2bit reconfigurable intelligent metasurface with electromagnetic energy dynamic amplification and signal filtering functions

Abstract

The invention discloses a 2bit reconfigurable intelligent metasurface with electromagnetic signal amplifying and filtering functions, and belongs to the field of communication and novel artificial electromagnetic materials. The metasurface comprises a metal patch layer, an FR4 dielectric layer, a metal gap layer, a microstrip circuit layer, a metal backboard layer and other multi-layer structures, broadband impedance matching is achieved through an hourglass type gap, and electromagnetic energy dynamic amplification, signal filtering and 2-bit phase regulation and control are achieved by loading a radio frequency circuit and a phase shifter structure. The microstrip circuit layer integrates a power distribution and synthesis network, the number of radio frequency devices is significantly reduced, and the system cost and power consumption are reduced. In the S wave band (2.8-3.2 GHz), the reflection coefficient of the metasurface is maximally improved by 15 dB, the phase regulation and control precision reaches 2 bits (90-degree phase difference), and dynamic beam forming and flexible scanning in the range of + / -30 degrees are supported. The invention solves the problems of narrow bandwidth, large in-band loss, serious out-of-band interference and high hardware cost in the prior art, and is suitable for intelligent relay and signal enhancement scenes in a sixth generation mobile communication system.

Description

Technical Field

[0001] The present invention relates to a technology for dynamic electromagnetic wave energy amplification, signal filtering and 2-bit phase regulation based on a broadband reflective reconfigurable intelligent metasurface structure with a loadable radio frequency circuit and a phase shifter structure, which is used to realize dynamic electromagnetic wave signal energy amplification, signal filtering and 2-bit phase regulation within a broadband range. At the same time, by introducing a power distribution network and a power synthesis network, the use of radio frequency devices can be greatly reduced, thereby reducing system cost and power consumption. The present invention belongs to the field of communications and new artificial electromagnetic materials. Background Art

[0002] In recent years, the fifth generation of mobile communication (5G) networks have been successfully deployed in more than a dozen countries, prompting researchers to gradually shift their research focus to the development of the sixth generation of mobile communication (6G) networks. With the increasing demand for ubiquitous wireless connectivity driven by the Internet of Things (IoT) technology, the demand for higher system capacity in 6G networks has also increased significantly. At the same time, the surge in the number of access devices has brought urgent challenges to enhance signal strength, ensure communication quality, and solve energy consumption problems. Among the many potential 6G technical solutions, the ultra-large-scale multiple-input multiple-output (MIMO) system significantly enhances the signal coverage within the cell by utilizing high-gain antenna arrays. However, due to the influence of buildings, plants and other obstacles, there are still signal blind spots in the entire cell area, which affects the smoothness of user experience. To solve this problem, the industry has introduced equipment such as wireless relays and repeaters to enhance the signal strength of these blind spots and improve communication quality. However, traditional wireless relay equipment is difficult to meet the requirements of 6G communication systems due to its high cost, high energy consumption and complex architecture. At the same time, although the cost of repeaters is low, they cannot achieve beamforming, and sometimes their omnidirectional coverage increases interference within the cell, resulting in complex communication network planning.

[0003] To address these issues, reconfigurable smart metasurfaces have attracted widespread attention due to their unique properties of low cost, low energy consumption, and simple architecture. Typically, a reconfigurable smart metasurface consists of a large number of carefully designed periodic structures loaded with adjustable elements, such as switching diodes and varactor diodes. By dynamically controlling these adjustable elements through a microcontroller unit (MCU) or a field programmable gate array (FPGA), reconfigurable smart metasurfaces can control all the basic properties of electromagnetic (EM) waves in real time, including amplitude, phase, polarization, frequency, and wave vector.

[0004] With its excellent electromagnetic control performance, reconfigurable intelligent metasurfaces are widely used to build flexible and controlled electromagnetic environments. It can be deployed in outdoor or indoor environments, and combined with existing transceivers to achieve joint optimization of wireless channels, thereby reshaping the wireless channel environment, improving the signal-to-noise ratio, and enhancing signal coverage. Therefore, reconfigurable intelligent metasurfaces provide a promising, efficient and simple wireless relay capability for the upcoming 6G communication system.

