Hybrid intelligent metasurface and array design method

Abstract

The invention discloses a hybrid intelligent metasurface and an array design method. The hybrid intelligent metasurface comprises a passive unit and an active unit, the passive unit comprises a metal radiation patch, a parasitic patch, a gap layer, a microstrip line layer, a foam layer, a metal floor, a first dielectric substrate and a second dielectric substrate; the metal radiation patch is arranged on the upper surface of the first dielectric substrate, and the parasitic patch is arranged on the lower surface of the first dielectric substrate; a foam layer is arranged between the first dielectric substrate and the second dielectric substrate; the upper surface of the second dielectric substrate is provided with a gap layer, and the lower surface is provided with a microstrip line layer. The metal floor is arranged below the second dielectric substrate; the metal radiation patches, the microstrip line layers and the parasitic patches of the active unit and the passive unit are different in structure, and the rest structures are the same. The defects that a traditional pure passive area is large and deployment is not easy are overcome, the defect that a full-active intelligent metasurface is high in power consumption is overcome, and the purposes of low power consumption and high gain are achieved.

Description

Technical Field

[0001] The present invention relates to the field of wireless communications, and in particular to a hybrid intelligent metasurface and an array design method. Background Art

[0002] With the commercial deployment of 5G systems, the industry has launched a wave of research and development in 6G communication technology. The goal of 6G communication technology is to achieve desired performance by shaping the radio propagation environment. Reconfigurable Intelligent Surfaces (RIS) can dynamically control electromagnetic properties such as the phase, amplitude, and polarization of electromagnetic waves. This allows them to alter channel characteristics during signal transmission, thereby improving the signal-to-noise ratio (SNR) of communication systems and, consequently, communication quality. Furthermore, RIS offers advantages such as low power consumption, low cost, and ease of deployment, making it considered a key 6G technology by the industry.

[0003] Smart metasurfaces can be divided into passive smart metasurfaces and active smart metasurfaces according to whether there are active devices in the electromagnetic wave control method. However, since the purely passive smart metasurface itself does not have the function of signal amplification, it is necessary to design a large number of independently controlled units to obtain high gain. This will result in the pure passive smart metasurface being bulky and the control circuit being extremely complex. To this end, the industry has proposed a fully active hybrid smart metasurface with signal amplification function. Although the fully active smart metasurface can achieve higher gain with a reduced aperture area, since active devices are integrated in each unit of the active smart metasurface, the power consumption and cost of the fully active smart metasurface are greatly increased.

[0004] Existing reports have systematically evaluated the theoretical benefits of hybrid smart metasurfaces primarily from the perspective of electromagnetic channel transmission, but have not truly realized hybrid smart metasurfaces at the hardware level. Therefore, realizing hybrid smart metasurfaces with high gain and low power consumption from a hardware perspective has great application value. Summary of the Invention

[0005] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the object of the present invention is to provide a hybrid intelligent metasurface and array design method.

[0006] Hybrid intelligent metasurface units can be divided into two forms: passive units and active units. Passive intelligent metasurface units are composed of a radiative metal layer, a reflective phase shifter based on a reconfigurable switching device, a dielectric substrate layer, and a metal floor. By independently controlling the switching state of the reconfigurable switching devices on the passive intelligent metasurface, dynamic phase control of electromagnetic waves in space is achieved. In order to facilitate the layout of the hybrid intelligent metasurface, the active unit needs to have the same size, structure, polarization mode, etc. as the passive unit. In addition to the phase control function, the active unit also has the function of signal amplification. The signal amplification function is achieved by an integrated power amplifier.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A hybrid smart metasurface comprising passive units and active units;

[0009] The passive unit includes a metal radiation patch, a parasitic patch, a gap layer, a microstrip line layer, a foam layer, a metal floor, a first dielectric substrate and a second dielectric substrate;

[0010] A metal radiation patch is provided on the upper surface of the first dielectric substrate, and a parasitic patch is provided on the lower surface thereof;

[0011] A foam layer is provided between the first dielectric substrate and the second dielectric substrate;

[0012] A slot layer is provided on the upper surface of the second dielectric substrate, and a microstrip line layer is provided on the lower surface thereof;

[0013] The metal floor is arranged below the second dielectric substrate;

[0014] The metal radiation patch, microstrip line layer and parasitic patch structures of the active unit and the passive unit are different, and the rest of the structures are the same.

[0015] Furthermore, the metal radiation patch of the passive unit is in a cross shape and is used to receive and radiate electromagnetic waves.

[0016] Furthermore, the parasitic patch of the passive unit is specifically a square patch, and four trapezoidal patches are arranged around the square patch.

