A mechanically driven programmable sub-terahertz beam steering device and method

Abstract

The present invention discloses a mechanically driven, programmable sub-terahertz beam steering device and method. This device uses a mechanical structure with a controllable triangular wave element period and angle to control the generation of a target beam. An optimization model is constructed with the objective function maximizing the intensity of the target beam while suppressing the intensity of non-target beams. A mapping is established between the control parameters of the mechanical structure and the wave element incident angle and rotation angle. The sub-terahertz beam optimization model is iteratively solved to update the optimal angle and period, and the control parameters for implementing sub-terahertz beam steering are obtained based on the mapping relationship. This invention addresses the problem that sub-terahertz beam steering equipment cannot simultaneously meet the requirements of programmability, low cost, and low power consumption.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic wave beam control, and in particular to a mechanically driven programmable sub-terahertz beam control device and method. Background Art

[0002] Wireless data traffic has grown exponentially in recent decades. To meet the growing demand for higher data rates, future wireless communication systems are expected to move beyond the 5G new radio bands (0.41–7.125 GHz and 24.25–71 GHz) into the sub-terahertz range (90–300 GHz), unlocking significant new spectrum resources. However, due to their short wavelengths, sub-terahertz frequencies present challenges such as path loss and directivity. Consequently, sub-terahertz communication systems are susceptible to physical obstacles. Furthermore, the strong directivity of sub-terahertz signals results in extremely narrow beams, significantly limiting their usability in multi-user and mobile scenarios. Existing work has proposed several sub-terahertz beam steering methods, but their overall performance compromises programmability, low cost, and low power consumption, failing to meet practical requirements for sub-terahertz beam steering. Specifically, existing metasurfaces in the sub-terahertz band are broadly categorized as active and passive. Active metasurfaces integrate tunable and reconfigurable phase control technologies, such as phased arrays or liquid crystal materials, to achieve programmable beam steering. While this approach offers flexibility in adjusting the beam direction, it comes at the cost of high cost, high power consumption, and high complexity due to the need for complex RF chains, phase control hardware, and antenna arrays. In contrast, passive metasurfaces generate different phase distributions using passive elements such as metal resonators, dielectric resonators, or leaky waveguides. This approach offers a low-cost, compact alternative, but the beam direction is fixed by the physical structure and operating frequency, limiting dynamic programmability without hardware modifications. Summary of the Invention

[0003] The present invention aims to address the deficiencies of the prior art and to provide a mechanically driven programmable sub-terahertz beam steering device and method.

[0004] The object of the present invention is achieved through the following technical solutions: a programmable sub-terahertz beam steering device, the device comprising a metal surface, a scissor-type telescopic mechanical structure, and a spiral mechanical structure;

[0005] The metal surface is coupled to the support column through the metal plate to form a triangular wave-shaped unit structure; the vertical distance between two adjacent support columns is the wave unit period;

[0006] The scissor-type telescopic mechanical structure includes an upper part and a lower part, each of which is composed of several substructures. Each substructure includes two support arms cross-connected to each other through a central support point. The two ends of each support arm serve as end support points connected to the support arms of the remaining substructures. The upper and lower parts of the scissor-type telescopic mechanical structure are connected by support columns in the metal surface.

[0007] The screw mechanical structure is arranged at the bottom of the overall structure, and is coupled and fixed to the scissor-type telescopic mechanical structure through the connecting plates at both ends thereof. The lead screw is driven to rotate by controlling the pulse parameters of the motor, and the movement of the connecting plate at one end of the scissor-type telescopic mechanical structure is controlled to realize the contraction and expansion of the end points of the scissor-type telescopic mechanical structure.

[0008] Furthermore, the connection point between the scissor-type telescopic mechanical structure and the support column is the midpoint between the central support point and the end point.

[0009] Furthermore, the spiral mechanical structure is composed of a base, a motor, a fixed connecting plate, a movable connecting plate and a screw. The motor drives the screw to rotate by controlling the pulse parameters. The fixed connecting plate is connected to the base. The movable connecting plate is threadedly coupled to the screw and moves horizontally through the rotation of the screw. The scissors-type telescopic mechanical structure is respectively connected to the fixed connecting plate and the movable connecting plate, and the contraction and expansion of the end points of the scissors-type telescopic mechanical structure are controlled by the rotation of the screw.