[0005] However, the effectiveness of this technology is sometimes affected by the attenuation of the relay link path loss, which is caused by the significant reduction of the material interface scattering energy due to the non-negligible loss of the adjustable elements in the metasurface. Therefore, a larger metasurface array is usually required to increase the array gain to ensure sufficient signal strength, which will lead to increased hardware costs. To alleviate this problem, reconfigurable smart metasurfaces with electromagnetic wave energy amplification function have emerged. However, most of the existing reconfigurable smart metasurfaces work in a narrow band and lack dynamic amplitude and phase adjustment capabilities, which restricts their beamforming capabilities and limits their application in communication systems. At the same time, considering the potential spectrum pollution problem, the existing reconfigurable smart metasurfaces not only manipulate signals within the required frequency range, but also affect signals outside this range, resulting in serious network interference problems or potential security risks. Metasurfaces with electromagnetic wave amplification capabilities even enhance these undesirable out-of-band signals, which may lead to further deterioration of the entire communication system. It should be pointed out that these reconfigurable smart metasurfaces with electromagnetic energy amplification functions are usually equipped with an active amplifier device for each unit, which leads to higher hardware costs and power losses. The above combined factors will greatly limit the further application of reconfigurable smart metasurfaces in the new generation of mobile communication networks.

[0006] Based on this, we need to design a broadband reconfigurable intelligent metasurface with the ability to dynamically amplify electromagnetic energy, signal filtering function, and phase control, while minimizing the use of active RF devices to reduce costs and power consumption. Summary of the invention

[0007] Purpose of the invention: In order to achieve in-band dynamic enhancement and out-of-band suppression of electromagnetic wave energy and dynamic regulation of electromagnetic wave phase within a broadband range, the present invention provides a broadband reconfigurable intelligent metasurface structure with electromagnetic energy dynamic amplification capability, signal filtering function and phase regulation, which can realize reception of incident electromagnetic waves, dynamic energy amplification, signal filtering, 2-bit phase regulation and re-radiation, and at the same time introduce power distribution and power synthesis networks, so that the reconfigurable intelligent metasurface structure can ensure the existing functions and significantly reduce the use of radio frequency devices to reduce system costs and power consumption.

[0008] Technical solution: To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a broadband reflective reconfigurable intelligent metasurface structure that can be loaded with radio frequency circuits and phase shifter structures, the reconfigurable intelligent metasurface structure includes a metal patch layer, an FR4 dielectric layer, an air dielectric layer, a metal gap layer, a Ro4350B dielectric layer, a microstrip circuit layer, an air dielectric layer and a metal backplane layer. The metal gap layer includes an hourglass-shaped gap structure for realizing broadband coupling of electromagnetic energy between the metal patch layer and the microstrip circuit layer. The microstrip circuit layer integrates radio frequency circuits, phase shifter structures, power distribution networks and power synthesis networks, wherein: the radio frequency circuit is used to realize in-band dynamic amplification of electromagnetic energy and out-of-band signal filtering; the phase shifter structure realizes 2-bit phase regulation by controlling the electromagnetic wave transmission path; the power distribution and synthesis network reduces the number of radio frequency devices, and reduces system cost and power consumption. The hourglass-shaped gap structure includes paired longitudinal and transverse hourglass-shaped gaps.

[0009] The smart metasurface uses metal patches etched on the FR4 medium to receive x-polarized electromagnetic waves, and couples the energy to the longitudinal hourglass-shaped gaps of the metal gap layer through the air dielectric layer. The electromagnetic energy is then further coupled to the microstrip line branches of the microstrip circuit layer through the Ro4350B dielectric layer, and is aggregated to the microstrip line main branch through the power synthesis network. The electromagnetic signal on the microstrip line main branch realizes the dynamic amplification of in-band energy and the filtering of out-of-band signals through the loaded RF circuit. The amplified and filtered electromagnetic energy is distributed to each microstrip line branch through the power distribution network, and then the 2-bit phase dynamic control is realized through the corresponding phase shifter structure. Finally, it is coupled to the transverse hourglass-shaped gap of the metal gap layer through the Ro4350B dielectric layer. The energy is further coupled to the metal patch layer etched on the FR4 substrate through the air dielectric layer again, and is re-radiated in the form of y polarization.