[0017] Furthermore, the slot layer includes two orthogonally arranged I-shaped slots for energy coupling and row polarization conversion.

[0018] Furthermore, the metal radiation patch of the active unit is a metal patch with a cross-shaped gap etched therein.

[0019] Furthermore, the parasitic patch of the active unit is specifically a square patch, and a square patch is respectively provided at the four corners of the square patch.

[0020] Furthermore, the microstrip line layer in the active unit and the passive unit includes a reflective phase shifter, and the reflective phase shifter includes a reconfigurable device, and changing the switching state of the reconfigurable device changes the reflection phase of the active unit and the passive unit.

[0021] Furthermore, the microstrip line layer of the active unit includes a power amplifier for amplifying the signal.

[0022] Further, including:

[0023] Constructing the directional pattern function of hybrid smart metasurface;

[0024] Determining constraints of the hybrid smart metasurface;

[0025] And based on the constraint conditions, a constraint model of the hybrid metasurface pattern is obtained;

[0026] The constraint model is optimized based on a convex optimization algorithm to obtain the reflection coefficient matrix of the hybrid intelligent metasurface and determine the array form of the hybrid intelligent metasurface.

[0027] Furthermore, the directional pattern function of the hybrid intelligent metasurface is specifically:

[0028] Assuming that the hybrid smart metasurface array is an M×N array, its directional pattern is:

[0029]

[0030] Among them, E h (θ h ) is the radiation pattern of the feed horn antenna, k is the wave number, It is the mnth th The position vector of each cell, is the position vector of the feed horn antenna, is the observation direction, E unit (θ) is the mnth th The radiation pattern of each unit, It is the mnth th The phase of each unit, |Γ mn |mnth th The reflection coefficient of each unit is divided into the reflection coefficient of the passive unit |Γ for the hybrid intelligent metasurface. passive | and active unit reflection coefficient |Γ active |;

[0031] Rewrite it into matrix form: E(θ) = a(θ) T Γ

[0032] Among them, Γ and a(θ) T Expressed as:

[0033] Γ=[|Γ 11 |,...,|Γ MN |] T

[0034]

[0035] further,

[0036] The constraints include the gain of the hybrid intelligent metasurface and the number of active units. The optimized constraint model is:

[0037] min||G|| 1,2

[0038] stRe{|E (l) (θ max )|}=Re{|a (l) (θ max )Γ (l) |}≥α (l)

[0039] Among them, G(Γ (l) )=[g(Γ (1) ),...,g(Γ (L) )],g(Γ (l) ) represents the formation of the first th The array strategy coefficient when the directional pattern is (l) (θ max ) indicates the first th The gain when the directivity pattern is max Indicates the maximum scanning direction, α (l) is the given lth th The gain lower bound of the directional pattern.

[0040] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0041] (1) The present invention realizes a hybrid intelligent metasurface from the hardware level. Its passive and active units can achieve 1-bit phase control. In addition, the active unit can also realize the function of signal amplification. According to Shannon's theorem, the proposed passive and active units can realize the function of dynamically controlling the channel during the electromagnetic wave transmission process by controlling the phase and amplitude, which can improve the signal-to-noise ratio of the communication system and enhance the communication quality;

[0042] (2) The present invention proposes a hybrid intelligent metasurface array strategy to achieve maximum gain at the required scanning angle with a minimum number of active units.

[0043] (3) The hybrid intelligent metasurface proposed in the present invention overcomes the shortcomings of traditional purely passive metasurfaces, such as large area and difficulty in deployment, and the high power consumption of fully active metasurfaces, achieving the goal of low power consumption and high gain. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 An exploded diagram of the structure of a passive unit provided in an embodiment of the present invention;

[0046] Figure 2 A structural diagram of a passive unit provided in an embodiment of the present invention;

[0047] Figure 3 An exploded diagram of the structure of an active unit provided in an embodiment of the present invention;

[0048] Figure 4 A structural diagram of an active unit provided in an embodiment of the present invention;

[0049] Figure 5 A reflection phase curve of a passive unit in an on and off state provided in an embodiment of the present invention;

[0050] Figure 6 A reflection phase curve of an active unit in an on and off state provided in an embodiment of the present invention;

[0051] Figure 7 The following are reflection amplitude curves of a passive unit and an active unit in the on and off states provided in an embodiment of the present invention.

[0052] Figure 8 This is an 8×16 hybrid intelligent metasurface deployment strategy provided in an embodiment of the present invention.

