A low-profile reconfigurable smart metasurface with dual-band 3-bit independent coding

Abstract

The present invention discloses a low-profile, reconfigurable intelligent metasurface with dual-band, 3-bit independent encoding. The intelligent metasurface comprises n basic units arranged in a matrix, with each column of units forming a subarray. The subarrays are controlled by two independent DC feeders, and each subarray is provided with a control signal by a control circuit. In the present invention, two varactor diodes are introduced into each unit to form two tunable resonant structures, both of which are located on the same metal layer. This allows the phase of reflected waves incident on the two frequency bands of the present invention to achieve independent, continuous, and wide-margin dynamic adjustment ranges without increasing the profile of the intelligent metasurface.

Description

Technical Field

[0001] The present invention relates to the technical field of reconfigurable intelligent metasurfaces, and in particular to a low-profile reconfigurable intelligent metasurface with dual-band 3-bit independent coding. Background Art

[0002] Future wireless communications will increasingly demand faster, more efficient, and more stable communications. Reconfigurable smart metasurfaces, with their ability to flexibly manipulate electromagnetic waves, are widely considered by academia and industry to be one of the most promising cutting-edge technologies for the next generation of mobile communications. Dual-band reconfigurable smart metasurfaces can achieve aperture sharing across two frequency bands, improving spectrum utilization in wireless communication environments and thus expanding communication capacity. However, existing dual-band reconfigurable smart metasurfaces lack the ability to independently control the phase of the two frequency bands, significantly limiting their practical use. Alternatively, they rely on multi-layer structures with high cross-sections, significantly impacting their commercial applications. Summary of the Invention

[0003] Technical problem: In view of this, the purpose of the present invention is to provide a low-profile reconfigurable intelligent metasurface with dual-band 3-bit independent encoding to solve the technical problems mentioned in the background technology.

[0004] Technical solution: To achieve the above objectives, the present invention adopts a dual-band 3-bit independently encoded low-profile reconfigurable smart metasurface comprising:

[0005] n basic units are arranged in a matrix, where each column of units forms a sub-array, which is controlled by two independent DC feeders, and each sub-array is provided with a control signal by a control circuit;

[0006] The basic unit includes, from top to bottom:

[0007] The first layer is a metal layer, which is composed of a first varactor connected in series with a first metal patch and a second metal patch, and a second varactor connected in series with a third metal patch and a fourth metal patch, forming two resonant structures with different frequencies;

[0008] The second layer is a first dielectric substrate;

[0009] The third layer is the metal back plate;

[0010] A first metal through-hole row and a second metal through-hole row are provided between the metal layer of the first layer and the metal backplate of the third layer; the first metal patch and the third metal patch are connected to the metal backplate of the third layer by the first metal through-hole and the third metal through-hole, providing a DC ground for controlling the first varactor and the second varactor;

[0011] The fourth layer is a second dielectric substrate;

[0012] The fifth layer is the DC feeder layer, which consists of two narrow metal wires forming the DC feeder;

[0013] The metal patch and the fourth metal patch of the first layer are connected to the DC feeder of the fifth layer via the second metal through-hole and the fourth metal through-hole, providing control lines for the first varactor and the second varactor.

[0014] The planar structure of the basic unit includes a first dielectric substrate, with a first metal patch, a second metal patch, a third metal patch, and a fourth metal patch symmetrically arranged at the center of the upper surface of the first dielectric substrate. A first varactor is connected between the first and second metal patches, and a second varactor is connected between the third and fourth metal patches. A first metal through-hole is arranged inside the first metal patch, a second metal through-hole is arranged inside the second metal patch, a third metal through-hole is arranged inside the third metal patch, and a fourth metal through-hole is arranged inside the fourth metal patch. A first metal through-hole row is arranged outside the first and third metal patches, and a second metal through-hole row is arranged outside the second and fourth metal patches.

[0015] The varactor diode generates a capacitance change of 0.6 to 2.6 pF when the reverse feeding voltage changes from 0 to 30 V.

[0016] The varactor diode has a phase variation range of more than 320° when the electromagnetic wave is reflected back in two frequency bands under different control voltages.

[0017] The different control voltages specifically include: 2.52-2.67GHz frequency band: 0V, -1.8V, -2.5V, -3V, -3.5V, -4V, -5.5V, -30V, 3.4-3.5GHz frequency band: 0V, -4V, -6V, -7V, -8V, -9V, -12V, -30V.

