A programmable metasurface unit chip and programmable metasurface

Abstract

The application discloses a programmable metasurface unit chip and a programmable metasurface. The unit chip comprises, from top to bottom, a first dielectric layer, a first bonding dielectric layer, a controllable metal layer, a second bonding dielectric layer, a third dielectric layer, a third metal layer, a third bonding dielectric layer, a fourth dielectric layer and a fourth metal layer. The controllable metal layer comprises a metal structure and a controllable element, is used for forming two isolated electromagnetic wave regulation channels, independently controls orthogonal polarized electromagnetic waves, and provides independently controllable electromagnetic responses for incident orthogonal polarized electromagnetic waves. The third metal layer is used as a radio frequency ground to improve electromagnetic wave reflection performance. The fourth metal layer is used for bias voltage input. Bias voltage is loaded onto the controllable element through metal holes of each layer. A plurality of unit chip arrays are arranged on a substrate to form a metasurface. The unit chip can greatly reduce the complexity of metasurface design and implementation, reduce production and maintenance costs, and promote the use of metasurfaces in wireless information systems.

Description

Technical Field

[0001] This invention belongs to the field of novel artificial electromagnetic materials technology, and specifically relates to a programmable metasurface unit chip and a programmable metasurface. Background Technology

[0002] Programmable metasurfaces are planar array structures composed of numerous artificially designed tunable electromagnetic units. They possess powerful capabilities for real-time electromagnetic wave manipulation and hold significant application potential in information fields such as wireless communication, radar remote sensing, and intelligent computing. The tunable electromagnetic units primarily consist of artificially designed metal structures and controllable components. By applying control signals to these components, the response characteristics of the electromagnetic units can be precisely controlled. Therefore, by setting the response states of each electromagnetic unit within the metasurface, specific electromagnetic response distributions can be achieved, enabling the metasurface to perform various important electromagnetic functions, such as beamforming, electromagnetic stealth, and waveform generation. With the rapid development of information technology, higher demands are being placed on the functionality and performance of programmable metasurfaces, leading to increasingly complex designs and control systems.

[0003] However, existing programmable metasurfaces often couple all electromagnetic units and control signal transmission structures together in their design. Therefore, once fabricated, the array size and shape are fixed, failing to meet practical needs such as adjusting array size and shape and replacing failed units, thus increasing the production and maintenance costs of metasurfaces. Moreover, current metasurface design cycles are long and experimental verification is complex, hindering the rapid development and iteration of complex metasurface-based systems and impeding the further development and engineering application of metasurfaces. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide a programmable metasurface unit chip that can achieve independent control of two orthogonally polarized electromagnetic waves.

[0005] Another object of the present invention is to provide a programmable metasurface based on the programmable metasurface unit chip, which helps to realize the rapid design, modification and reuse of information systems based on programmable metasurfaces.

[0006] Technical Solution: The programmable metasurface unit chip of the present invention includes at least one electromagnetic unit. The at least one electromagnetic unit includes at least three metal layers, at least three dielectric layers, and at least three bonding dielectric layers, arranged from top to bottom as follows: a first dielectric layer, a first bonding dielectric layer, a controllable metal layer, a second bonding dielectric layer, a third dielectric layer, a third metal layer, a third bonding dielectric layer, a fourth dielectric layer, and a fourth metal layer. The controllable metal layer includes a metal structure and a controllable element, used to form two isolated electromagnetic wave control channels to independently manipulate orthogonally polarized electromagnetic waves, providing an independently controllable electromagnetic response for the incident orthogonally polarized electromagnetic waves. The third metal layer serves as a radio frequency ground to improve the electromagnetic wave reflection performance of the unit chip. The fourth metal layer is used for bias voltage input. Metal holes are provided on the second bonding layer, the third dielectric layer, the third metal layer, the third bonding layer, and the fourth dielectric layer to apply the bias voltage input on the fourth metal layer to the controllable element.

[0007] Optionally, the metal structure of the controllable metal layer includes two orthogonally arranged first metal layers and second metal layers. A second dielectric layer is also disposed between the first metal layer and the second metal layer. The second dielectric layer separates the first metal layer and the second metal layer on its upper and lower surfaces. Controllable elements are disposed on the first metal layer and the second metal layer respectively. The first metal layer and the controllable elements thereon form a first control channel, and the second metal layer and the controllable elements thereon form a second control channel. The first control channel and the second control channel are isolated from each other.

[0008] Optionally, both the first metal layer and the second metal layer are butterfly-shaped metal patches, and the two wings of the butterfly-shaped metal patch are electrically connected through a controllable element.

[0009] Optionally, the unit chip further includes a metal wall structure, wherein the metal wall is disposed on the four sides of the at least one electromagnetic unit and connected to the third metal layer and the fourth metal layer; or disposed on the four sides of the structure between the first dielectric layer and the third dielectric layer and connected to the third metal layer; the metal wall is a single metal patch or a structure of spaced metal strips.

[0010] Optionally, the controllable element is a semiconductor device or a non-semiconductor device.

[0011] Optionally, the shapes of the layers of the at least one electromagnetic unit may be the same or different.

[0012] The programmable metasurface based on the unit chip includes a plurality of programmable metasurface unit chips and a metasurface substrate, wherein the plurality of programmable metasurface unit chips are arranged in an array on the metasurface substrate.

