2bit programmable metasurface unit and 2bit programmable metasurface

Abstract

The invention provides a 2-bit programmable metasurface unit and a 2-bit programmable metasurface. The 2-bit programmable metasurface unit comprises a metal structure layer, a first dielectric layer and a metal ground layer which are sequentially distributed from top to bottom, the metal structure layer comprises a metal frame, a first square metal patch, a second square metal patch, a third square metal patch, a first-stage tube and a second-stage tube, the first square metal patch and the third square metal patch are respectively positioned on two opposite sides of the second square metal patch; the metal frame is connected with the metal ground layer through the first metalized through hole; the first square metal patch and the second square metal patch are connected through a first diode, and the second square metal patch and the third square metal patch are connected through a second diode; the first square metal patch is used as a first positive electrode connecting point and is used for connecting a first positive electrode; the third square metal patch is used as a second positive electrode connecting point and is used for connecting a second positive electrode; the second square metal patch is connected to the metal ground layer. According to the technical scheme, the metal frame is arranged and is connected to the ground, so that the coupling effect of adjacent units is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic metasurfaces, and in particular to a 2-bit programmable metasurface unit and a 2-bit programmable metasurface. Background Art

[0002] Electromagnetic metasurfaces are artificial two-dimensional materials composed of subwavelength unit arrays, usually with complex metal structures. By adjusting the size, shape, spacing, and arrangement of these units, specific electromagnetic properties can be imparted to them. These microstructures can achieve precise local control of the phase, amplitude, polarization, and direction of electromagnetic waves, thereby enabling fine manipulation of the wavefront. The emergence of the generalized Snell's law has shifted the research of metasurface technology towards more precise control of the reflection and transmission of incident waves. "Coded metamaterials", "digital metamaterials", and "programmable metamaterials" characterize the reflection characteristics of metasurface units through binary coding, greatly simplifying the design and manufacturing processes. Usually, the state of metasurface units is dynamically changed by electronic, mechanical, or other means, realizing the ability to regulate electromagnetic properties in real time. This dynamic characteristic makes metasurface technology exhibit greater flexibility and adaptability, capable of meeting the needs of future diverse application scenarios. Thanks to these innovations, metasurface technology shows great versatility and adaptability in electromagnetic wave control. Metasurface-based applications include superlenses, invisibility cloaks, specific absorbers, vortex beam generators, and holographic imaging technologies, etc. These applications not only confirm the great potential of metasurfaces in the field of electromagnetic wave control but also indicate their broad application prospects in future communication, imaging, and sensing fields.

[0003] With the rapid development of digital coding technology and the increasing demand for dynamic electromagnetic control, the research and development of 2-bit programmable metasurface units are gradually becoming a key direction in the field of metasurface technology. Compared with traditional fixed-coded or 1-bit programmable metasurface units, 2-bit programmable metasurface units can achieve the regulation of electromagnetic waves with a higher degree of freedom, supporting four different state codings. Through precise state switching, 2-bit programmable metasurface units can provide richer control capabilities in terms of reflection phase, amplitude, and polarization characteristics, thus meeting more complex wavefront regulation requirements. In addition, this programming unit also has a high degree of dynamic adjustment ability and can achieve real-time response by combining electronic, photonic, or mechanical driving means. This ability not only makes the application of metasurfaces more adaptable in specific scenarios, such as multi-mode communication, tunable optical devices, and intelligent sensing systems, but also can significantly improve the overall efficiency and intelligence level of the device.

[0004] Therefore, it is very important to study 2-bit programmable metasurface units to continuously improve their performance. Summary of the Invention

[0005] The present invention provides a 2-bit programmable metasurface unit and a 2-bit programmable metasurface to solve the problem that the performance of existing 2-bit programmable metasurface units is not good enough.