[0010] Furthermore, the fixed connecting plate in the spiral mechanical structure includes a first fixed connecting plate and a second fixed connecting plate, which are respectively installed at both ends of the base, and one side of the scissor-type telescopic mechanical structure is fixed to the connecting plate at one end of the stepping motor.

[0011] On the other hand, this specification also provides a programmable sub-terahertz beam steering method using the device, the method comprising:

[0012] Construct a sub-THz beam optimization model with the objective function of maximizing the intensity of the target beam while suppressing the intensity of non-target beams;

[0013] Establish a mapping between the control parameters of the mechanical structure and the incident angle and rotation angle of the wave element;

[0014] The sub-terahertz beam optimization model is iteratively solved to update the optimal angle and period, and the control parameters for realizing sub-terahertz beam manipulation are obtained according to the mapping relationship.

[0015] Furthermore, the sub-terahertz beam optimization model is specifically as follows:

[0016] The target beam intensity and non-target beam intensity are calculated using a power pattern function, and the difference between the non-target beam intensity and the target beam intensity is used as the objective function. The vector of the non-target beam is represented as a direction within the range of 0° to 180°, excluding other angles corresponding to the target direction.

[0017] Furthermore, the power mode function is implemented by a wave element cycle and the angle of incidence Control, the power mode function of the target beam specifically includes:

[0018] in, is the incident wavelength, is the number of wave elements, Represents the elements in the target beam vector.

[0019] Furthermore, the mapping of the control parameters of the mechanical structure to the incident angle and the rotation angle of the wave element includes: indirectly controlling the incident angle by rotating the mechanical structure, thereby causing a relative deflection between the incident angle and the target beam direction, when rotating counterclockwise by an angle When the incident angle changes from becomes , the target beam angle is from becomes .

[0020] Furthermore, the sub-terahertz beam optimization model is updated through iterative solution of the optimal angle and period as follows:

[0021] The sub-terahertz beam optimization model is decomposed into a quadratic programming problem. The parameter gradient and Hessian matrix are used to determine the optimization direction. The optimized rotation angle and wave element period are updated by iteratively solving the quadratic programming problem.

[0022] Beneficial effects of the present invention:

[0023] The present invention provides a low-cost and low-power sub-terahertz metasurface design, which can achieve sub-terahertz beamforming by folding ultra-thin metal materials, and realize high-precision and flexible beam control by using a scissor-type mechanical structure driven by a lead screw.

[0024] Based on the grating diffraction effect, this paper proposes a method for diffracting incident sub-terahertz signals using a low-cost passive triangular wave structure to generate a directional beam. By integrating a programmable mechanical control structure with zero static power consumption, this method enables dynamic adjustment of the triangular wave structure parameters, thereby achieving programmable control of the output beam direction. This method offers advantages such as a simple structure, low cost, extremely low energy consumption, and flexible beam control, making it suitable for reconfigurable beam steering components in next-generation sub-terahertz communication and imaging systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The figure is a schematic diagram of the overall structure of the programmable sub-terahertz beam steering mechanical structure;

[0026] Figure 2 Schematic diagram of the triangular wave structure of the programmable sub-terahertz beam steering mechanism;

[0027] Figure 3 Schematic diagram of the scissor-type telescopic structure of the programmable sub-terahertz beam steering mechanical structure;

[0028] Figure 4 A schematic diagram of the lead screw control structure of a programmable sub-terahertz beam steering mechanical structure;

[0029] Figure 5 It is a schematic diagram of the mapping between the incident angle of the wave element and the rotation angle;

[0030] Figure 6 Schematic diagram for optimizing the scene;

[0031] Figure 7 Schematic diagram of the optimization iterative process;

[0032] Figure 8 Schematic diagram of beamforming.