[0010] A broadband reconfigurable intelligent metasurface structure loaded with radio frequency circuits and phase shifter structures is used to realize reception, energy amplification, signal filtering, phase control and reradiation of electromagnetic waves in a broadband range, thereby realizing dynamic in-band energy amplification, out-of-band energy filtering and dynamic signal phase control of electromagnetic waves in a broadband range.

[0011] Preferably, the longitudinal gap sizes are: a1 = 6.4 mm, a2 = 1.3 mm, a3 = 8.0 mm, a4 = 0.9 mm;

[0012] Horizontal gap dimensions: b1=5.8mm, b2=12.1mm, b3=15.4mm, b4=5.7mm, b5=12.6mm, b6=17.5mm.

[0013] Preferably, the phase shifter structure realizes phase control by switching the electromagnetic wave transmission path, specifically including:

[0014] Path A and path B are controlled to achieve a 90° phase difference;

[0015] Path C and path D are controlled to achieve a 180° phase difference.

[0016] Preferably, the microstrip line structural parameters of the power distribution and synthesis network are:

[0017] R1=8.00mm, R2=8.90mm, W1=1.65mm, W2=1.35mm, W3=0.40mm, W4=0.99mm, W5=0.57mm, W6=0.94mm, W7=0.73mm, W8=0.89mm.

[0018] Preferably, the metal patch layer is composed of a 1×8 array of metal patches, the size of a single patch is 30.87 mm×30.87 mm, and the distance between adjacent patches is 66 mm.

[0019] Preferably, the metasurface achieves a maximum electromagnetic energy amplification of 15dB in the 2.8-3.2GHz frequency band, out-of-band signal suppression is better than -20dB, and the phase control accuracy is 2bit.

[0020] Preferably, the metasurface controls the phase shifter state through FPGA, supports dynamic beamforming and beam scanning within the range of ±30°, and the switching delay is less than 10μs.

[0021] Preferably, the thickness of each layer is: 1 mm for FR4 dielectric layer, 7.5 mm for air dielectric layer, 0.762 mm for Ro4350B dielectric layer, and 1 mm for metal backplane layer.

[0022] The present invention also provides a dynamic beam control method based on the smart metasurface, comprising the following steps:

[0023] coupling the incident electromagnetic wave to the microstrip circuit layer through the hourglass-shaped gap;

[0024] Using radio frequency circuits to perform in-band energy amplification and out-of-band filtering;

[0025] 2-bit phase control is achieved through the phase shifter structure;

[0026] The signal is recoupled to the metal patch layer through the power distribution network to complete dynamic beamforming.

[0027] Preferably, the beamforming includes reflection gain control in directions of 0°, 10°, 20°, and 30°, and the main lobe gain is above 15 dB.

[0028] Beneficial effects: Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0029] 1. The present invention has successfully expanded the working bandwidth of the reflective intelligent metasurface by rationally designing the thickness of each layer and the shape of the gap of the metal gap layer. By loading the radio frequency circuit, it can realize the in-band energy enhancement, out-of-band signal filtering and phase dynamic control of electromagnetic signals within a broadband range, so that the communication signal can be flexibly beamformed and dynamically energy enhanced. In summary, the present invention, as a new type of relay device, can greatly improve the signal quality of communication and reduce crosstalk between spectrums.

[0030] 2. The present invention can greatly reduce the use of radio frequency devices by introducing a power distribution network and a power synthesis network. This design can greatly reduce the cost and power consumption of the system based on the smart metasurface, making it possible to widely use and popularize reconfigurable smart metasurfaces with dynamic beamforming that can amplify electromagnetic energy and filter signal.

