preferably 5 mm.

[0068] As a preferred embodiment, the impedance of the metasurface unit is designed to match the free impedance of space to achieve non-reflection absorption of incident waves. The impedance port of the metasurface unit is designed to match the input impedance of diodes in different power ranges, so that the metasurface energy harvester can be adapted to different input power ranges by replacing diodes. Without changing other parameters, the metasurface energy harvester can effectively collect energy in low, medium and high input power ranges.

[0069] Example 2

[0070] like Figure 3 As shown, this embodiment provides a metasurface energy collector, which includes: a substrate, a metasurface unit array, a diode rectifier unit, a filter and a load. The metasurface unit array is formed by periodically alternating a number of metasurface units and metasurface units with grounding through holes arranged on the substrate; each metasurface unit is connected in parallel, which is defined as Dc+; each metasurface unit with a grounding through hole is connected to the ground through the grounding through hole arranged thereon, and forms an equipotential surface with the ground, which is defined as Dc-; the diode rectifier unit includes a number of diodes, and the two ends of each diode are respectively connected to a pair of Dc+ and Dc-, so as to realize the rectification of radio frequency energy; the rectified AC power enters the load after passing through the filter.

[0071] As a preferred embodiment, the substrate adopts a low-loss ROGERS5880 dielectric substrate. The use of a low-loss dielectric substrate can minimize dielectric loss, thereby improving the efficiency of the metasurface energy collector.

[0072] As a preferred embodiment, the filter adopts a class F DC filter.

[0073] As a preferred embodiment, in this embodiment, each metasurface unit can also be connected in series. The connection method is well known to those skilled in the art and will not be described in detail in the present invention.

[0074] like Figure 4 As shown, Figure 3 The equivalent rectifier circuit of the metasurface energy harvester is shown. The two ends of the diode are connected to Dc+ and Dc-, and all equivalent rectifier unit circuits are connected in parallel through Dc+ to form a parallel equivalent rectifier circuit. Finally, it flows into the Class F DC filter to ensure the smooth output of the DC waveform and isolate the RF power from the load. U is the voltage across the load. In addition, if the number of parallel rectifier units increases, the load resistance will be reduced to achieve higher efficiency.

[0075] Example 3

[0076] This embodiment uses a full-wave simulator CST Figure 3 The metasurface cell shown is simulated. The simulation conditions are: the metasurface cell is truncated in the X and Y directions and excited by the Floquet port in the way that a plane wave normally illuminates the structure (incident in the -Z direction). The simulation of the metasurface cell using periodic boundary conditions effectively simulates an infinite array of metasurfaces.

[0077] like Figure 5 The simulated scattering parameters and absorption rate are shown in Figure 1. The scattering parameters of the metasurface receiver are extracted to calculate the power absorption rate of the metasurface unit. Absorption rate = 1-|S 11 |2 -|S 21 | 2 ,S 11 Represents the reflection coefficient of port 1 when port 2 is matched, S 21 Represents the forward transmission coefficient from port 1 to port 2 when port 2 is matched. The polarization angle and incident angle of the incident electromagnetic wave are changed to obtain the electromagnetic wave absorption efficiency of the metasurface in a complex environment. Figure 6 The absorption rate of the metasurface energy harvester at polarization angles of 0-90° is given. It can be concluded that the metasurface energy harvester can collect energy incident at various polarization angles, and ultimately achieve an absorption efficiency of more than 90% under any polarization angle of incidence, realizing the polarization-insensitive characteristic.

[0078] like Figure 7 and Figure 8 As shown in the figure, the absorption rate of the metasurface energy harvester when the incident angle is 0-60° under TE polarization and TM polarization. Under TE polarization, the absorption efficiency of the metasurface energy harvester is higher than 70% within the range of 45° incident angle; under TM polarization, the absorption efficiency of the metasurface energy harvester is higher than 85% within the range of 60° incident angle. It can be seen that the metasurface energy harvester has a wide-angle incidence characteristic.

[0079] Example 4

[0080] In this embodiment, in order to verify the effect of adding harmonic suppression structure on improving the efficiency of metasurface energy collector, two metasurface energy collectors were designed and manufactured. Figure 3 The energy harvester shown here does not have a harmonic suppression structure (T-slot), and the other is Figure 4 The energy harvester with harmonic suppression structure (T-slot) shown in the figure has the same size and layout of other structures except the harmonic suppression structure.