[0053] The figure shows:

[0054] 1. First metal radiation patch, 2. First dielectric substrate, 3. Second metal parasitic patch, 4. First foam layer, 5. First gap layer, 6. Second dielectric substrate, 7. First metal floor, 8. First metal via, 9. First phase shifter, 10. First metal filter fan-shaped branch, 11. First inductor, 12. Reconfigurable switching device; 13. Third metal radiation patch, 14. Third dielectric substrate, 15. Fourth metal parasitic patch, 16. Second foam layer, 17. Second gap layer, 18. Fourth dielectric substrate, 19. Second metal floor, 20. Second metal via, 21. Second phase shifter, 22. Second metal filter fan-shaped branch, 23. Second inductor, 24. Reconfigurable switching device, 25. Power amplifier. DETAILED DESCRIPTION

[0055] The present invention will be further described in detail below with reference to the examples, but the embodiments of the present invention are not limited thereto.

[0056] Example

[0057] A hybrid intelligent metasurface comprises passive and active units. By manipulating the on and off states of the passive and active units, the phase of electromagnetic signals in space can be controlled. Furthermore, power amplifiers are integrated into the active units to enhance the signal amplitude.

[0058] Figure 1 Exploded diagram of the passive unit in the hybrid smart metasurface. Figure 2 This is the structural diagram of the passive unit.

[0059] The passive units include, from top to bottom:

[0060] The first layer structure includes a first metal radiation patch 1, whose function is to receive electromagnetic waves incident in space and radiate the phase-modulated electromagnetic waves into free space;

[0061] The second layer structure is a first dielectric substrate 2, and a first metal radiation patch 1 is placed on the upper surface of the first dielectric substrate 2;

[0062] The third layer is a second metal parasitic patch 3, which is used to adjust the matching and is placed on the lower surface of the first dielectric substrate 2;

[0063] The fourth layer is the first foam layer 4, which is used to adjust impedance matching and provide support, and is placed below the second metal parasitic patch 3;

[0064] The fifth layer structure is the first gap layer 5, which is placed below the first foam layer 4 and can realize the polarization conversion of electromagnetic waves; the gap layer includes two "I"-shaped gaps arranged orthogonally.

[0065] The sixth layer structure is the second dielectric substrate 6, which is placed below the first gap layer 5;

[0066] The seventh layer is a microstrip line layer, which consists of a first phase shifter 9, a first metal filter fan-shaped branch 10, and a first inductor 11. The first phase shifter 9 is a reflective phase shifter and includes a reconfigurable device 12. The positive electrode of the reconfigurable switch device 12 is connected to the first phase shifter 9, and the negative electrode is connected to the first metal floor 7 through a first metal via 8. By adjusting the on and off states of the reconfigurable switch device 12, the passive unit achieves 1-bit phase modulation. The first metal filter fan-shaped branch 10 and the first inductor 11 can isolate the RF signal from the DC signal, preventing the RF signal from affecting the DC signal.

[0067] The eighth structure layer is a first metal floor 7 , which is placed below the seventh structure layer and is used to reflect electromagnetic waves.

[0068] Further explanation: the first metal radiation patch 1 is cross-shaped, and the first parasitic patch is specifically a square patch, and four trapezoidal patches are arranged around the square patch.

[0069] Figure 3 Exploded diagram of the active unit in the hybrid smart metasurface. Figure 4 Figure 2 shows the structure of the active unit. To facilitate the realization of hybrid intelligent metasurfaces, the active unit's structural framework, dielectric substrate type and number of layers, number of metal layers, polarization direction, phase control, and other aspects should be the same as those of the passive unit.

[0070] The active unit includes:

[0071] The first layer structure includes a third metal radiation patch 13 for receiving and radiating electromagnetic waves;

[0072] The second layer structure includes a third dielectric substrate 14 , and the third metal radiation patch is disposed on the upper surface of the third dielectric substrate 14 .

[0073] The third layer structure is a fourth metal parasitic patch 15 , which can introduce a resonance point to adjust the bandwidth and matching of the active unit and is placed on the lower surface of the third dielectric substrate 14 .

[0074] The fourth layer structure is a second foam layer 16, which is placed below the fourth metal parasitic patch 15;

[0075] The fifth structure layer is the second gap layer 17, which is placed below the second foam layer 16;

[0076] The sixth layer structure is the fourth dielectric substrate 18, which is placed below the second gap layer 17;

[0077] The seventh layer is the microstrip line layer, consisting of a second phase shifter 21, a second metal filter branch 22, a second inductor 23, and a power amplifier 25. The second phase shifter 21 is a reflective phase shifter that includes a reconfigurable device 24. Controlling the on and off states of the reconfigurable device 24 enables dynamic phase control. By integrating the power amplifier 25, the active unit can achieve signal amplification.