[0031] 3. Traditional reconfigurable smart metasurfaces need to increase the array to improve signal strength due to component loss, which greatly increases the system hardware cost. Although the reconfigurable smart metasurface with amplification function solves some problems, it is limited by narrowband operation and lacks dynamic adjustment capabilities, and is prone to spectrum pollution and high hardware costs. These problems limit their further application in the next generation of communication systems. The reconfigurable smart metasurface of the present invention has the characteristics of broadband operation, and can realize electromagnetic energy amplification, signal filtering and dynamic phase control in a broadband range by loading radio frequency circuits and phase shifter structures. On this basis, the structure greatly reduces the use of radio frequency devices by introducing a power distribution network and a power synthesis network. Combined with the above, this makes it possible to design a low-cost, low-power broadband reconfigurable smart metasurface with electromagnetic wave amplification and filtering and dynamic phase control. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of a broadband reconfigurable intelligent metasurface structure based on a loaded RF device and a phase shifter structure. The structure shown includes a metal patch layer, an F4B dielectric layer, a metal gap layer, a Ro4350B dielectric layer, a microstrip circuit layer, an air dielectric layer and a metal backplane layer.

[0033] Figure 2The figure is a diagram of the overall structure of the microstrip circuit layer and the metal gap layer and their related distribution structures. Among them, (a) is a schematic diagram of the overall structure of the microstrip circuit layer and the metal gap layer, which includes a power synthesis network and a power distribution network, a radio frequency circuit including an amplifier and a filter, and a related phase shifter structure. (b) is a schematic diagram of the specific structure of a pair of metal gaps, which includes a longitudinal hourglass-shaped gap and a transverse hourglass-shaped gap. The entire metal gap layer contains 8 pairs of such metal gaps. (c) is a specific structural diagram of the phase shifter. The entire reconfigurable intelligent metasurface contains 8 such phase shifter structures. (d) is a specific structural diagram of the power synthesis and power distribution network.

[0034] Figure 3 It is the dynamic reflection gain diagram of the broadband reconfigurable smart metasurface at different reflection angles.

[0035] Figure 4 It is the 2-bit phase response diagram of the broadband reconfigurable smart metasurface.

[0036] Figure 5 It is the scattering pattern of the broadband reconfigurable smart metasurface. DETAILED DESCRIPTION

[0037] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0038] One embodiment of the present invention is as follows Figure 1 As shown, the broadband reflective intelligent metasurface structure based on the loading amplifier is composed of a metal patch layer, a FR4 dielectric layer, an air dielectric layer, a metal gap layer, a Ro4350B dielectric layer, a microstrip circuit layer, an air dielectric layer and a metal backplane layer, wherein the thickness of each layer structure is 0.018mm, 1mm, 7.5mm, 0.018mm, 0.762mm, 0.018mm, 30mm, and 1mm, respectively. The overall manufacturing process of the structure is as follows: first, a FR4 medium is selected and a metal patch layer is printed on it using a printed circuit board process. The metal patch layer is composed of 1*8 metal patches, wherein the size of a single metal patch is 30.87mm*30.87mm, and the spacing between two adjacent metal patches is 66mm. Subsequently, a Ro4350B medium is selected and a metal gap layer and a microstrip circuit layer are printed on the front and back of the medium using a printed circuit board process, respectively. Finally, a metal patch layer is placed in front of the metal gap layer with a suitable air dielectric layer by using screw bolting technology, and a metal backplane is loaded at a position with a suitable air dielectric layer behind the microstrip circuit layer.

[0039] The overall structure of the F4B dielectric layer, microstrip circuit layer and metal gap layer and their related distribution structure are shown in the figure. Figure 2 As shown in (a), the electromagnetic wave energy is coupled to the power synthesis network through the metal gap, and then enters the amplifier circuit and filter circuit in the loaded RF circuit to realize dynamic energy amplification and signal filtering of the electromagnetic wave, and then passes through the power distribution network to enter the corresponding phase shifter structure to realize dynamic phase regulation, and finally re-coupled to the metal patch through the corresponding metal gap to realize energy re-radiation.