[0081] like Fig. 9 As shown in the figure, the reflection coefficients of the two energy harvesters are given. It can be seen that the T-slot metasurface energy harvester has a significant inhibitory effect on high-order harmonics. The performance of both are tested under the same external conditions. The actual measurement devices are DC power supply, swept frequency source, and power amplifier. The signal output by the power amplifier is fed into a standard horn antenna, and the energy harvester is placed 1m away from the horn antenna. The power and frequency of the input signal are adjusted using a swept frequency source. A multimeter is used to measure the DC voltage Ur across the load R. The RF energy collection efficiency is calculated using the following formula.

[0082]

[0083] Among them, P in is the total time-averaged power irradiated to the metasurface energy harvester, P ris the total time-averaged power actually received by the metasurface energy harvester, measured by a power meter, P out It is the available time average power received across the resistive load of the rectifier circuit.

[0084] By F riis The formula can be obtained as P in :

[0085]

[0086] Among them, P t is the power fed from the power amplifier to the horn antenna, G t is the actual gain of the transmitting horn antenna, D is the distance between the transmitting and receiving antennas, and A is r is the footprint of a 2x2 metasurface.

[0087] P can be calculated by the following formula out :

[0088]

[0089] Where, R is the load resistance value of the rectifier circuit, V L is the voltage across a single load resistor.

[0090] like Fig.10 As shown in the figure, the efficiency comparison chart of the two metasurface energy harvesters under their best input conditions is given through testing. The efficiency of the energy harvester without harmonic suppression is generally lower than that of the energy harvester with harmonic suppression. Harmonic suppression can increase the system conversion efficiency by 2%-4%. This shows that the solution of integrating the harmonic suppression structure into the energy harvester can improve the conversion efficiency of the system without adding extra cost and size in the process.

[0091] Example 5

[0092] In order to verify the power adaptability of the metasurface energy harvester, this embodiment replaces the diode to adapt to different input power ranges. The diode can usually be selected according to the frequency and input power range, such as SMS-7630 for low-power applications, HSM-2850 for medium-power applications, and HSM-2860 for high power. By introducing matching diodes, the metasurface energy harvester can effectively collect energy within low, medium, and high input power ranges without changing other parameters. That is, the metasurface energy harvester proposed in Example 1 is a power adaptive structure that is suitable for different RF power levels without changing the structural parameters or additional matching networks. Table 1 shows the absorption conversion efficiency of the metasurface energy harvester measured under different diodes. It is proved that the metasurface energy harvester can adapt to different input powers and is very suitable for complex environments with unstable power density.

[0093] Table 1 Energy harvester receiving rectification efficiency under different diodes

[0094]

[0095] Compared with traditional receiving antennas, the metasurface energy harvester provided by the embodiments of the present invention has the following advantages:

[0096] 1. The efficiency of traditional receiving antennas is low, with a receiving efficiency of only 70%-80%. The present invention designs a new metasurface energy collector structure to make the surface impedance of the metasurface equal to the free space impedance, achieving non-reflection absorption of incident electromagnetic waves, and the absorption efficiency can reach more than 98%.

[0097] 2. When the energy collector receives energy, the linearly polarized rectenna requires strict polarization alignment between the transmitting antenna and the receiving antenna in order to achieve high-efficiency absorption, otherwise the efficiency loss caused by polarization mismatch cannot be ignored. Most of the research on metasurface arrays with rectification function is polarization-dependent. The metamaterial energy collector proposed in the present invention can collect energy incident at various polarization angles, and ultimately achieve an absorption efficiency of more than 90% under any polarization angle, with the characteristic of polarization insensitivity.

[0098] 3. In the actual energy collection environment, since the incident electromagnetic waves may be incident at various angles of incidence, how to perfectly receive electromagnetic waves at various angles of incidence is currently an urgent problem to be solved. The traditional receiving antenna has low reception efficiency for electromagnetic waves with non-normal incidence, which reduces the overall efficiency of the entire system. This patent realizes a metasurface energy collector with wide-angle incidence characteristics. Under TE polarization, the absorption efficiency is higher than 85% within the range of 45° incident angle; under TM polarization, the absorption efficiency is higher than 70% within the range of 60° incident angle.