[0013] Optionally, the metasurface substrate includes a metal structure and a signal transmission structure. The plurality of programmable metasurface unit chips are detachably mounted on the metal structure. The signal transmission structure is used to provide control signals for each electromagnetic wave modulation channel of the plurality of metasurface unit chips, thereby setting their electromagnetic response state.

[0014] Optionally, the metal structure includes a top metal layer, a metal layer II, a metal layer III, and a bottom metal layer. The signal transmission structure includes a DC bias network disposed on the metal layer III and the bottom metal layer. The top metal layer is used to mount the plurality of programmable metasurface unit chips and to provide DC control voltage for the controllable elements of the plurality of programmable metasurface unit chips. The metal layer II serves as the ground plane for the DC signal, and the positive terminals of all controllable elements are connected to the metal layer II. The multi-channel control voltage is transmitted to the negative terminals of the controllable elements inside the plurality of programmable metasurface unit chips through the DC bias network and the metal holes disposed on each metal layer.

[0015] Optionally, the multi-channel control voltage is generated by a multi-channel programmable driver. The multi-channel programmable driver is connected to the metasurface substrate and includes a microcontroller, an analog multiplexer chip, a bus switching chip, and an input / output expansion chip. The microcontroller receives external control commands and parses the metasurface reflection phase distribution information therein, thereby converting it into internal commands that independently drive the electromagnetic wave control channels of each unit chip through the analog multiplexer chip, the bus switching chip, and the input / output expansion chip.

[0016] Beneficial effects: Compared with the prior art, the significant technical effects of the present invention are as follows: (1) By embedding the controllable element inside the metasurface unit chip, the controllable element is protected and the adverse effects of external water vapor, dust and static electricity are prevented. (2) By embedding the controllable element into different layers inside the unit chip, two independent electromagnetic wave response channels are realized in the same aperture. Because the response structure of the two electromagnetic wave control channels is designed in different layers and there is no physical connection, the control isolation of the two channels is improved, and independent control of two orthogonally polarized electromagnetic waves can be realized. (3) By setting the metal wall structure, the angular stability of its electromagnetic response can be effectively enhanced, and the mutual interference between the unit chips and the adjacent unit chips after the unit chips are arranged into an array can be effectively suppressed, which helps the metasurface to realize large-angle beam scanning. (4) The programmable metasurface unit chip can be easily connected and fixed on the substrate to form a programmable metasurface, realizing the decoupling design of the metasurface and the control system, which can greatly reduce the design complexity and implementation difficulty of the metasurface system, and reduce the production and cost of the metasurface. Maintenance cost; (5) Using programmable metasurface unit chips can overcome the problem that programmable metasurfaces cannot be expanded after processing. The metasurface unit chips can also be removed from the old substrate and installed on the new substrate to realize the reuse of metasurface unit chips. And the failure of the metasurface unit chips can be quickly repaired by replacing them; (6) Programmable metasurface unit chips with different functions can be integrated on the same substrate to form a composite programmable metasurface. New functions can also be realized by replacing different metasurface unit chips; (7) Programmable metasurfaces adopt a modular design, designing metasurface unit chips, metasurface substrates and multi-channel programmable drivers separately, and combining them into a whole through interfaces, which can improve the scalability and reusability of the metasurface system. And the two channels in all unit chips can be controlled independently. Attached Figure Description

[0017] Figure 1 This is a three-dimensional schematic diagram of a programmable metasurface unit chip provided according to an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the stacked structure of a programmable metasurface unit chip according to an embodiment of the present invention;

[0019] Figure 3 This is a detailed structural diagram of each layer of a programmable metasurface unit chip provided according to an embodiment of the present invention;

[0020] Figure 4The programmable metasurface unit chip provided in the present invention is used to simulate the reflection response as a function of frequency under the condition of perpendicular electromagnetic wave incidence. Among them, (a) is the simulation result of x-polarized reflection amplitude and phase under different equivalent capacitance states of varactor tube Dx, and (b) is the simulation result of y-polarized reflection amplitude and phase under different equivalent capacitance states of varactor tube Dy.

[0021] Figure 5 The graphs shown below illustrate the reflection response of a programmable metasurface unit chip as a function of incident angle, according to embodiments of the present invention. (a) shows the TM polarization reflection phase of the four equivalent capacitance states of the varactor diode Dx as a function of incident angle, (b) shows the TM polarization reflection amplitude of the four equivalent capacitance states of the varactor diode Dx as a function of incident angle, (c) shows the TE polarization reflection phase of the four equivalent capacitance states of the varactor diode Dy as a function of incident angle, and (d) shows the TE polarization reflection amplitude of the four equivalent capacitance states of the varactor diode Dy as a function of incident angle.

[0022] Figure 6 The graphs provided in this embodiment of the programmable metasurface unit chip under 60° incident wave irradiation show the reflection response of the varactor tubes in the orthogonal directions as a function of the reflection response. (a) is a graph showing the TM polarization reflection phase of the four equivalent capacitance states of the varactor tube Dx as a function of the equivalent capacitance state of the varactor tube Dy; (b) is a graph showing the TM polarization reflection amplitude of the four equivalent capacitance states of the varactor tube Dx as a function of the equivalent capacitance state of the varactor tube Dy; (c) is a graph showing the TE polarization reflection phase of the four equivalent capacitance states of the varactor tube Dy as a function of the equivalent capacitance state of the varactor tube Dx; and (d) is a graph showing the TE polarization reflection amplitude of the four equivalent capacitance states of the varactor tube Dy as a function of the equivalent capacitance state of the varactor tube Dx.