[0078] The eighth layer structure is the second metal floor 19 .

[0079] Furthermore, the third metal radiation patch 13 is specifically a square metal patch, and a cross-shaped gap is etched in the middle of the square metal patch to better adjust the matching. The function of the metal radiation patch is to receive the incident electromagnetic wave and radiate the electromagnetic wave with phase shift and amplitude control.

[0080] Furthermore, the fourth metal parasitic patch is specifically four smaller square patches loaded around a square patch.

[0081] The phase shifter and power amplifier are both placed in the microstrip layer. The phase shifter controls the phase, while the power amplifier controls the amplitude.

[0082] Furthermore, to ensure the normal operation of the power amplifier, a bias circuit needs to be added as required.

[0083] Preferably, the metal layers used in the passive unit and the active unit are both copper foils with a thickness of 1 oz.

[0084] The simulated reflection phase characteristic curve of the designed passive intelligent metasurface is shown in Figure 5 As shown, it can be seen that the phase curves of the passive intelligent metasurface unit in the on and off states are well parallel, the unit phase difference is 180±20°, and the phase shift range is 4.9GHz-5.7GHz.

[0085] The simulated reflection phase characteristic curve of the designed active intelligent metasurface is shown in the figure below: Figure 6 As shown, it can be seen that the active intelligent metasurface unit can achieve 1-bit phase control at 4.8GHz-5.7GHz.

[0086] The reflection amplitude curves of the designed passive intelligent metasurface unit and active intelligent metasurface unit in the on and off states are shown in Figure 2. Figure 7 As shown in the figure, the passive unit has a reflection loss of less than 3dB within the operating frequency band. Meanwhile, the reflection amplitude of the active unit at 5.2GHz is 14.9dB, which is about 15dB higher than that of the passive unit. It can be seen that the active unit significantly amplifies the electromagnetic wave.

[0087] This embodiment also provides a hybrid intelligent metasurface array design method, including:

[0088] A pattern function of the hybrid intelligent metasurface is constructed. Constraints of the hybrid intelligent metasurface are determined, and based on these constraints, a constraint model for the hybrid intelligent metasurface pattern is obtained. The constraints include, for example, the gain of the hybrid intelligent metasurface and the number of active elements in the hybrid intelligent metasurface. The constraint model is optimized using a convex optimization algorithm to obtain a reflection coefficient matrix for the hybrid intelligent metasurface, i.e., the layout strategy for the hybrid intelligent metasurface.

[0089] Furthermore, assuming that the hybrid intelligent metasurface is an M×N array, its directional pattern can be expressed by formula (1):

[0090]

[0091] Among them, E h (θ h ) is the radiation pattern of the feed horn antenna, k is the wave number, It is the mnth th The position vector of each cell, is the position vector of the feed horn antenna, is the observation direction, E unit (θ) is the mnth th The radiation pattern of each unit, It is the mnth th The phase of each unit, |Γ mn |mnth th For hybrid intelligent metasurface, its reflection coefficient can be divided into passive unit reflection coefficient |Γ passive | and active unit reflection coefficient |Γ active |.

[0092] Furthermore, the directional pattern of the hybrid smart metasurface can be expressed in matrix form:

[0093] E(θ)=a(θ) T Γ (2)

[0094] Among them, Γ and a(θ) T Expressed as:

[0095] Γ=[|Γ 11 |,...,|Γ MN |] T (3)

[0096]

[0097] Furthermore, g(Γ)=[g(|Γ 11 |),...,g(|Γ MN |)]T is the array strategy coefficient of the hybrid intelligent metasurface, the mnth th The coefficient of a unit can be expressed as:

[0098]

[0099] Furthermore, the constraint condition is set to obtain the maximum gain at the required scanning angle with the minimum number of active units. The optimization model can be written as:

[0100]

[0101] Among them, l, l1, l2 are the index numbers of the directional pattern, E( l ) indicates the first th Directional pattern. θ max is the maximum radiation direction, and α is the gain lower bound of the given hybrid smart metasurface.

[0102] Furthermore, let G(Γ (l) )=[g(Γ (1) ),...,g(Γ (L) )], formula (6) can be rewritten as:

[0103] min||G z→ ||0 (9)

[0104] Among them, G z→ Represents the zth th OK.

[0105] Furthermore, since the l0 norm is an NP-hard problem, the l1 / l2 mixed norm is used to approximate the l0 norm:

[0106]

[0107] Furthermore, since Equation (7) is a non-convex function, it can be rewritten as a convex function as Equation (12), and the optimization model can be expressed as:

[0108] min||G|| 1,2 (11)

[0109] stRe{|a (l) (θ max )Γ (l) |}≥α (l) (12)

[0110] Furthermore, the above optimization problem can be efficiently solved based on the convex optimization algorithm, and the optimal solution is the layout strategy of the hybrid intelligent metasurface.