[0099] 4. Existing metasurface-based energy harvesters do not integrate harmonic suppression into the metasurface unit design, so the radiation of diode high-order harmonics will cause a certain efficiency loss. In order to take into account both high-efficiency energy collection and harmonic suppression functions, the present invention innovatively proposes to integrate a harmonic suppression structure on the electromagnetic metasurface, and the energy harvester achieves full absorption at 5.8GHz and full reflection at the second and third harmonics. Ultimately, the overall receiving and rectifying efficiency is improved. Compared with energy harvesters without harmonic suppression, the receiving and rectifying efficiency can be increased by 2%-4%.

[0100] 5. The metasurface energy harvester proposed in the present invention can be adapted to different input power ranges by replacing diodes. Diodes can usually be selected based on frequency and input power range. Without changing other parameters, the metasurface energy harvester can effectively harvest energy in low, medium and high input power ranges. The proposed energy harvester is a power adaptive structure that is applicable to different RF power levels without changing structural parameters or requiring additional matching networks.

[0101] In summary, the present invention has the characteristics of small size, high integration, high efficiency, polarization independence, wide incident angle and power adaptation. It is a new type of intelligent integrated energy collection and nano-power consumption management solution. First, it is very suitable for integration with RFID tags as self-powered electronic tags for warehousing, transportation, tracking and positioning, etc., to achieve one-time loading and permanent use; secondly, it can be integrated with various mobile, low-power industrial Internet of Things sensors to make it a variety of passive sensors; thirdly, it can form a standardized power supply module through on-chip integration and provide a power management interface to facilitate the configuration of any low-power electronic equipment.

[0102] The above embodiments are only used to illustrate the present invention, wherein the structure, connection mode and manufacturing process of each component may be changed. Any equivalent transformations and improvements based on the technical solution of the present invention should not be excluded from the protection scope of the present invention.

Claims

1. A metasurface unit, characterized in that: include: Metal patches, a number of arrow-shaped metal branches and metal wires; The metal patch is arranged in the center; Each of the arrow-shaped metal branches is arranged on the outer edge of the metal patch with the center of the metal patch as the symmetric center, and is connected to the metal patch; Each of the metal wires is respectively arranged between the arrow-shaped metal branches, and one end of each of the metal wires is connected to the metal patch, and the other end is used as an impedance port of the metasurface unit to be connected to the corresponding metal wire of the adjacent metasurface unit through a diode, and an integrated coplanar design is implemented; The metal patch is also provided with a harmonic suppression structure, which is a plurality of slit structures with the center of the metal patch as the symmetric center; The slotted structure is any one of a T-shaped slot, a U-shaped slot or a Y-shaped slot.

2. A metasurface unit as claimed in claim 1, characterized in that: The metal patch is any one of a circular metal patch, a slotted rectangular metal patch or a prism-shaped metal patch.

3. A super surface unit as claimed in claim 2, characterized in that: When the metal patch is a circular metal patch, the diameter is 5 mm.

4. A metasurface unit as claimed in claim 1, characterized in that: A gap is reserved between each of the arrow-shaped metal branches, and the width of the gap is 1 mm; the length of each arrow-shaped metal branch from the connection with the outer edge of the metal patch to the tip of the arrow is 5 mm.

5. A metasurface unit as claimed in claim 1, characterized in that: The impedance of the metasurface unit matches the spatial free impedance; the impedance port of the metasurface unit matches the input impedance of diodes in different power ranges.

6. A metasurface energy collector having a metasurface unit as claimed in any one of claims 1 to 5, characterized in that: include: Substrate, metasurface unit array, diode rectifier unit, filter and load; The metasurface unit array is formed by periodically alternatingly arranging a plurality of metasurface units and metasurface units with grounding through holes disposed on the substrate; Each of the metasurface units is connected in parallel or in series, defined as Dc+; Each of the metasurface units with grounding through holes is connected to the ground through the grounding through holes provided thereon, and forms an equipotential surface with the ground, which is defined as Dc-; The diode rectifier unit includes a plurality of diodes, and the two ends of each diode are respectively connected to a pair of Dc+ and Dc- to achieve rectification of radio frequency energy; The rectified AC power energy enters the load through the filter.

7. A metasurface energy collector according to claim 6, characterized in that: The substrate adopts ROGERS5880 dielectric substrate.

8. A metasurface energy collector according to claim 6, characterized in that: The filter adopts a class F DC filter.

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