[0023] Figure 7 A physical image of a programmable metasurface unit chip provided according to an embodiment of the present invention;

[0024] Figure 8 This is a scene diagram illustrating the experimental measurement of the reflection characteristics of a programmable metasurface unit chip according to an embodiment of the present invention.

[0025] Figure 9 The graphs of the reflection response of the programmable metasurface unit chip provided in the embodiments of the present invention under the condition of perpendicular incidence of electromagnetic waves of different frequencies as a function of the reverse bias voltage of the varactor diode are shown. (a) is the measurement result of x-polarized reflection amplitude and phase of the varactor diode Dx under different reverse bias voltages, and (b) is the measurement result of y-polarized reflection amplitude and phase of the varactor diode Dy under different reverse bias voltages.

[0026] Figure 10The graph shows the variation of the reflection phase of the programmable metasurface unit chip provided in the embodiment of the present invention with the voltage state of the varactor diode in the orthogonal direction under 60° incident wave irradiation. (a) is the measurement result of the variation of the TM polarized reflection phase of the varactor diode Dx with the voltage state of the varactor diode Dy under the four voltage states, and (b) is the measurement result of the variation of the TE polarized reflection phase of the varactor diode Dy with the voltage state of the varactor diode Dx under the four voltage states.

[0027] Figure 11 A physical image of a programmable metasurface based on a metasurface unit chip according to an embodiment of the present invention;

[0028] Figure 12 This is a schematic diagram of the metasurface substrate principle of a programmable metasurface based on a metasurface unit chip according to an embodiment of the present invention, wherein (a) is the top metal layer, (b) is metal layer II, (c) is metal layer III, and (d) is the bottom metal layer;

[0029] Figure 13 This is a multi-channel programmable driver based on a metasurface unit chip and a programmable metasurface provided in an embodiment of the present invention.

[0030] Figure 14 This is a test scenario diagram of the far-field radiation pattern of a programmable metasurface based on a metasurface unit chip according to an embodiment of the present invention;

[0031] Figure 15 The test results of the beam scanning far-field radiation pattern of the programmable metasurface based on the metasurface unit chip provided in the embodiments of the present invention under normal incident and oblique incident electromagnetic wave irradiation are shown in the following figures: (a) is the TM polarized beam scanning far-field result of the metasurface under vertical incident wave irradiation, (b) is the TE polarized beam scanning far-field result of the metasurface under vertical incident wave irradiation, (c) is the TM polarized beam scanning far-field result of the metasurface under 30° incident wave irradiation, (d) is the TE polarized beam scanning far-field result of the metasurface under 30° incident wave irradiation, (e) is the TM polarized beam scanning far-field result of the metasurface under 60° incident wave irradiation, and (f) is the TE polarized beam scanning far-field result of the metasurface under 60° incident wave irradiation.

[0032] In the figure: 1-Detailed diagram of each layer of the programmable metasurface unit chip, 101-First dielectric layer, 102-Second dielectric layer, 103-Third dielectric layer, 104-Fourth dielectric layer, 105-First bonding dielectric layer, 106-Second bonding dielectric layer, 107-Third bonding dielectric layer, 108-First metal layer, 109-Second metal layer, 110-Third metal layer, 111-Fourth metal layer, 112-Metal wall, 113-Metal via. Detailed Implementation

[0033] Some embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0034] The radio frequency (RF) and baseband control components of a programmable metasurface employ different design methodologies. Decoupling these components can effectively reduce the design complexity of the programmable metasurface system. Therefore, a new type of programmable metasurface—one that is functionally stable, proven, and easy to integrate—can be developed, enhancing its adaptability and promoting its widespread application.

[0035] The following describes a programmable metasurface unit chip according to embodiments of the present invention with reference to the accompanying drawings. The present invention provides a programmable metasurface unit chip, each metasurface unit chip comprising an electromagnetic unit structure with a customizable electromagnetic response. It can be arrayed and combined on a substrate to form a programmable metasurface, providing a stable and independent electromagnetic response for orthogonally polarized incident electromagnetic waves over a wide angular range. This facilitates the rapid design, modification, and reuse of information systems based on programmable metasurfaces.

[0036] The programmable metasurface unit chip of the present invention includes at least one electromagnetic unit, wherein the at least one electromagnetic unit includes at least three metal layers, at least three dielectric layers, and at least three bonding dielectric layers, which are arranged from top to bottom as follows: a first dielectric layer, a first bonding dielectric layer, a controllable metal layer, a second bonding dielectric layer, a third dielectric layer, a third metal layer, a third bonding dielectric layer, a fourth dielectric layer, and a fourth metal layer. The controllable metal layer includes a metal structure and a controllable element, used to form two isolated electromagnetic wave control channels to independently manipulate orthogonally polarized electromagnetic waves, providing an independently controllable electromagnetic response for the incident orthogonally polarized electromagnetic waves. The third metal layer serves as a radio frequency ground to improve the reflection performance of the metasurface unit chip. The fourth metal layer is used for bias voltage input. Metal holes are provided on the second bonding layer, the third dielectric layer, the third metal layer, the third bonding layer, and the fourth dielectric layer to apply the bias voltage input on the fourth metal layer to the controllable element. This programmable metasurface unit chip has a controllable electromagnetic response, and can control electromagnetic wave reflection parameters, transmission parameters, radiation parameters, or any combination thereof, where electromagnetic wave parameters include amplitude, phase, polarization, frequency, etc.