[0018] Beneficial effects: The dual-band 3-bit independently encoded low-profile reconfigurable smart metasurface of the present invention has the following advantages:

[0019] 1. The principle of the present invention is simple. By simply changing the reverse bias voltage on different varactor diodes, the reflected waves of electromagnetic waves incident on the corresponding frequency band of the present invention can be regulated in real time, continuously, dynamically and independently without affecting other frequency bands.

[0020] 2. The present invention designs two tunable resonant structures on the same metal layer, which has a low profile and is easy to commercialize.

[0021] 3. The present invention combines multiple basic units into a basic sub-array, which is controlled by two independent signals. This can reduce the interference caused by different boundaries on the unit reflection coefficient, and also reduce the complexity of the feed network design. Accordingly, compared with the existing technology, the present invention can obtain low-loss, high-bit coding phase control. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A top view of the dual-band reconfigurable smart metasurface provided in Example 1;

[0023] Figure 2 A side view of the dual-band reconfigurable smart metasurface provided in Example 1;

[0024] Figure 3 The simulation results of the dual-band reconfigurable smart metasurface provided in Example 1 are plotted as a function of frequency in two frequency bands. (a) and (c) are plotted as a function of amplitude, and (b) and (d) are plotted as a function of frequency.

[0025] Figure 4 These are the test results of the frequency-varying curve graph of the dual-band reconfigurable smart metasurface provided in Example 1 in two frequency bands, (a) and (c) are the test results of the amplitude-varying curve graph, and (b) and (d) are the test results of the phase-varying curve graph.

[0026] The figure shows: first dielectric substrate 1, first varactor 1.1, second varactor 1.2, first metal patch 1.3.1, second metal patch 1.3.2, third metal patch 1.3.3, fourth metal patch 1.3.4, first metal through-hole 1.4, second metal through-hole 1.5, third metal through-hole 1.6, fourth metal through-hole 1.7, metal backplane 1.8; second dielectric substrate 2, DC feeder 2.1, first metal through-hole row 3, second metal through-hole row 4. DETAILED DESCRIPTION

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0028] Example 1

[0029] See also Figure 1-Figure 4This embodiment provides a low-profile reconfigurable smart metasurface with dual-band 3-bit independent coding, specifically comprising: n basic units arranged in a matrix, wherein each column of units forms a subarray, wherein the subarray is controlled by two independent DC feeders 2.1, and each subarray is provided with a control signal by a control circuit.

[0030] The first layer is the metal layer, which is composed of varactor 1.1 and varactor 1.2 connected in series with metal patches 1.3.1 and 1.3.2 and metal patches 1.3.3 and 1.3.4, forming two resonant structures with different frequencies.

[0031] The second layer is a dielectric substrate 1;

[0032] The third layer is the metal backplane 1.8;

[0033] Among them, rows of metal through-holes 3 and 4 are arranged between the first layer and the third layer, and the metal patches 1.3.1 and metal patches 1.3.3 of the first layer are connected to the metal backplane 1.8 of the third layer by metal through-holes 1.4 and metal through-holes 1.6, providing a DC ground for the control of the varactor tubes 1.1 and 1.2.

[0034] The fourth layer is a dielectric substrate 2;

[0035] The fifth layer is the metal layer, which consists of two narrow metal wires forming the DC feed line 2.1.

[0036] The metal patches 1.3.2 and 1.3.4 of the first layer are connected to the DC feeder 2.1 of the fifth layer by metal through-holes 1.5 and 1.7, providing control lines for the varactor 1.1 and the varactor 1.2.

[0037] Furthermore, the varactor diode generates a capacitance change of 0.6 to 2.6 pF when the reverse feeding voltage changes from 0 to 30 V.

[0038] Furthermore, under different control voltages, the phase variation range of the electromagnetic wave back reflection exceeds 320° in two frequency bands.

[0039] Furthermore, the different control voltages specifically include: 2.52-2.67GHz frequency band: 0V, -1.8V, -2.5V, -3V, -3.5V, -4V, -5.5V, -30V, 3.4-3.5GHz frequency band: 0V, -4V, -6V, -7V, -8V, -9V, -12V, -30V.