[0006] To solve the above technical problems, the present invention is implemented through the following technical solutions:

[0007] According to a first aspect of the present invention, there is provided a 2-bit programmable metasurface unit, which includes: a basic structure, and the basic structure includes, from top to bottom in sequence: a metal structure layer, a first dielectric layer, and a metal ground layer;

[0008] The metal structure layer includes: a metal frame and, within the metal frame, a first square metal patch, a second square metal patch, a third square metal patch, a first diode, and a second diode; wherein, the first square metal patch and the third square metal patch are respectively located on opposite sides of the second square metal patch;

[0009] The metal frame is connected to the metal ground layer through at least one first metallized via, and the first metallized via penetrates from the metal frame at least to the metal ground layer;

[0010] The first square metal patch is connected to the second square metal patch through the first diode, and the second square metal patch is connected to the third square metal patch through the second diode;

[0011] The first square metal patch serves as a first positive connection point for connecting a first positive electrode; the third square metal patch serves as a second positive connection point for connecting a second positive electrode; and the second square metal patch is connected to the metal ground layer.

[0012] Optionally, the metal frame is a square metal frame; the center of the second square metal patch is located at the center of the square metal frame; and the centers of the first square metal patch and the third square metal patch are located on the line connecting the midpoints of two opposite sides of the square metal frame.

[0013] Optionally, the metal structure layer further includes: a first inductor, a second inductor, a third inductor, a first pad, a second pad, and a third pad within the metal frame;

[0014] The first inductor and the first pad are sequentially connected between the first square metal patch and the first positive electrode;

[0015] The second inductor and the second pad are sequentially connected between the third square metal patch and the second positive electrode;

[0016] The second square metal patch is connected to the metal ground plane, specifically: the second square metal patch is connected to the metal ground plane through the third inductor and the third pad in sequence.

[0017] Optionally, the first pad is connected to the first positive electrode through a second metallized via hole, the second metallized via hole penetrates from the metal structure layer to the bottom of the basic structure, and is isolated from the metal ground plane;

[0018] The second pad is connected to the second positive electrode through a third metallized via hole, the third metallized via hole penetrates from the metal structure layer to the bottom of the basic structure, and is isolated from the metal ground plane;

[0019] The third pad is connected to the metal ground plane through a fourth metallized via hole, the fourth metallized via hole penetrates from the metal structure layer to the metal ground plane;

[0020] The first metallized via hole penetrates from the metal frame to the bottom of the basic structure.

[0021] Optionally, circular isolation grooves are provided between the second metallized via hole and the third metallized via hole and the metal ground plane.

[0022] Optionally, the side length of the square metal frame is any value between 16.4 mm and 16.6 mm;

[0023] The length of the longitudinal side of the first square metal patch is any value between 2.33 mm and 2.35 mm, and the length of its transverse side is any value between 1.8 mm and 1.9 mm;

[0024] The length of the longitudinal side of the second square metal patch is any value between 8.2 mm and 8.4 mm, and the length of its transverse side is any value between 9.1 mm and 9.2 mm;

[0025] The length of the longitudinal side of the third square metal patch is any value between 2.31 mm and 2.33 mm, and the length of its transverse side is any value between 2.16 mm and 2.17 mm;

[0026] Wherein, the longitudinal side refers to the side along the arrangement direction of the first square metal patch, the second square metal patch, and the third square metal patch.

[0027] Optionally, the first pad, the second pad, and the third pad are square metal patches;

[0028] The side length of the square metal patch is 1 mm.

[0029] Optionally, the first pad is connected to the second metallized via by a first metal wire, and the length of the first metal wire is any value between 2.43 mm and 2.45 mm;

[0030] The second pad is connected to the third metallized via by a second metal wire, and the length of the second metal wire is any value between 2.25 mm and 2.27 mm;

[0031] The third pad is connected to the fourth metallized via by a third metal wire, and the length of the third metal wire is any value between 0.48 mm and 0.5 mm.

[0032] Optionally, the basic structure further includes: an adhesive layer and a second dielectric layer; the adhesive layer is located under the metal ground layer, the second dielectric layer is located under the adhesive layer, and a preset distance is provided between the adhesive layer and the second dielectric layer.