[0037] The unit chip also includes a metal wall structure, which is disposed on the four sides of the at least one electromagnetic unit and connected to the third metal layer and the fourth metal layer; or disposed on the four sides of the structure between the first dielectric layer and the third dielectric layer and connected to the third metal layer; the metal wall is a whole metal patch or a metal strip structure arranged at intervals.

[0038] The programmable metasurface unit chip is a multi-layer structure based on printed circuit board technology. It can be manufactured using printed circuit board technology, and its outline can be of any shape. All dielectric layers, bonding dielectric layers, and metal layers can have the same or different geometric shapes, such as circles, triangles, rectangles, squares, hexagons, etc.

[0039] All metal layers are made of materials including tin, copper, silver, or gold, and combinations thereof.

[0040] The controllable element can be a semiconductor device such as a diode, varactor, transistor, analog switch, filter, amplifier, or a non-semiconductor device such as a liquid crystal, graphene, or vanadium dioxide.

[0041] The controllable metal layer's metal structure includes two orthogonally arranged first and second metal layers. A second dielectric layer is disposed between the first and second metal layers, separating the upper and lower surfaces of the first and second metal layers. Controllable elements are respectively disposed on the first and second metal layers. The first metal layer and its controllable elements form a first control channel, and the second metal layer and its controllable elements form a second control channel. The first and second control channels are isolated from each other. More preferably, both the first and second metal layers are butterfly-shaped metal patches, and the two flaps of the butterfly-shaped metal patch are electrically connected through controllable elements. Specifically, as shown... Figure 1-3As shown, the programmable metasurface unit chip has a multilayer printed circuit board structure, consisting of a dielectric layer, an adhesive dielectric layer, a metal structure, and controllable components. It includes four metal layers, four dielectric layers, and three adhesive dielectric layers, namely: first dielectric layer 101, second dielectric layer 102, third dielectric layer 103, fourth dielectric layer 104, first adhesive dielectric layer 105, second adhesive dielectric layer 106, third adhesive dielectric layer 107, first metal layer 108, second metal layer 109, third metal layer 110, and fourth metal layer. 111; The dielectric layer and bonding dielectric layer of the programmable metasurface unit chip are square. The size of the dielectric layer on the upper part of the unit chip is slightly smaller than that on the lower part, leaving space for physical processing; The first metal layer 108 and the second metal layer 109 are respectively disposed on the upper and lower surfaces of the second dielectric layer 102. In this embodiment, both the first metal layer 108 and the second metal layer 109 are butterfly-shaped metal patches, and the first metal layer 108 and the second metal layer 109 are orthogonally arranged. Varactor tubes are selected as controllable elements, and the two varactor tubes are installed. Inside the metasurface unit chip, varactor Dx is mounted at the center of butterfly-shaped metal patch 109 in the x-direction, and varactor Dy is mounted at the center of butterfly-shaped metal patch 108 in the y-direction. The third metal layer 110 is a square metal patch, which serves as an RF ground to improve the electromagnetic wave reflection performance of the metasurface unit chip. The fourth metal layer 111 includes a pad structure, in which the four middle pads are used for DC bias voltage input, and the outer pads are used to fix the metasurface unit chip on the substrate. Metal wall structures 112 are designed on the four sides of all dielectric layers and bonding dielectric layers of the metasurface unit chip, which are connected to the third metal layer to form a reflective cavity, which can effectively enhance the angular stability of its electromagnetic response and connect to the outer pads in the fourth metal layer 111. Four metal holes 113 are provided on the second dielectric layer, the second bonding dielectric layer, the third dielectric layer, the third metal layer, the third bonding layer, and the fourth dielectric layer, which are used to connect the middle pad of the fourth metal layer 111 and the two butterfly-shaped metal patches in the controllable metal layer, and are used to apply the input bias voltage to the varactor.

[0042] In one embodiment of the present invention, the side length of the programmable metasurface unit chip is set to p = 15.8 mm, while the side length of its upper half (including the first dielectric layer 101, the first bonding dielectric layer 105, the second dielectric layer 102, the second bonding dielectric layer 106, and the third dielectric layer 103) is designed to be e = 15.4 mm; the materials of the first dielectric layer 101, the second dielectric layer 102, the third dielectric layer 103, and the fourth dielectric layer 104 are Rogers 4350 type substrates with thicknesses of 0.1 mm, 0.1 mm, 1.5 mm, and 0.5 mm, respectively, and their relative permittivity is 3.66 and loss tangent is 0.0037; the first bonding dielectric layer 105, the second bonding dielectric layer 106, and the third bonding dielectric layer 107 use Rogers 4450F type substrates to bond the dielectric layer and the metal layer into a whole, and their permittivity is 3.52 and loss tangent is 0.004; because the MACOM varactor is used... The MAVR-000120-14110P has a thickness of 0.2mm, so the thickness of the adhesive dielectric layer is selected to be 0.3mm, leaving sufficient thickness space for embedding the varactor tube; in order to obtain similar x and y polarization reflection responses, the butterfly-shaped metal patches 108 and 109 have the same geometric dimensions, with geometric parameters of b=14mm, c=6.1mm, d=1.3mm, g=2.2mm and w=0.5mm, respectively; in addition, all metal structures use copper as the conductive material, with a thickness of 35μm.