[0040] Specifically: the first dielectric substrate is F4B dielectric board (ε r =2.65, tanδ=0.003), thickness is 3.3mm;

[0041] The second dielectric substrate is F4B dielectric board (ε r =2.65, tanδ=0.003), thickness is 0.2mm;

[0042] The surface copper layer is 0.035 μm thick and is mainly composed of two pairs of identical metal rectangular sheets;

[0043] The middle layer is a complete copper layer coated with 0.035μm thickness as the ground layer to realize the reflective reconfigurable smart metasurface;

[0044] The bottom layer is coated with a 0.035μm thick copper layer as a signal layer to achieve independent control of the states of the two varactors on each unit;

[0045] Varactor diode 1 is used to connect two smaller metal rectangular sheets on the top layer, while varactor diode 2 is used to connect two larger metal rectangular sheets on the top layer. These two varactors function as state-adjustable phase tuning devices. When reverse biased, the junction capacitance generated by the varactors changes with voltage. This characteristic enables varactors 1 and 2 to independently tune the phases of reflected electromagnetic waves with two different resonant frequencies. Each of the two varactors has two metal holes on either side: one connected to the middle metal layer (metal ground) and the other to the bottom metal layer (signal layer), providing the appropriate DC voltage required by the two varactors in a given state.

[0046] Specifically, if Figure 1-Figure 2 As shown, the dimensions marked in the basic unit in this embodiment are:

[0047] Px=39mm, Py=31mm, L1=16mm, L2=18mm, L3=18mm, L4=8.8mm, W1=10mm, W2=12.2mm, W3=1mm, W4=12.2mm,

[0048] This embodiment provides a dual-band 3-bit independently encoded low-profile reconfigurable smart metasurface. Under normal incidence of electromagnetic waves, the phases of the reflected waves of the two frequency bands incident on this embodiment can be independently controlled by changing the bias voltages on the two varactor diodes. Specifically:

[0049] For an N-bit coded smart metasurface, its initial phase is Then the phase of the nth state is This means that an N-bit coded intelligent metasurface must at least meet the requirements of 0-360°×(2 N -1) / 2 N The phase variation range can be adjusted to 360° / 2. N 2N phase states, more specifically:

[0050] For a 3-bit coded smart metasurface, the phase variation range should be 0 to 315°, and 8 phase states with an interval of 45° can be obtained.

[0051] Figure 3 and Figure 4 The simulation and test results of the reflection coefficient are given respectively. Figure 3 and Figure 4 (a) shows the magnitude of the reflection coefficient when operating in the 2.52-2.67 GHz band. Figure 3 and Figure 4 (b) shows the phase of the reflection coefficient when operating in the 2.52-2.67 GHz band. Figure 3 and Figure 4 (c) shows the magnitude of the reflection coefficient when operating in the 3.4-3.5 GHz band. Figure 3 and Figure 4 (b) shows the phase of the reflection coefficient when operating in the 3.4-3.5GHz band. Figure 3 and Figure 4 It can be seen that the reflection phases in the two working frequency bands can be independently controlled.

[0052] This embodiment also provides a specific testing method, which specifically includes:

[0053] Step S1: Place the transmitting antenna and the receiving antenna on both sides of the normal line of the reconfigurable smart metasurface provided in this embodiment, and the distance between them and the reconfigurable smart metasurface must be greater than 3m;

[0054] Step S2: applying a voltage source to the control circuit of the reconfigurable smart metasurface;

[0055] Step S3: The transmitting antenna and the receiving antenna are respectively connected to ports 1 and 2 of the vector network analyzer using radio frequency transmission lines;

[0056] Step S4, recording the amplitude and phase of the electromagnetic wave received under different control voltages;

[0057] Step S5: replacing the reconfigurable intelligent metasurface provided in this embodiment with a metal plate of the same size;

[0058] Step S6: Record the amplitude and phase of the received electromagnetic wave;

[0059] Step S7: Taking the amplitude and phase of the electromagnetic wave received when the metal plate is placed as a reference, the amplitude received at different voltages when the reconfigurable intelligent metasurface is placed is divided by the amplitude of the electromagnetic wave received when the metal plate is placed, and the relative amplitude received when the reconfigurable intelligent metasurface in this embodiment is placed at the corresponding voltage can be obtained. Correspondingly, the phase received at different voltages when the reconfigurable intelligent metasurface in this embodiment is subtracted from the phase of the electromagnetic wave received when the metal plate is placed, and the relative phase received when the reconfigurable intelligent metasurface is placed at the corresponding voltage can be obtained.