[0033] Optionally, the dielectric constant of the first dielectric layer is any value between 2.6 and 3, its tangent of loss angle is any value between 0.001 and 0.0025, and its thickness is any value between 2.8 mm and 3.1 mm;

[0034] The dielectric constant of the adhesive layer is any value between 4.1 and 4.5, its tangent of loss angle is any value between 0.01 and 0.03, and its thickness is any value between 0.05 mm and 0.15 mm;

[0035] The dielectric constant of the second dielectric layer is any value between 4.1 and 4.5, its tangent of loss angle is any value between 0.01 and 0.03, and its thickness is any value between 0.4 mm and 0.6 mm.

[0036] According to a second aspect of the present invention, there is provided a 2-bit programmable metasurface, which includes at least one 2-bit programmable metasurface unit described in any one of the above.

[0037] For the 2-bit programmable metasurface unit and the 2-bit programmable metasurface provided by the present invention, by providing a metal frame at the edge of the metal structure layer, and connecting the metal frame to the metal ground layer through the first metallized via, most of the electric field or current can be returned to the ground, thereby reducing the coupling effect between adjacent units.

[0038] In an optional solution of the present invention, an inductor is provided between the first square metal patch, the second square metal patch, the third square metal patch and the first positive connection point, the ground connection point, and the second positive connection point, reducing the influence of electromagnetic waves on the DC loop.

[0039] In an optional solution of the present invention, the first positive electrode connection point, the second positive electrode connection point, and the ground connection point are led out through metallized through-holes, and an external voltage can be applied to the metallized through-holes through a control circuit, which facilitates circuit design.

[0040] In an optional scheme of the present invention, an adhesive layer and a second dielectric layer are also provided at the bottom of the metal layer, and a preset distance is separated between the adhesive layer and the second dielectric layer, and the circuit layer can be arranged between the two; the first metallized through hole, the second metallized through hole, and the third metallized through hole penetrate to the bottom of the basic structure, that is, these metallized through holes also penetrate the distance between the adhesive layer and the second dielectric layer, and the circuit layer can be connected to these metallized through holes in this space, which facilitates the design of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0042] Figure 1 A side view of a 2-bit programmable metasurface unit according to an embodiment of the present invention;

[0043] Figure 2 A top view of a 2-bit programmable metasurface unit according to an embodiment of the present invention;

[0044] Figure 3 A bottom view of a 2-bit programmable metasurface unit according to an embodiment of the present invention;

[0045] Figure 4 A top view of a 2-bit programmable metasurface unit according to another embodiment of the present invention;

[0046] Figure 5 A side view of a 2-bit programmable metasurface unit according to another embodiment of the present invention;

[0047] Figure 6 A schematic diagram showing the relationship between phase and frequency of a 2-bit programmable metasurface unit according to an example of the present invention;

[0048] Figure 7 A schematic diagram showing the relationship between the reflection amplitude and frequency of a 2-bit programmable metasurface unit according to an example of the present invention;

[0049] Description of reference numerals:

[0050] 1-Metal structure layer;

[0051] 111 - Metal frame;

[0052] 121 - First square metal patch;

[0053] 122 - Second square metal patch;

[0054] 123 - Third square metal patch;

[0055] 131 - First diode;

[0056] 132 - Second diode;

[0057] 141 - First metallized via;

[0058] 142 - Second metallized via;

[0059] 143 - Third metallized via;

[0060] 144 - Fourth metallized via;

[0061] 151 - First metal wire;

[0062] 152 - Second metal wire;

[0063] 153 - Third metal wire;

[0064] 161 - First inductor;

[0065] 162 - Second inductor;

[0066] 163 - Third inductor;

[0067] 171 - First pad;

[0068] 172 - Second pad;

[0069] 173 - Third pad;

[0070] 2 - First dielectric layer;

[0071] 3 - Metal ground layer;

[0072] 4 - Adhesive layer;

[0073] 5 - Second dielectric layer. Detailed implementation manners

[0074] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0075] In the description of the specification of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "upper part", "lower part", "upper end", "lower end", "lower surface", "upper surface", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0076] In the description of the specification of the present invention, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0077] In the description of the present invention, the meaning of "a plurality" is a plurality, such as two, three, four, etc., unless otherwise specifically defined.