[0043] By controlling the voltages across the varactor diodes Dx and Dy respectively, the capacitance value of the varactor diode can be adjusted, thereby controlling the x and y polarization electromagnetic responses of the programmable metasurface unit chip. In the full-wave simulation, the varactor diode is modeled as a series circuit of a resistor-inductor-capacitor with adjustable capacitance, where the resistance is set to Rs = 1.1Ω, the inductance is set to Ls = 0.4nH, and the adjustable equivalent capacitance C... T The range is from 0.15 pF to 0.75 pF; Figure 4 (a) shows the simulation results of the reflection amplitude and phase of the metasurface unit chip under the condition of perpendicular incidence of x-polarized electromagnetic wave, with different equivalent capacitance values ​​of the varactor tube Dx. Figure 4 Figure (b) shows the simulation results of the reflection amplitude and phase of the metasurface unit chip under the condition of perpendicular incidence of y-polarized electromagnetic waves, with different equivalent capacitance values ​​of the varactor diode Dy. Comparing the two simulation results, it can be found that the metasurface unit chip has similar reflection responses to orthogonally polarized incident waves. For x-polarization, when the equivalent capacitance value C of the varactor diode Dx is... TxWhen reduced to 0.15pF, the amplitude resonant point shifts to 5.5GHz at higher frequencies, and within the frequency range of 4.5GHz to 5.2GHz, the adjustable reflection phase range exceeds 270°, meeting the minimum phase shift range requirement for 2-bit phase encoding, while the maximum phase shift range is 334°. For y-polarization, the amplitude resonant point of this metasurface unit chip changes with the equivalent capacitance C of the varactor diode Dy. Ty Exhibiting similar changes, its adjustable reflection phase shift range also exceeds 270° in the frequency range of 4.5GHz to 5.2GHz, with a maximum value of 332°; therefore, four reflection phase coding states with a spacing of 90° can be determined for this metasurface unit chip to form a 2-bit phase code, thereby digitally controlling x and y polarized electromagnetic waves respectively.

[0044] In this embodiment of the invention, the metal walls 112 around the programmable metasurface unit chip can effectively suppress mutual interference between it and adjacent electromagnetic units after it is arrayed, and can form a reflective cavity with the radio frequency ground in the third metal layer 110 to enhance the angular stability of its electromagnetic response; here, electromagnetic waves obliquely incident from the xoz plane are selected to evaluate the angular stability of the metasurface unit chip, and the geometric symmetry of the structure ensures that electromagnetic waves obliquely incident from the yoz plane have similar characteristics. Figure 5 Figures (a) to (d) show the reflection phase and amplitude responses of the four encoded states of the metasurface unit chip under TM (x-polarized in the xoz plane) and TE (y-polarized in the xoz plane) polarizations, respectively, when electromagnetic waves are incident at different zenith angles θ; Figure 5 From (a) and (c), it can be seen that for electromagnetic waves incident from the xoz plane at zenith angles ranging from 0° to 60°, the reflection phase errors of TM and TE polarizations are approximately 20° and 30°, respectively, significantly smaller than the 90° phase interval of 2-bit phase encoding. This indicates that the reflection phase of the metasurface unit chip can remain stable under different incident angles; from Figure 5 As can be seen from (b) and (d), the reflection amplitude of the metasurface unit chip remains stable under different incident angles; therefore, the metasurface unit chip can maintain the stability of the preset reflection response, especially under large-angle incident conditions.

[0045] By designing electromagnetic structures with different polarizations in different metal layers, the physical connection between the two electromagnetic structures is avoided, which can effectively improve the isolation of the programmable metasurface unit chip for manipulating orthogonally polarized electromagnetic waves. Figure 6 Figures (a) to (d) show the curves illustrating the reflection amplitude and phase response of the metasurface unit chip under obliquely incident electromagnetic wave irradiation as a function of the orthogonal direction varactor tube state; from Figure 6From the changes in the TM polarization phase response of the varactor diode Dx under the four states in (a) with the equivalent capacitance of the varactor diode Dy, it can be seen that the TM polarization phase response of this metasurface unit chip is mainly controlled by the varactor diode Dx. Therefore, when the equivalent capacitance of the varactor diode Dy changes, its reflection phase remains stable, and the phase change does not exceed 7°; similarly, from Figure 6 The results in (c) show that the TE polarization reflection phase of the varactor diode Dy in all four states remains stable even when the equivalent capacitance of the varactor diode Dx changes, and the phase change is less than 7°; according to Figure 6 As shown in (b) and (d), the reflection amplitude remains stable even when the orthogonal direction of the varactor tube is changed. As an example, the frequency of the TM and TE polarized obliquely incident electromagnetic waves used in the above simulation is 4.9 GHz, the incident plane is the xoz plane, and the incident zenith angle is θ. i =60°; under other frequencies and incident angles, the metasurface unit chip also has similar and almost independent orthogonal polarization control performance.

[0046] In this embodiment of the invention, the programmable metasurface unit chip can be manufactured using advanced printed circuit board technology, which includes the process of embedding electronic components into the circuit board, and the resulting physical product is as follows: Figure 7 As shown, a directional marker is added to the upper left corner of the metasurface unit chip to clearly indicate its orientation, facilitating integration onto the substrate. The chip contains two varactors, denoted as Dx and Dy, which are soldered to the middle of butterfly-shaped metal patches in the x and y directions, respectively. The outlines of the two butterfly-shaped metal patches are also printed on the upper surface of the metasurface unit chip, adding more visual appeal. Additionally, the portion of the metal vias above the butterfly-shaped metal patches, which might affect RF performance, was removed, and the remaining holes were filled with epoxy resin, forming four brown dots in the center. The bottom surface of the metasurface unit chip features pin pads, divided into a center pad and peripheral pads. The center pad is primarily used for inputting the control voltage of the two varactors, while the peripheral pads not only fix the chip but also serve as RF ground interfaces connected to the RF ground structure within the chip. In addition to the center and peripheral pads, a layer of green solder resist ink is applied to prevent potential short circuits during soldering.