[0060] In summary, the present invention proposes a low-profile, reconfigurable smart metasurface with dual-band, 3-bit independent encoding. By introducing two varactor diodes into each unit to form two tunable resonant structures, both of which are located on the same metal layer, the phase of the reflected waves incident on the two frequency bands of the present invention can achieve an independent, continuous, and wide-margin dynamic adjustment range without increasing the profile of the smart metasurface. Overall, the low-profile, reconfigurable smart metasurface with dual-band, 3-bit independent encoding proposed in the present invention has significant practical application potential in wireless communication networks and next-generation wireless communication system architectures that utilize reconfigurable smart metasurfaces.

[0061] Anything not described in detail in the present invention is well known to those skilled in the art.

[0062] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A low-profile reconfigurable smart metasurface with dual-band 3-bit independent coding, characterized by: The intelligent metasurface comprises: n basic units arranged in a matrix, wherein each column of units forms a sub-array, the sub-array is controlled by two independent DC feeders (2.1), and each sub-array is provided with a control signal by a control circuit; The basic unit includes, from top to bottom: The first layer is a metal layer, which is composed of a first varactor (1.1) connected in series with a first metal patch (1.3.1) and a second metal patch (1.3.2), and a second varactor (1.2) connected in series with a third metal patch (1.3.3) and a fourth metal patch (1.3.4), forming two resonant structures with different frequencies; The second layer is a first dielectric substrate (1); The third layer is the metal back plate (1.8); A first metal through-hole row (3) and a second metal through-hole row (4) are provided between the metal layer of the first layer and the metal backplate (1.8) of the third layer; the first metal patch (1.3.1) and the third metal patch (1.3.3) are connected to the metal backplate (1.8) of the third layer via a first metal through-hole (1.4) and a third metal through-hole (1.6), providing a DC ground for controlling the first varactor (1.1) and the second varactor (1.2); The fourth layer is a second dielectric substrate (2); The fifth layer is the DC feeder layer, which consists of two narrow metal wires forming the DC feeder (2.1); The metal patch (1.3.2) and the fourth metal patch (1.3.4) of the first layer are connected to the DC feeder (2.1) of the fifth layer via a second metal through-hole (1.5) and a fourth metal through-hole (1.7), providing control lines for the first varactor (1.1) and the second varactor (1.2).

2. The low-profile reconfigurable smart metasurface with dual-band 3-bit independent coding according to claim 1, characterized in that: The planar structure of the basic unit comprises a first dielectric substrate (1); a first metal patch (1.3.1), a second metal patch (1.3.2), a third metal patch (1.3.3), and a fourth metal patch (1.3.4) are symmetrically arranged on the upper surface of the first dielectric substrate (1); a first varactor (1.1) is connected between the first metal patch (1.3.1) and the second metal patch (1.3.2); a second varactor (1.2) is connected between the third metal patch (1.3.3) and the fourth metal patch (1.3.4); A first metal through hole (1.4) is provided inside the metal patch (1.3.1), a second metal through hole (1.5) is provided inside the second metal patch (1.3.2), a third metal through hole (1.6) is provided inside the third metal patch (1.3.3), and a fourth metal through hole (1.7) is provided inside the fourth metal patch (1.3.4); a first metal through hole row (3) is provided on the outside of the first metal patch (1.3.1) and the third metal patch (1.3.3), and a second metal through hole row (4) is provided on the outside of the second metal patch (1.3.2) and the fourth metal patch (1.3.4).

3. The low-profile reconfigurable smart metasurface with dual-band 3-bit independent coding according to claim 2, characterized in that: The first varactor and the second varactor generate a capacitance change of 0.6-2.6 pF when the reverse feeding voltage changes from 0 to 30 V.

4. The dual-band 3-bit independently encoded low-profile reconfigurable smart metasurface according to claim 3, characterized in that: Under different control voltages, the first varactor and the second varactor have a phase variation range of more than 320° in two frequency bands when the electromagnetic wave is reflected backward.

5. The low-profile reconfigurable smart metasurface with dual-band 3-bit independent coding according to claim 4, characterized in that: The different control voltages specifically include: 2.52-2.67 GHz frequency band: 0V, -1.8V, -2.5V, -3V, -3.5V, -4V, -5.5V, -30V, 3.4-3.5 GHz frequency band: 0V, -4V, -6V, -7V, -8V, -9V, -12V, -30V.

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