A reconfigurable metasurface structure with coplanar design of structure and bias line

Abstract

This invention discloses a reconfigurable metasurface structure with a coplanar design of structure and bias line, relating to the field of artificial electromagnetic material design technology. The invention connects multiple metal patches to form an irregularly shaped metal structure. Two irregularly shaped metal structures are symmetrically arranged on a dielectric substrate layer, and a varactor diode is embedded between the two irregularly shaped metal structures. The irregularly shaped metal structures can be discretized into bias lines to achieve coplanarity between the structure and the bias lines. When electromagnetic waves are incident on the metasurface structure, the resonance characteristics of the two irregularly shaped metal structures change by altering the capacitance of the varactor diode, achieving the purpose of dynamically manipulating the electromagnetic response of the electromagnetic waves. This invention's integrated design of structure and bias line has broad application prospects in fields such as adaptive intelligent sensing.

Description

Technical Field

[0001] This invention relates to the field of artificial electromagnetic material design technology, and in particular to a reconfigurable metasurface structure with a coplanar design of structure and bias line. Background Technology

[0002] Metasurfaces are two-dimensional, ultrathin planar metamaterials composed of numerous artificial microstructures arranged periodically or aperiodically. They can manipulate electromagnetic waves with greater degrees of freedom, achieving miniaturization of microwave or optical devices. Through careful design of the unit structure, metasurfaces can modulate parameters such as amplitude, phase, polarization, and propagation mode with subwavelength resolution and perform wavefront shaping within the wavelength range. They can realize absorption, superlensing, cloaking, and holographic imaging, replacing traditional microwave and optical devices. In recent years, the proposal of some multifunctional metasurfaces has met the requirements of high integration in practical components and has attracted widespread attention from researchers. The proposal of dynamic metasurfaces further expands functionality in the time dimension. Currently, some control methods are applied to dynamic metasurfaces, including temperature control, optical control, and electrical control. Electrical control is the most commonly used method to realize dynamic metasurfaces, mainly using voltage bias to quickly and conveniently change the electromagnetic response of the metasurface unit. PIN diodes or varactors are commonly used electronic components in the design of reconfigurable metasurfaces.

[0003] In this specific study, PIN diodes were introduced into the coded metasurface to modulate the RCS of the reflector. The on / off states of the diodes correspond exactly to the 0 and 1 states, which can be used to design a 1-bit coded metasurface. Based on 1-bit phase modulation, different coding sequences can be constructed to achieve functions such as scattering, holography, and beam deflection. Further optimization of the number and position of the diodes can design more coding modes, such as 2-bit or even multi-bit coding, thereby achieving richer electromagnetic functions. However, the on / off states of the PIN diodes lack continuity, which limits the functional design. Therefore, varactor diodes are integrated into the metasurface to expand the electromagnetic functions.

[0004] However, as the functions become more and more complex, the external circuits and components of metasurfaces, such as metallized holes and bias lines, also become more and more complicated. This greatly hinders the large-scale design of metasurfaces, significantly reduces their control performance, and makes it difficult to achieve the electromagnetic response of dynamically manipulating electromagnetic waves. Summary of the Invention

[0005] This invention provides a reconfigurable metasurface structure with a coplanar design of structure and bias lines. This can solve the problem in the prior art where, as the functions become more complex, the external circuits and components of the metasurface, such as metallized holes and bias lines, also become increasingly complex. This greatly hinders the large-scale design of metasurfaces and significantly reduces their control performance.

[0006] This invention provides a reconfigurable metasurface structure with a coplanar design of structure and bias line, including a metal patch layer, an active device, a dielectric substrate layer, and a reflective backplane layer;

[0007] The metal patch layer includes two symmetrically arranged, irregularly shaped metal structures, which are plated on the top surface of the dielectric substrate layer; an active device, which is a varactor diode, is embedded between the two irregularly shaped metal structures; the reflective backplate layer is disposed on the bottom surface of the dielectric substrate layer.

[0008] The irregularly shaped metal structure is composed of multiple interconnected metal patches, and the metal structure is discrete into bias lines. By changing the bias voltage applied across the varactor diode, the capacitance of the varactor diode is changed, thereby altering the resonant characteristics of the irregularly shaped metal structure discrete into bias lines.