[0047] The electromagnetic response characteristics of this programmable metasurface unit chip were measured experimentally. The experimental scenario was as follows: Figure 8 As shown, after assembling multiple metasurface unit chips into a small array, their reflection response can be measured using the free-space method. First, the relationship between the x and y polarization reflection responses of the metasurface unit chip and the bias voltages on the varactor diodes Dx and Dy under perpendicular electromagnetic wave incidence was experimentally measured. The results are as follows: Figure 9As shown in (a) and (b), the measurement results show that the controllable phase shift range of both polarizations exceeds 270° in the range of 4.7 GHz to 5.0 GHz. The maximum phase shift ranges of x and y polarizations are 330° and 328° respectively at 4.7 GHz, while the results at 5.0 GHz are 297° and 287° respectively. Therefore, the phase encoding state of the metasurface unit chip can be determined based on the above measurement results. In addition, the measured reflection amplitude loss is basically less than 5.0 dB, and better reflection amplitude performance can be obtained at higher frequency bands. There is a slight difference between the measured reflection amplitude and the simulated value. The error is mainly concentrated at the resonance position because the measurement results at the resonance position are easily affected by non-ideal factors of the metasurface unit chip sample. Therefore, the measured reflection coefficient of the metasurface unit chip is basically consistent with the simulation results, proving its effectiveness in controlling the orthogonal polarization reflection phase.

[0048] To verify the performance of this programmable metasurface unit chip in decoupling and controlling orthogonally polarized obliquely incident electromagnetic waves, its performance at 4.9 GHz was measured when electromagnetic waves were emitted from the xoz plane at a zenith angle θ. i The reflection phase at an incident angle of 60° is as follows: Figure 10 As shown in (a) and (b); from Figure 10 From (a), we can obtain that the TM polarization reflection phase of the varactor diode Dx in the four states remains stable when the voltage across the varactor diode Dy is changed; from Figure 10 As can also be seen in (b), the TE polarization reflection phase of the varactor Dy in the four states can remain stable when the voltage across the varactor Dx is changed; the variation range of the two polarization reflection phase measurements is less than 8°, which is consistent with the simulation results; moreover, similar results can be obtained at other incident angles; therefore, this metasurface unit chip can manipulate orthogonally polarized electromagnetic waves approximately independently, especially in the case of large-angle incident.

[0049] The programmable metasurface unit chip proposed in this embodiment integrates two highly isolated electromagnetic wave control channels within the same electromagnetic unit to manipulate orthogonally polarized electromagnetic waves, providing a stable and independent electromagnetic response for orthogonally polarized electromagnetic waves incident over a wide angle range. By arranging this metasurface unit chip in an array on a substrate, metasurfaces of different sizes and shapes can be formed, which can be used for large-scale real-time control of spatial electromagnetic waves, promoting the application of metasurface-based information systems in wireless communication, the Internet of Things, and intelligent sensing.

[0050] Based on the aforementioned programmable metasurface unit chip, this invention also designs a programmable metasurface, comprising a plurality of programmable metasurface unit chips and a metasurface substrate, wherein the plurality of programmable metasurface unit chips are arranged in an array on the metasurface substrate. The metasurface substrate can be of any size and shape.

[0051] The metasurface substrate has a structure for connecting the metasurface unit chip, which can install and remove the metasurface unit chip. The connection structure can be a fixing hole, pad, clip, socket, magnet, adhesive, etc.

[0052] In this embodiment, the connection structure between the metasurface unit chip and the metasurface substrate is a pad, and the metasurface unit chip can be soldered onto the metasurface substrate.

[0053] The metasurface substrate is a multilayer structure based on printed circuit board (PCB) technology and can be manufactured using PCB processes. The programmable metasurface can independently provide control signals for each electromagnetic wave modulation channel within each metasurface unit chip.

[0054] The metasurface substrate includes a metal structure and a signal transmission structure. The plurality of programmable metasurface unit chips are detachably mounted on the metal structure. The signal transmission structure provides control signals to each electromagnetic wave modulation channel of the plurality of metasurface unit chips, thereby setting their electromagnetic response state. The metal structure includes a top metal layer, metal layer II, metal layer III, and a bottom metal layer. The signal transmission structure includes a DC bias network disposed on metal layer III and the bottom metal layer. The top metal layer is used to mount the plurality of programmable metasurface unit chips and provides DC control voltage to the controllable elements of the plurality of programmable metasurface unit chips. Metal layer II serves as the ground plane for the DC signal, and the positive terminals of all controllable elements are connected to metal layer II. The multi-channel control voltage is transmitted to the negative terminals of the controllable elements inside the plurality of programmable metasurface unit chips through the DC bias network and metal vias disposed on each metal layer.

[0055] The multi-channel control voltage is generated by a multi-channel programmable driver, which is connected to the metasurface substrate via a flexible flat cable connector. The multi-channel programmable driver includes a microcontroller, an analog multiplexer chip, a bus switching chip, and an input / output expansion chip. The microcontroller receives external control commands and parses the metasurface reflection phase distribution information therein, thereby converting it into internal commands that independently drive the electromagnetic wave control channels of each unit chip through the analog multiplexer chip, the bus switching chip, and the input / output expansion chip.