[0040] The metal gap structure is as follows Figure 2 As shown in (b), two hourglass-shaped slot structures are distributed in pairs in the form of 1*8 on the metal slot layer for coupling electromagnetic energy between the metal patch layer and the microstrip circuit layer. The hourglass-shaped slot structure can effectively expand the working bandwidth of the smart metasurface. The structural parameters of the transverse hourglass-shaped slot and the longitudinal hourglass-shaped slot are: a1=6.4mm, a2=1.3mm, a3=8.0mm, a4=0.9mm, b1=5.8mm, b2=12.1mm, b3=15.4mm, b4=5.7mm, b5=12.6mm, b6=17.5mm.

[0041] The specific structure of the phase shifter is as follows: Figure 2 As shown in (c), the phase shifter structure is distributed in the form of 1*8 on the microstrip circuit layer and placed in the last stage of the power distribution network to achieve phase control of the electromagnetic wave. The specific implementation method is to control the path of the electromagnetic wave through a DC bias circuit to achieve different phase differences. When the electromagnetic wave is controlled to pass through path A and path B respectively, a 90° phase difference is achieved, and when the electromagnetic wave is controlled to pass through path C and path D respectively, a 180° phase difference can be achieved. In summary, the phase shifter structure can achieve 2-bit phase control.

[0042] The power synthesis and power distribution network is as follows: Figure 2 As shown in (d), it mainly includes 8 microstrip line branch structures, and its related structural parameters are: R1 = 8.00mm, R2 = 8.90mm, W1 = 1.65mm, W2 = 1.35mm, W3 = 0.40mm, W4 = 0.99mm, W5 = 0.57mm, W6 = 0.94mm, W7 = 0.73mm, W8 = 0.89mm.

[0043] The dynamic reflection gain diagram of the reconfigurable intelligent metasurface under different reflection angles is shown in FIG. Figure 3As shown. It can be seen from the figure that the reconfigurable intelligent reflective metasurface can reflect electromagnetic waves in the directions of 0°, 10°, 20°, and 30°, while achieving a maximum energy amplification of more than 15dB at 2.8-3.2GHz. By adjusting the control voltage of the RF circuit. The reconfigurable intelligent metasurface can achieve dynamic regulation of the energy dynamic amplitude of more than 25dB within the band. At the same time, it can also be seen from the figure that the metasurface effectively suppresses out-of-band signals and realizes the function of signal filtering. The dynamic phase response of the reconfigurable intelligent metasurface is as follows Figure 4 As shown in the figure, it can be seen that the metasurface effectively realizes the 2-bit dynamic control of the phase of the reflected electromagnetic wave. Thanks to the phase control capability of the reconfigurable intelligent metasurface, it can achieve effective beamforming capability. Figure 5 The reconfigurable intelligent metasurface can effectively control the scattering pattern and achieve flexible beamforming from -30° to +30°.

[0044] The present invention proposes a method for dynamic amplification of electromagnetic energy, signal filtering and dynamic phase control based on a broadband reconfigurable intelligent metasurface structure loaded with a radio frequency circuit and a phase shifter structure. The method realizes reception, energy amplification, signal filtering, phase control and re-radiation of electromagnetic waves in a broadband range to realize in-band dynamic amplification and out-of-band filtering and phase control of the reflected energy of electromagnetic waves in a broadband range by using a broadband reconfigurable intelligent metasurface structure loaded with a radio frequency circuit and a phase shifter structure. The principles of dynamic amplification of electromagnetic waves, signal filtering and dynamic phase control of the broadband intelligent reconfigurable metasurface designed by the present invention are as follows: The intelligent metasurface receives x-polarized electromagnetic waves using a metal patch layer, and couples the energy to eight transverse hourglass-shaped metal gaps of the metal gap layer through an air dielectric layer. Subsequently, the electromagnetic energy is further coupled to each microstrip line branch corresponding to the power synthesis network of the microstrip circuit layer through the Ro4350B dielectric layer, and is aggregated to the main microstrip line branch through the power synthesis network. The electromagnetic energy on the main branch of the microstrip line is dynamically amplified and signal filtered through the loaded radio frequency circuit, and then distributed to the corresponding microstrip line branches through the power distribution network and the phase of the electromagnetic wave is dynamically controlled through the corresponding phase shifter structure, and then coupled to the eight longitudinal hourglass-shaped slots of the metal slot layer through the Ro4350B dielectric layer. The electromagnetic wave passes through the air dielectric layer again, is further coupled to the metal patch layer, and is re-radiated by y polarization. Through the above method, the intelligent metasurface can effectively realize the in-band dynamic enhancement and out-of-band filtering of electromagnetic energy and dynamic phase control within a broadband range, and by introducing a power distribution network and a power synthesis network, the use of radio frequency devices can be greatly reduced, thereby greatly reducing the cost and power consumption of the system based on the intelligent metasurface.