[0078] In the description of the specification of the present invention, unless otherwise clearly specified and defined, terms such as "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or communication with each other; it can be directly connected, or indirectly connected through an intermediate medium, and can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present invention can be understood according to specific circumstances.

[0079] The technical solution of the present invention will be described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

[0080] Please refer to Figures 1 - 3 , in one embodiment, a 2-bit programmable metasurface unit is provided, which includes: a basic structure, and the basic structure includes a metal structure layer 1, a first dielectric layer 2, and a metal ground layer 3 that are distributed in sequence from top to bottom, as Figure 1 shown. Among them, the metal structure layer 1 includes: a metal frame 111 and a first square metal patch 121, a second square metal patch 122, a third square metal patch 123, a first diode 131, and a second diode 132 located within the metal frame 111.

[0081] Specifically, the metal frame is provided with at least one first metallized via 141, and the first metallized via penetrates from the metal frame to at least the metal ground layer, that is, the metal frame is connected to the metal ground layer through the first metallized via, so that most of the electric fields or currents can return to the ground, reducing the coupling effect between adjacent metasurface units. The first square metal patch 121 and the third square metal patch 123 are respectively located on opposite sides of the second square metal patch 122, as Figure 2 shown. The first square metal patch 121 is connected to the second square metal patch 122 through a first diode 131, and the second square metal patch 122 is connected to the third square metal patch 123 through a second diode 132. The first square metal patch 121 serves as the first positive connection point for connecting the first positive electrode; the third square metal patch 123 serves as the second positive connection point for connecting the second positive electrode; the second square metal patch 122 is connected to the metal ground layer; and four states of "00", "01", "10", and "11" with a phase difference of about 90° are realized by controlling the on-off of the two diodes. Among them, "00" corresponds to the first diode being off and the second diode being off, "01" corresponds to the first diode being off and the second diode being on, "10" corresponds to the first diode being on and the second diode being off, and "11" corresponds to the first diode being on and the second diode being on.

[0082] Please continue to refer to Figure 1 , in this embodiment, the metal frame 111 is taken as a square metal frame. The center of the second square metal patch 122 is located at the center of the square metal frame 111; the centers of the first square metal patch 121 and the third square metal patch 123 are located on the line connecting the midpoints of two opposite sides of the square metal frame 111.

[0083] Please continue to refer to Figure 1 , in this embodiment, the number of the first metallized vias 141 is taken as four, and the four first metallized vias 141 are respectively located at the four corners of the metal frame 111, and the shape of the first metallized via 141 is taken as a 1 / 4 circle. In different embodiments, the number of the first metallized vias 141 is not necessarily four and can be freely set according to needs.

[0084] Please continue to refer to Figure 3 , in this embodiment, the first metallized via 141 penetrates from the metal frame to the bottom of the basic structure. In different embodiments, the first metallized via 141 can also only penetrate to the metal ground layer as long as it can be connected to the metal ground layer.

[0085] As an implementation manner, please continue to refer to Figures 1 - 3, the first square metal patch 121 is connected to the first positive electrode through the second metallized via 142. The second metallized via 142 penetrates from the metal structure layer to the bottom of the basic structure and is isolated from the metal ground layer, that is, not connected to the metal ground layer. The third square metal patch 123 is connected to the second positive electrode through the third metallized via 143. The third metallized via 143 penetrates from the metal structure layer to the bottom of the basic structure and is isolated from the metal ground layer, that is, not connected to the metal ground layer. The second square metal patch 122 is connected to the metal ground layer 3 through the fourth metallized via 144. The fourth metallized via 144 penetrates from the metal structure layer to the metal ground layer 3.