[0009] Preferably, the irregularly shaped metal structure is made of copper and is plated on the top surface of the dielectric substrate layer using a printed circuit board.

[0010] Preferably, the active device is an SMV1405-079LF varactor diode;

[0011] The varactor diode and the two irregularly shaped metal structures are equivalent to a series circuit containing a resistor, an inductor, and a capacitor, with a resistance of 0.8Ω and an inductance of 0.7nH.

[0012] When the bias voltage applied to the varactor diode changes from 30V to 0V, the capacitance changes from 0.63pF to 2.67pF.

[0013] Preferably, the dielectric substrate layer is made of polytetrafluoroethylene (PTFE) plate F4B, with a dielectric constant of ε. r =2.65, the loss tangent is tanδ=0.001, used to adjust the impedance of the metasurface structure and change the amplitude and phase of the incident electromagnetic wave.

[0014] Preferably, the reflective backplate layer is made of copper plate and is used to reflect incident electromagnetic waves.

[0015] Preferably, when the frequency of the electromagnetic wave incident on the metasurface is 4.5 GHz, the metasurface structure achieves a 180° phase difference in reflection phase and a 1 dB amplitude difference in reflection amplitude.

[0016] This invention provides a reconfigurable metasurface structure with a coplanar design of structure and bias line, which has the following advantages compared with the prior art:

[0017] This invention connects multiple metal patches to form an irregularly shaped metal structure, symmetrically arranges two irregularly shaped metal structures on a dielectric substrate layer, and embeds a varactor diode between the two irregularly shaped metal structures. The irregularly shaped metal structure can be discretized into bias lines, thereby achieving a coplanar design of the structure and bias lines. This simplifies the metasurface and significantly improves control performance. It has broad application prospects in fields such as adaptive intelligent sensing.

[0018] Secondly, when electromagnetic waves are incident on the metasurface structure, the resonant characteristics of the two irregularly shaped metal structures can be changed by altering the capacitance of the varactor diode, thereby achieving the purpose of dynamically manipulating the electromagnetic response of the electromagnetic waves. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of a reconfigurable metasurface structure with a coplanar design of structure and bias line, provided by an embodiment of the present invention.

[0020] Figure 2 A schematic diagram of a top-down connectivity matrix generation algorithm for a reconfigurable metasurface structure with coplanar design of structure and bias line provided in an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram illustrating the principle of a reconfigurable metasurface structure with a coplanar design of structure and bias line, provided by an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of a design method for a reconfigurable metasurface structure with coplanar structure and offset line, provided by an embodiment of the present invention; wherein (a) is a schematic diagram of the structure and geometric parameters; wherein (b) is a 1 / 4 unit structure and the corresponding two-dimensional matrix;

[0023] Figure 5 This is a schematic diagram of the electromagnetic response of a varactor diode with a reconfigurable metasurface structure designed with coplanar structure and bias line in different states, provided for an embodiment of the present invention; wherein (a) is a schematic diagram of the simulated reflection phase; and wherein (b) is a schematic diagram of the simulated reflection amplitude.

[0024] Figure 6 This is a schematic diagram of the test results of a reconfigurable metasurface structure with a coplanar design of structure and bias line provided in an embodiment of the present invention; (a) and (b) are schematic diagrams of the encoding sequence; and (c) and (d) are far-field radiation patterns.

[0025] The components are: 1. Metal patch layer, 2. Active device, 3. Dielectric substrate layer, and 4. Reflective backplane layer. Detailed Implementation

[0026] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0027] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0028] 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 technical features indicated. 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, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0029] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0031] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0032] See Figure 1 The present invention provides a reconfigurable metasurface structure with a coplanar design of structure and bias line, comprising a metal patch layer 1, an active device 2, a dielectric substrate layer 3, and a reflective backplane layer 4 in sequence.

[0033] The metal patch layer 1 consists of two symmetrical metal structures that are discretized into irregular shapes. It can be represented by a 0-1 two-dimensional matrix and is plated on the dielectric substrate layer 3 using printed circuit board technology. The metal patch layer 1 integrates the unit structure and bias line on a single plane and is implemented using copper with a thickness of 0.017 mm.