[0111] like Figure 8As shown, an 8×16 hybrid intelligent metasurface array is constructed according to the design method of this embodiment. The dot indicates that the unit at this position in the array is set as an active unit, and the asterisk indicates that the unit at this position in the array is set as a passive unit.

[0112] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A hybrid intelligent metasurface, characterized in that: Including passive units and active units; The passive unit includes a metal radiation patch, a parasitic patch, a gap layer, a microstrip line layer, a foam layer, a metal floor, a first dielectric substrate and a second dielectric substrate; A metal radiation patch is provided on the upper surface of the first dielectric substrate, and a parasitic patch is provided on the lower surface thereof; A foam layer is provided between the first dielectric substrate and the second dielectric substrate; A slot layer is provided on the upper surface of the second dielectric substrate, and a microstrip line layer is provided on the lower surface thereof; The metal floor is arranged below the second dielectric substrate; The metal radiation patch, microstrip line layer and parasitic patch structures of the active unit and the passive unit are different, and the rest of the structures are the same.

2. The hybrid intelligent metasurface according to claim 1, characterized in that: The metal radiation patch of the passive unit is cross-shaped and is used to receive and radiate electromagnetic waves.

3. The hybrid intelligent metasurface according to claim 1, characterized in that The parasitic patch of the passive unit is specifically a square patch, and four trapezoidal patches are arranged around the square patch.

4. The hybrid intelligent metasurface according to any one of claims 1 to 3, characterized in that: The slot layer includes two orthogonally arranged "I"-shaped slots for energy coupling and row polarization conversion.

5. The hybrid intelligent metasurface according to any one of claims 1 to 3, characterized in that: The metal radiation patch of the active unit is a metal patch with a cross-shaped gap etched therein.

6. The hybrid intelligent metasurface according to claim 5, characterized in that: The parasitic patch of the active unit is specifically a square patch, and a square patch is respectively provided at the four corners of the square patch.

7. The hybrid intelligent metasurface according to claim 1, characterized in that: The microstrip line layer in the active unit and the passive unit includes a reflective phase shifter, and the reflective phase shifter includes a reconfigurable device. Changing the switching state of the reconfigurable device changes the reflection phase of the active unit and the passive unit. The microstrip line layer of the active unit includes a power amplifier for achieving signal amplification.

8. A hybrid intelligent metasurface array design method based on any one of claims 1 to 7, characterized in that: include: Constructing the directional pattern function of hybrid smart metasurface; Determining constraints of the hybrid smart metasurface; And based on the constraint conditions, a constraint model of the hybrid metasurface pattern is obtained; The constraint model is optimized based on a convex optimization algorithm to obtain the reflection coefficient matrix of the hybrid intelligent metasurface and determine the array form of the hybrid intelligent metasurface.

9. The hybrid intelligent metasurface array design method according to claim 8, characterized in that: The directional pattern function of the hybrid intelligent metasurface is specifically: Assuming that the hybrid smart metasurface array is an M×N array, its directional pattern is: Among them, E h (θ h ) is the radiation pattern of the feed horn antenna, k is the wave number, It is the mnth th The position vector of each cell, is the position vector of the feed horn antenna, is the observation direction, E unit (θ) is the mnth th The radiation pattern of each unit, It is the mnth th The phase of each unit, |Γ mn |mnth th The reflection coefficient of each unit is divided into the reflection coefficient of the passive unit |Γ for the hybrid intelligent metasurface. passive | and active unit reflection coefficient |Γ active |; Rewrite it into matrix form: E(θ) = a(θ) T Γ Among them, Γ and a(θ) T Expressed as: C=[|C 11 |,...,|C MN |] T 10. The hybrid intelligent metasurface array design method according to claim 9, characterized in that: The constraints include the gain of the hybrid intelligent metasurface and the number of active units. The optimized constraint model is: my||G|| 1,2 stRe{|E (l) (θ max )|}mRe{|a (l) (θ max )Γ (l) |}≥α (l) Among them, G(Γ (l) )=[g(Γ (1) ),...,g(Γ (L) )],g(Γ (l) ) represents the formation of the first th The array strategy coefficient when the directional pattern is (l) (θ max ) indicates the first th The gain when the directivity pattern is max Indicates the maximum scanning direction, α (l) is the given lth th The gain lower bound of the directional pattern.

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