[0086] Preferably, circular isolation grooves are provided between the second metallized via and the third metallized via and the metal ground layer, with better isolation effect and more stable performance.

[0087] The square metal patch and the metallized via can be connected by metal wires. Specifically, between the first square metal patch 121 and the second metallized via 142, between the third square metal patch 123 and the third metallized via 143, and between the second square metal patch 122 and the fourth metallized via 144 are connected by the first metal wire 151, the second metal wire 152, and the third metal wire 153 respectively, as Figure 2 shown.

[0088] Please refer to Figure 4 , in another embodiment, an inductor is also provided between the square metal patch and the electrode. The setting of the inductor can reduce the influence of electromagnetic waves on the DC circuit. Specifically, the metal structure layer further includes: a first inductor 161, a second inductor 162, a third inductor 163 and a first pad 171, a second pad 172, a third pad 173 located within the metal frame 111. The first inductor 161 and the first pad 171 are sequentially connected between the first square metal patch and the first positive electrode; the second inductor 162 and the second pad 172 are sequentially connected between the third square metal patch and the second positive electrode; the second square metal patch is connected to the metal ground layer. Specifically, the second square metal patch is sequentially connected to the metal ground layer through the third inductor 163 and the third pad 173. For the remaining structure, please refer to Figures 1 - 3 the embodiment shown, which will not be elaborated here.

[0089] and Figures 1 - 3Similar to the embodiments, the first pad 171 is connected to the first positive electrode through the second metallized via 142. The second metallized via 142 penetrates from the metal structure layer to the bottom of the basic structure and is isolated from the metal ground layer, that is, it is not connected to the metal ground layer. The second pad 172 is connected to the second positive electrode through the third metallized via 143. The third metallized via 143 penetrates from the metal structure layer to the bottom of the basic structure and is isolated from the metal ground layer, that is, it is not connected to the metal ground layer. The third pad 173 is connected to the metal ground layer 3 through the fourth metallized via 144. The fourth metallized via 144 penetrates from the metal structure layer to the metal ground layer 3.

[0090] Please refer to Figure 5 , in another embodiment, the basic structure further includes: an adhesive layer 4 and a second dielectric layer 5; the adhesive layer 4 is located below the metal ground layer 3, the second dielectric layer 5 is located below the adhesive layer, and a preset distance is provided between the adhesive layer and the second dielectric layer. The circuit can be disposed between the adhesive layer and the second dielectric layer.

[0091] The remaining structure is similar to that of the Figures 1 - 3 embodiment shown and will not be described in detail here. Among them, the first metallized via 141, the second metallized via 142, and the third metallized via 143 penetrate to the bottom of the basic structure, that is, from the metal structure layer to the bottom of the second dielectric layer, as Figure 5 shown. The circuit is disposed between the adhesive layer and the second dielectric layer, and the above-mentioned metallized vias penetrate here, and the circuit can be directly connected to the metallized vias.

[0092] As an example, the side length P of the square metal frame in the above embodiment is any value between 16.4 mm and 16.6 mm; the length of the longitudinal side W1 of the first square metal patch 121 is any value between 2.33 mm and 2.35 mm, and the length of its transverse side L1 is any value between 1.8 mm and 1.9 mm. The length of the longitudinal side W2 of the second square metal patch 122 is any value between 8.2 mm and 8.4 mm, and the length of its transverse side L2 is any value between 9.1 mm and 9.2 mm. The length of the longitudinal side W3 of the third square metal patch 123 is any value between 2.31 mm and 2.33 mm, and the length of its transverse side L3 is any value between 2.16 mm and 2.17 mm. Among them, the longitudinal side W refers to the side along the arrangement direction of the first square metal patch, the second square metal patch, and the third square metal patch, as Figure 2 shown.

[0093] Preferably, the first pad, the second pad, and the third pad are square metal patches, as Figure 4 shown; the side length of the square metal patch is 1 mm.