[0034] Active device 2 is an SMV1405-079LF varactor diode; active device 2 is soldered between two irregularly shaped metal patches on metal patch layer 1 to change the resonant characteristics of metal patch layer 1 and manipulate electromagnetic waves; active device 2 is equivalent to a series circuit of resistor, inductor and capacitor, where the resistor is 0.8Ω and the inductor is 0.7nH; the capacitance value changes with the applied voltage, and when the bias voltage changes from 30V to 0V, the capacitance can change from 0.63pF to 2.67pF.

[0035] The dielectric substrate layer 3 has a dielectric constant ε r =2.65, and the loss tangent is tanδ=0.001. Polytetrafluoroethylene (F4B) is used to adjust the impedance of the metasurface unit and change the electromagnetic wave amplitude, phase and other parameters; one side of the dielectric substrate layer 3 is the metal patch layer 1, and the other side is the reflective backplate layer 4.

[0036] The reflective backplate layer 4 is made of copper and has a thickness of 0.017 mm. It is used to reflect electromagnetic waves and its size is the same as that of the dielectric substrate layer 3.

[0037] When electromagnetic waves are incident on the metasurface structure, the capacitance of the varactor diode is changed by altering the bias voltage applied across it, thereby changing the resonant characteristics of the two irregularly shaped metal structures and enabling dynamic manipulation of the electromagnetic response of the electromagnetic waves.

[0038] like Figure 2The diagram shows the flowchart of a matrix generation algorithm with top-down connectivity. First, variables are initialized in the first iteration; the initial point is set to the first point in the top left corner, and a metal patch is laid, i.e., i = 1, P strat =1; the function rand(1,n) represents randomly generating an integer between 1 and n, where P represents the cutoff point. end Between 1 and n; function Create_patch(i,P) strat ,P end The representation of P in the i-th row is... strat and P end Create a continuous metal patch between columns; in subsequent iterations, randomly select a point from the previous column as the intermediate point P. mid At point P, between 1 and the midpoint mid The initial point P of this column is randomly determined from among the points. strat At the midpoint P mid The cutoff point P of this column is randomly determined between n and n. end At the initial point P strat With the cutoff point P end Create a continuous metal patch between rows; the iteration ends when the metal patch in row m is completed.

[0039] like Figure 3 The diagram shown illustrates the principle of a reconfigurable metasurface structure; the algorithm Create_patch(i,P) is used. strat ,P end A 1 / 4 metal patch is generated and symmetrically subjected to two tests to obtain the final metal patch. The structure of the metal patch is also a bias line, and a varactor diode is introduced between the two irregular metal patches. The metal patches are connected vertically, which can ensure that the external voltage source is applied to the two ends of the varactor diode on each unit of the metasurface, control its working state, and generate a 180° phase difference to achieve 1-bit phase encoding.

[0040] like Figure 4 As shown, (a) and (b) are schematic diagrams of the metasurface unit structure, geometric parameters, and corresponding two-dimensional matrices, respectively; the period of the metasurface unit structure is p = 10 mm; the period of the two-dimensional matrix unit is u = 0.5 mm; the interval between the two irregularly shaped metal patches is g = 1 mm; the thickness of the dielectric substrate layer is h = 2 mm; when the two-dimensional matrix unit is coded as "1", a metal patch is laid; when the code is "0", no metal patch is laid.

[0041] like Figure 5 The figure shows the simulation results of the electromagnetic response of the reconfigurable metasurface unit under different operating states of the varactor diode. It can be seen from the figure that when the frequency is 4.5 GHz, the reflection phase of the metasurface unit achieves a phase difference of approximately 180°, as shown below. Figure 5As shown in (a) of Figure (5), the reflection amplitude difference is within 1dB, as shown in (b) of Figure (5), which satisfies the phase modulation condition and can realize 1-bit phase encoding; the metasurface unit when the varactor diode capacitance C = 1.17pF is encoded as binary code "0", and the metasurface unit when the varactor diode capacitance C = 2.12pF is encoded as binary code "1".

[0042] like Figure 6 As shown, different coding sequences of the reconfigurable metasurface and the corresponding electromagnetic wave far-field patterns are presented. (a) and (b) are comparisons of different coding sequences of the metasurface, while (c) and (d) are electromagnetic wave far-field patterns corresponding to the coding sequences of (a) and (b), respectively. By coding the metasurface according to different coding sequences, the deflection angle of the electromagnetic wave reflected beam can be changed, thereby achieving the purpose of controlling the electromagnetic wave scattering mode, which verifies the feasibility and effectiveness of the structure.