[0045] The above descriptions are only some embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A 2-bit reconfigurable smart metasurface with electromagnetic signal amplification and filtering functions, characterized in that: include: The metal patch layer, FR4 dielectric layer, air dielectric layer, metal gap layer, Ro4350B dielectric layer, microstrip circuit layer, air dielectric layer and metal backplane layer are stacked in sequence; The metal gap layer comprises an hourglass-shaped gap structure for realizing broadband coupling of electromagnetic energy between the metal patch layer and the microstrip circuit layer; The microstrip circuit layer integrates a radio frequency circuit, a phase shifter structure, a power distribution network and a power synthesis network, wherein: The radio frequency circuit is used to realize the in-band dynamic amplification of electromagnetic energy and out-band signal filtering; The phase shifter structure achieves 2-bit phase control (90° phase difference) by controlling the electromagnetic wave transmission path; The power distribution and synthesis network reduces the number of RF components, lowering system cost and power consumption.

2. The smart supersurface according to claim 1, characterized in that: The hourglass-shaped gap structure includes a pair of longitudinal and transverse hourglass-shaped gaps, and its structural parameters are: Longitudinal gap size: a1 = 6.4 mm, a2 = 1.3 mm, a3 = 8.0 mm, a4 = 0.9 mm; Horizontal gap dimensions: b1=5.8mm, b2=12.1mm, b3=15.4mm, b4=5.7mm, b5=12.6mm, b6=17.5mm.

3. The smart supersurface according to claim 1, characterized in that: The phase shifter structure realizes phase control by switching the electromagnetic wave transmission path, specifically including: Path A and path B are controlled to achieve a 90° phase difference; Path C and path D are controlled to achieve a 180° phase difference.

4. The smart supersurface according to claim 1, characterized in that: The microstrip line structure parameters of the power distribution and synthesis network are: R1=8.00mm, R2=8.90mm, W1=1.65mm, W2=1.35mm, W3=0.40mm, W4=0.99mm, W5=0.57mm, W6=0.94mm, W7=0.73mm, W8=0.89mm.

5. The smart supersurface according to claim 1, characterized in that: The metal patch layer is composed of 1×8 array metal patches, the size of a single patch is 30.87 mm×30.87 mm, and the distance between adjacent patches is 66 mm.

6. The smart supersurface according to claim 1, characterized in that: The metasurface achieves a maximum electromagnetic energy amplification of 15dB in the 2.8-3.2GHz frequency band, out-of-band signal suppression better than -20dB, and a phase control accuracy of 2bit.

7. The smart supersurface according to claim 1, characterized in that: The metasurface controls the phase shifter state through FPGA, supports dynamic beamforming and beam scanning within the range of ±30°, and the switching delay is less than 10μs.

8. The smart supersurface according to claim 1, characterized in that: The thickness of each layer is: FR4 dielectric layer 1mm, air dielectric layer 7.5mm, Ro4350B dielectric layer 0.762mm, and metal backplane layer 1mm.

9. A dynamic beam control method based on the smart metasurface according to any one of claims 1 to 8, characterized in that: The following steps are involved: coupling the incident electromagnetic wave to the microstrip circuit layer through the hourglass-shaped gap; Using radio frequency circuits to perform in-band energy amplification and out-of-band filtering; 2-bit phase control is achieved through the phase shifter structure; The signal is recoupled to the metal patch layer through the power distribution network to complete dynamic beamforming.

10. The method according to claim 9, characterized in that The beamforming includes enhanced control of reflected energy in directions of 0°, 10°, 20°, and 30°, and the main lobe energy is enhanced by more than 15 dB.

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