[0094] The length of the first metal wire 151 between the first pad and the second metallized via is any value between 2.43 mm and 2.45 mm; the length of the second metal wire between the second pad and the third metallized via is any value between 2.25 mm and 2.27 mm; the length of the third metal wire between the third pad and the fourth metallized via is any value between 0.48 mm and 0.5 mm.

[0095] Performing simulation on the metasurface unit with the above dimensions set, the simulation results as shown in Figure 6 , Figure 7 can be obtained. From Figure 6 the simulation results, it can be seen that at the 5.8 GHz frequency point, the phase values are 29.9°, -58.9°, 117.1°, -149.5° respectively, meeting the performance requirements of a 90-degree phase difference. From Figure 7 the simulation results, it can be seen that the reflection amplitude response is greater than -2 dB, indicating that the above 2-bit programmable metasurface unit can better achieve the electromagnetic wave manipulation ability and has a high reflection efficiency at 5.8 GHz. 5.8 GHz is one of the common frequency bands for protocols such as Wi-Fi and Bluetooth, and is particularly suitable for applications of short-distance and high-speed communication, with a wide range of applications.

[0096] The dimensions in the above examples are the preferred dimensions at the 5.8 GHz frequency point. When the frequency band is different, the dimensions are also different, and different settings can be made according to needs.

[0097] As an example, in the above embodiment, the dielectric constant of the first dielectric layer is any value between 2.6 and 3, its tangent of loss angle is any value between 0.001 and 0.0025, and its thickness h1 is any value between 2.8 mm and 3.1 mm. The dielectric constant of the adhesive layer is any value between 4.1 and 4.5, its tangent of loss angle is any value between 0.01 and 0.03, and its thickness h2 is any value between 0.05 mm and 0.15 mm. The dielectric constant of the second dielectric layer is any value between 4.1 and 4.5, its tangent of loss angle is any value between 0.01 and 0.03, and its thickness h3 is any value between 0.4 mm and 0.6 mm.

[0098] As an example, in the above embodiment, the first diode 131 and the second diode 132 adopt PIN diodes.

[0099] Preferably, the models of the first diode 131 and the second diode 132 are: SMP1320-040LF. When they are conducting, they can be regarded as a 0.75 ohm resistor and a 0.08 nH package inductor in series. When they are off, they can be regarded as a 0.2 pF capacitor, a 7.5 ohm resistor and a 0.1 nH package inductor in series.

[0100] Preferably, the models of the first inductor, the second inductor, and the third inductor are: LQW15AN12NG80, the inductance value is 12 nH, and the tolerance is ±2%.

[0101] In the description of this specification, the descriptions with reference to terms such as "an implementation manner", "an embodiment", "specific implementation process", "an example", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0102] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A 2-bit programmable metasurface unit, characterized in that: include: A basic structure, wherein the basic structure includes, in order from top to bottom, a metal structure layer, a first dielectric layer, and a metal ground layer; The metal structure layer includes: a metal frame and a first square metal patch, a second square metal patch, a third rectangular metal patch, a first diode, and a second diode located in the metal frame; wherein the first square metal patch and the third rectangular metal patch are located on opposite sides of the second square metal patch respectively; The metal frame is connected to the metal layer through at least one first metallized through hole, and the first metallized through hole penetrates from the metal frame to at least the metal layer; The first square metal patch and the second square metal patch are connected via the first diode, and the second square metal patch and the third square metal patch are connected via the second diode; The first square metal patch is used as a first positive electrode connection point for connecting to a first positive electrode; the third square metal patch is used as a second positive electrode connection point for connecting to a second positive electrode; and the second square metal patch is connected to the metal ground layer.

2. The 2-bit programmable metasurface unit according to claim 1, characterized in that: The metal frame is a square metal frame; the center of the second square metal patch is located at the center of the square metal frame; the centers of the first square metal patch and the third square metal patch are located on the line connecting the midpoints of two opposite sides of the square metal frame.