[0043] The metal patch in this invention serves as both a structure and a bias line. The metal patch is interconnected vertically, and its operation can be controlled by an external voltage source to generate a 180° phase difference, achieving 1-bit phase encoding and enabling dynamic manipulation of electromagnetic wave responses. The integrated bias design offers unique lightning protection and de-icing capabilities, demonstrating strong practical applicability. Furthermore, the designed metasurface, when combined with an intelligent control terminal, can realize an intelligent metasurface system adaptable to various environments, showing broad application prospects in fields such as adaptive intelligent sensing.

[0044] This invention integrates the structure and bias line design on the same plane. The metal structure is also the bias line, which enables large-scale design of metasurfaces and improves the control performance of metasurfaces. It uses electrical control to change the working state of varactor diodes and dynamically manipulate the electromagnetic response of electromagnetic waves.

[0045] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A reconfigurable metasurface structure with a coplanar design of structure and bias line, characterized in that, include: Metal patch layer (1), active device (2), dielectric substrate layer (3) and reflective backplate layer (4); The metal patch layer (1) includes two symmetrically arranged and irregularly shaped metal structures, which are plated on the top surface of the dielectric substrate layer (3); an active device (2) is embedded between the two irregularly shaped metal structures, and the active device (2) is a varactor diode; the reflective backplate layer (4) is disposed on the bottom surface of the dielectric substrate layer (3). The irregularly shaped metal structure is composed of multiple interconnected metal patches, and the metal structure is discretized into offset lines; The metal patch layer (1) consists of two symmetrical metal structures that are discretized into irregular shapes and represented by a 0-1 two-dimensional matrix. When the two-dimensional matrix unit is encoded as "1", a metal patch is laid; when the unit is encoded as "0", no metal patch is laid. The metal patch layer (1) is created using the algorithm Create_patch( i , P strat , P end ) generates; among which, the function Create_patch( i , P strat , P end ), in the second plane i OK P strat and P end A continuous metal patch structure is created between columns, and the continuous metal patch structure is symmetrical from top to bottom to form a discrete metal structure of irregular shape. Then, the generated discrete metal structure of irregular shape is symmetrical from left to right to form a metal patch layer (1). in, i It is a natural number; P strat The initial point of the two-dimensional plane is set as the metal patch at the first point of the upper left corner of the two-dimensional plane; P end Metal patch representing the cutoff point of a two-dimensional plane; By changing the bias voltage applied across the varactor diode, the capacitance of the varactor diode is altered, which is used to change the resonant characteristics of an irregularly shaped metal structure discrete as bias lines.

2. The reconfigurable metasurface structure with a coplanar design of structure and bias line according to claim 1, characterized in that, The irregularly shaped metal structure is made of copper and is plated on the top surface of the dielectric substrate layer (3) using a printed circuit board.

3. The reconfigurable metasurface structure with a coplanar design of structure and bias line according to claim 1, characterized in that, The active device (2) is an SMV1405-079LF varactor diode; The varactor diode and the two irregularly shaped metal structures are equivalent to a series circuit containing a resistor, an inductor, and a capacitor, with a resistance of 0.8Ω and an inductance of 0.7nH. When the bias voltage applied to the varactor diode changes from 30V to 0V, the capacitance changes from 0.63pF to 2.67pF.

4. The reconfigurable metasurface structure with a coplanar design of structure and bias line according to claim 1, characterized in that, The dielectric substrate layer (3) is made of polytetrafluoroethylene (PTFE) plate F4B, and its dielectric constant is _____. The loss tangent is It is used to adjust the impedance of metasurface structures and change the amplitude and phase of incident electromagnetic waves.

5. A reconfigurable metasurface structure with a coplanar design of structure and bias line according to claim 1, characterized in that, The reflective backplate layer (4) is made of copper plate and is used to reflect incident electromagnetic waves.

6. A reconfigurable metasurface structure with a coplanar design of structure and bias line according to claim 1, characterized in that, When the frequency of the electromagnetic wave incident on the metasurface is 4.5 GHz, the metasurface structure achieves a 180° phase difference in reflection phase and a 1 dB amplitude difference in reflection amplitude.

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