[0056] The following description, with reference to the accompanying drawings, describes a programmable metasurface based on a metasurface unit chip according to an embodiment of the present invention. This programmable metasurface, constructed by mounting the metasurface unit chip onto a metasurface substrate, achieves decoupling of the radio frequency and baseband portions of the programmable metasurface, reduces the design complexity of the programmable metasurface system, and promotes the widespread application of programmable metasurfaces.

[0057] like Figure 11 As shown, this programmable metasurface based on metasurface unit chips consists of 441 metasurface unit chips soldered onto a metasurface substrate, with an overall size of 366mm × 366mm. Space is left on all four sides for mounting brackets. Of all the mounted unit chips, nearly half are used for the first time, while the remaining unit chips are reused, demonstrating the reusability of the unit chips. It can be observed that the surface color of the reused unit chips differs from that of the first-time used ones. This is mainly due to the high temperatures during unit chip removal. A high-temperature resistant material, such as solder resist ink, can be applied to the surface to prevent color changes.

[0058] The unit chip integrates two orthogonally polarized electromagnetic wave control channels in the same aperture plane, and the modulation interference between the two channels is very small. At the same time, the unit chip has large-angle stability and can provide a stable electromagnetic response to electromagnetic waves incident over a wide angle range. Therefore, by integrating this unit chip, the programmable metasurface has two orthogonally polarized electromagnetic wave control channels and has large-angle stability and polarization decoupling characteristics.

[0059] In this embodiment of the invention, the metasurface substrate is mainly used to support the metasurface unit chips and provide them with control signals. For demonstration purposes, the metasurface substrate designed here can accommodate 21×21 unit chips, such as... Figure 12 As shown in (a) to (d), the metasurface substrate comprises four metal layers. The top metal layer contains soldering interfaces for mounting all unit chips, where pads XP, XN, YP, and YN are connected to the positive and negative terminals of varactor diodes Dx and Dy, respectively, providing DC control voltages for the two varactor diodes. All pads on the metasurface substrate used for RF ground connections of the unit chips are connected together, thus connecting the RF grounds inside all mounted unit chips to form a complete RF ground plane, which enhances the reflectivity of the metasurface. Metal layer II is a complete metal patch serving as a ground plane for DC signals, and the positive terminals of all varactor diodes are connected to this layer. Metal layer III and the bottom metal layer contain DC bias networks that transmit the multi-channel control voltage input from the rear connector to the negative terminals of the varactor diodes inside all unit chips. The rear connector is divided into two groups and connected to the voltage output terminals of the multi-channel programmable driver via flexible flat cables, receiving control signals from varactor diodes Dx and Dy, respectively. This metasurface substrate can be manufactured using conventional printed circuit board processes and materials, with minimal impact on the electromagnetic properties of the metasurface.

[0060] To control the varactor transistors Dx and Dy within each unit chip, a multi-channel programmable driver was designed to provide control voltages for them, such as... Figure 13As shown, a microcontroller is used as the main control module of the driver to receive external control commands and parse the metasurface reflection phase distribution information to generate internal commands to drive all digital chips. Four voltages are used to set the metasurface reflection phase encoding state. To simplify the driver design, an analog multiplexer chip is used to output the target voltage. Each multiplexer chip can select one of the four preset voltages as its output by controlling its logic input pins. To independently set the control voltages of the varactors Dx and Dy, the multiplexer chips are divided into two groups, allowing the preset voltages of different groups to be set independently. To control all the multiplexer chips, input / output (I / O) expansion chips and bus switching chips are used through inter-integrated... The circuit (I2C) bus protocol expands the I / O pins of the microcontroller; in order to match the scalable array size of the metasurface, the driver also uses a modular design, with the bus switching module and I / O expansion module designed on different printed circuit boards; finally, three high-precision regulated power supplies are used to power all the chips and provide eight control voltages for the varactor diodes Dx and Dy.

[0061] Real-time beam scanning is a crucial function of programmable metasurfaces. Benefiting from the electromagnetic wave manipulation capabilities of polarization decoupling and enhanced reflection response angle stability, this metasurface can simultaneously and independently achieve large-angle beam scanning of orthogonally polarized obliquely incident waves. The reflection phase distribution on the programmable metasurface can be calculated using the generalized Snell's law, and then the calculated continuous phase results are quantized into four selected coded states; such as... Figure 14 As shown, the experimental measurement of the metasurface far-field radiation pattern was conducted in a microwave anechoic chamber to reduce the influence of environmental electromagnetic scattering. A vector network analyzer was used to measure the reflection coefficient of the metasurface at different zenith angles θ in the xoz plane. The dual-channel programmable metasurface and the transmitting antenna were placed at both ends of the turntable support with a spacing of 2m to meet the far-field conditions for plane wave generation. The receiving antenna was located in the far-field region.