3. The 2-bit programmable metasurface unit according to claim 2, characterized in that: The metal structure layer further includes: a first inductor, a second inductor, a third inductor and a first pad, a second pad, and a third pad located in the metal frame; The first inductor and the first pad are sequentially connected between the first square metal patch and the first positive electrode; The second inductor and the second pad are sequentially connected between the third rectangular metal patch and the second positive electrode; The second square metal patch is connected to the metal ground layer, specifically: the second square metal patch is connected to the metal ground layer through the third inductor and the third pad in sequence.

4. The 2-bit programmable metasurface unit according to claim 3, characterized in that: The first pad is connected to the first positive electrode through a second metallized through hole, the second metallized through hole runs through the metal structure layer to the bottom of the basic structure and is isolated from the metal ground layer; The second pad is connected to the second positive electrode through a third metallized through hole, the third metallized through hole runs through the metal structure layer to the bottom of the basic structure and is isolated from the metal ground layer; The third pad is connected to the metal layer through a fourth metallized through hole, and the fourth metallized through hole runs through the metal structure layer to the metal layer; The first metallized through hole penetrates from the metal frame to the bottom of the basic structure.

5. The 2-bit programmable metasurface unit according to claim 4, characterized in that: A circular isolation groove is arranged between the second metallized through hole and the third metallized through hole and the metal layer.

6. The 2-bit programmable metasurface unit according to claim 4, characterized in that: The side length of the square metal frame is any value between 16.4 mm and 16.6 mm; The length of the longitudinal side of the first square metal patch is any value between 2.33 mm and 2.35 mm, and the length of the transverse side thereof is any value between 1.8 mm and 1.9 mm; The length of the longitudinal side of the second square metal patch is any value between 8.2 mm and 8.4 mm, and the length of the transverse side thereof is any value between 9.1 mm and 9.2 mm; The length of the longitudinal side of the third rectangular metal patch is any value between 2.31 mm and 2.33 mm, and the length of the transverse side thereof is any value between 2.16 mm and 2.17 mm; The longitudinal edge refers to an edge along the arrangement direction of the first square metal patch, the second square metal patch, and the third square metal patch.

7. The 2-bit programmable metasurface unit according to claim 6, characterized in that: The first pad, the second pad and the third pad are square metal patches; The side length of the square metal patch is 1 mm.

8. The 2-bit programmable metasurface unit according to claim 6, characterized in that: The first pad is connected to the second metallized through hole through a first metal wire, and the length of the first metal wire is any value between 2.43 mm and 2.45 mm; The second pad is connected to the third metallized through hole through a second metal wire, and the length of the second metal wire is any value between 2.25 mm and 2.27 mm; The third pad is connected to the fourth metallized through hole through a third metal wire, and the length of the third metal wire is any value between 0.48 mm and 0.5 mm.

9. The 2-bit programmable metasurface unit according to any one of claims 1 to 8, characterized in that: The basic structure further includes: an adhesive layer and a second dielectric layer; the adhesive layer is located below the metal layer, the second dielectric layer is located below the adhesive layer, and a preset distance is separated between the adhesive layer and the second dielectric layer.

10. The 2-bit programmable metasurface unit according to claim 9, characterized in that: The dielectric constant of the first dielectric layer is any value between 2.6 and 3, the loss tangent thereof is any value between 0.001 and 0.0025, and the thickness thereof is any value between 2.8 mm and 3.1 mm; The dielectric constant of the adhesive layer is any value between 4.1 and 4.5, the loss tangent thereof is any value between 0.01 and 0.03, and the thickness thereof is any value between 0.05 mm and 0.15 mm; The dielectric constant of the second dielectric layer is any value between 4.1 and 4.5, the loss tangent thereof is any value between 0.01 and 0.03, and the thickness thereof is any value between 0.4 mm and 0.6 mm.

11. A 2-bit programmable metasurface, characterized in that: include: At least one 2-bit programmable metasurface unit as claimed in any one of claims 1 to 10.

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