[0062] The far-field pattern test results of the programmable metasurface™ and TE-polarized large-angle beam scanning are as follows: Figure 15 As shown in (a) to (f), electromagnetic waves are incident from the xoz plane at different zenith angles, and the operating frequency is 4.9 GHz; Figure 15 Images (a) and (b) show the incident zenith angle θ, respectively. i =0° results, where the reflected beams of the programmable metasurface point to ±10°, ±30° and ±60° respectively; Figure 15 Images (c) and (d) show the incident zenith angle θ, respectively. i=30° results, where the reflected beams of the programmable metasurface point to 0°, ±20° and ±60° respectively; Figure 15 Figures (e) and (f) show the incident zenith angle θ, respectively. i The results were obtained at 60°, with the reflected beams pointing at 0°, ±30°, and ±50° respectively. Overall, all reflection pattern measurements were consistent with the theoretical calculations, verifying that the metasurface can achieve scanning of dual-polarized reflected beams over a wide angle range. A slight degradation in the metasurface reflection beam pattern measurements was observed, mainly due to unavoidable non-ideal factors, including quantization errors caused by finite coding states, changes in reflection phase with angle, and finite array size. Using optimization algorithms and larger array sizes can help reduce distortion and enhance the metasurface's performance.

[0063] The programmable metasurface based on metasurface unit chips proposed in this invention enables rapid construction of programmable metasurfaces using proven programmable metasurface unit chips. This modular design effectively reduces the complexity of programmable metasurface system design and allows for the rapid realization of programmable metasurfaces of different sizes and shapes, improving the scalability and reusability of metasurfaces. Therefore, this programmable metasurface based on metasurface unit chips can be used for large-scale distributed real-time control of spatial electromagnetic waves, and has significant application prospects in electromagnetic information fields such as wireless communication, the Internet of Things, and intelligent sensing.

[0064] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0065] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

Claims

1. A programmable metasurface unit chip, characterized by, The at least one electromagnetic unit comprises at least three metal layers, at least three dielectric layers and at least three adhesive dielectric layers, from top to bottom in turn: a first dielectric layer, a first adhesive dielectric layer, a controllable metal layer, a second adhesive dielectric layer, a third dielectric layer, a third metal layer, a third adhesive dielectric layer, a fourth dielectric layer and a fourth metal layer, wherein the controllable metal layer comprises a metal structure and a controllable element, for forming two isolated electromagnetic wave regulation channels to independently control orthogonal polarized electromagnetic waves, and providing an independently controllable electromagnetic response for incident orthogonal polarized electromagnetic waves; the metal structure of the controllable metal layer comprises two orthogonally arranged first and second metal layers, and a second dielectric layer is further arranged between the first and second metal layers, the second dielectric layer isolates the first and second metal layers on its upper and lower surfaces, and the first and second metal layers are respectively provided with controllable elements, the first metal layer and the controllable element arranged thereon form a first regulation channel, the second metal layer and the controllable element arranged thereon form a second regulation channel, and the first and second regulation channels are isolated from each other; the third metal layer serves as a radio frequency ground for improving the electromagnetic wave reflection performance of the unit chip; the fourth metal layer is used for bias voltage input; the second adhesive layer, the third dielectric layer, the third metal layer, the third adhesive layer and the fourth dielectric layer are all provided with metal holes for loading the bias voltage input on the fourth metal layer to the controllable elements.

2. The programmable metasurface unit chip of claim 1, wherein, The first and second metal layers are both butterfly-shaped metal patches, and the two wings of the butterfly-shaped metal patch are electrically connected through the controllable element.

3. The programmable metasurface unit chip of claim 1, wherein, The unit chip further comprises a metal wall structure, the metal wall is arranged on four sides of the at least one electromagnetic unit and connected with the third and fourth metal layers, or arranged on four sides of a structure between the first and third dielectric layers and connected with the third metal layer; the metal wall is an entire metal patch or a metal strip structure arranged at intervals.

4. The programmable metasurface unit chip of claim 1, wherein, The controllable element is a semiconductor device or a non-semiconductor device.

5. The programmable metasurface unit chip of claim 1, wherein, The shapes of the layers of the at least one electromagnetic unit are the same or different.

6. A programmable metasurface, characterized in that, A plurality of programmable metasurface unit chips according to any one of claims 1-5 are arranged in an array on a metasurface substrate.

7. The programmable metasurface of claim 6, wherein, The metasurface substrate comprises a metal structure and a signal transmission structure, the plurality of programmable metasurface unit chips are detachably mounted on the metal structure, and the signal transmission structure is used to provide a control signal for each electromagnetic wave regulation channel of the plurality of metasurface unit chips, thereby setting the electromagnetic response state thereof.

8. The programmable metasurface of claim 7, wherein, The metal structure comprises a top metal layer, a metal layer , a metal layer and a bottom metal layer, and the signal transmission structure comprises a direct current bias network arranged on the metal layer and the bottom metal layer, the top metal layer is used for mounting the plurality of programmable metasurface unit chips and providing direct current control voltages for controllable elements of the plurality of programmable metasurface unit chips; the metal layer serves as a ground plane of direct current signals, and positive poles of all the controllable elements are connected to the metal layer ; and multi-channel control voltages are transmitted to negative poles of the controllable elements inside the plurality of programmable metasurface unit chips through the direct current bias network and metal holes arranged on the metal layers.

9. The programmable metasurface of claim 8, wherein, The multi-channel control voltage is generated by a multi-channel programmable driver connected with the metasurface substrate, which comprises a single-chip microcomputer, an analog multiplexing chip, a bus switching chip and an input / output expansion chip. The single-chip microcomputer is used for receiving external control instructions and analyzing metasurface reflection phase distribution information therein, so as to convert into internal instructions to independently drive each electromagnetic wave regulation channel of each unit chip through the analog multiplexing chip, the bus switching chip and the input / output expansion chip.

Images