[0033] Among them, 101 represents a scissor-type telescopic mechanical structure, 102 represents a spiral mechanical structure, 103 represents a bracket, 104 represents a metal surface, 201 represents a metal plate, 202 represents a support column, 302 represents a support arm, 303 represents a substructure, 304 represents a support point, 305 represents a connection point, 401 represents a first connecting plate, 402 represents a stepping motor, and 403 represents a screw rod. DETAILED DESCRIPTION

[0034] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0035] This method primarily consists of a programmable sub-terahertz beam steering mechanical structure and a control parameter optimization algorithm. The method uses triangular wave elements as the wave structure. When an external parallel electromagnetic wave is incident on the wave structure, the uneven surface causes the signal to scatter in different directions. According to Bragg's law, the scattered signal is diffracted to form spherical waves, which radiate outward through the aperture. The spherical waves propagate divergently in different directions, and when they constructively interfere with other spherical waves at specific angles, a focused beam is formed. This method achieves programmable beam steering by controlling the parameters of the wave structure through a programmable mechanical structure. Furthermore, by constructing a mapping relationship between beam direction and wave element parameters, the method establishes an efficient beam architecture, thereby optimizing the target beam solution process and ultimately achieving precise beam steering.

[0036] Specifically, an embodiment of the present invention provides a mechanically driven programmable sub-terahertz beam steering device and method, including:

[0037] The overall structure of the programmable sub-terahertz beam steering mechanical structure is mainly composed of a metal surface, a scissor-type telescopic mechanical structure 101 and a screw mechanical structure 102, such as Figure 1 As shown: Metal surface 104 is horizontally mounted on the scissor-type telescopic mechanical structure 101, forming a triangular waveform unit structure with this structure. The screw mechanical structure 102 is set at the bottom of the overall structure and is coupled and fixed to the scissor-type telescopic mechanical structure 101 through connecting plates at both ends of its bracket 103, forming an integrated mechanical system. The specific design details of each structure are described below:

[0038] (1) Metal surface. Figure 2 As shown, the metal surface includes a metal plate 201 and a support column 202. The metal plate 201 is coupled to the support column 202 to form a triangular wave unit structure (referred to as a triangular wave element). Each support column is connected to the bottom vertex of the triangle. Two adjacent support columns constitute a triangular wave element. The vertical distance between the two adjacent support columns defines the wave element period. The length of the triangular wave element must meet the adjustable range of the wave element period of 2 mm to 6 mm, and the wave element width is 5 cm. There are two main reasons why the present invention chooses triangular wave elements. First, the triangular wave element provides excellent mechanical control, allowing the wave element period to be adjusted by changing the relative position of the bottom vertex. Second, the beam generated by the triangular wave element has a strong beam intensity.

[0039] (2) Scissor-type telescopic mechanical structure. Figure 3 As shown, the scissor-type telescopic mechanical structure 101 is composed of a series of support arms 302 connected to each other at support points 304. Two adjacent support arms 302 are connected to form a substructure 303. By manipulating the distance between the connecting plates of the scissor-type telescopic mechanical structure, displacement is effectively transmitted to each substructure 303, and a constant distance is maintained between adjacent joint points C. This displacement transmission characteristic enables precise periodic control of the wave element. In the setting of the connection point 305, the present invention connects the support column coupled to the wave element to the support point ( Figure 3 Point A in the figure) and the joint point ( Figure 3 The midpoint between point C in Figure 3 The waveform period can be precisely controlled, thereby significantly improving the operating accuracy of the system.

[0040] (3) Spiral mechanical structure. The present invention uses a spiral mechanical structure to manipulate the distance between the end points of the scissor-type telescopic mechanical structure, such as Figure 4As shown, the spiral mechanism consists of a stepper motor 402, a lead screw 403, and connecting plates. The connecting plates include a first connecting plate 401, a second connecting plate, and a third connecting plate. The stepper motor 402 and the lead screw 403 are connected together via a rotating shaft and are placed at the bottom of the spiral mechanism. The three connecting plates are placed at both ends and in the middle of the lead screw 403 structure. The first connecting plate 401 and the third connecting plate at both ends are fixed to the base, while the second connecting plate in the middle is threadedly coupled to the lead screw 403. The base has a rotating thread. One side of the scissor-type telescopic mechanism is fixed to the first connecting plate 401 at one end of the stepper motor 402, and the other end is fixed to the second connecting plate in the middle. The stepper motor 402 is connected to the lead screw 403 via a rotating shaft and is placed at the bottom of the spiral mechanism. The three connecting plates are placed at both ends and in the middle of the lead screw 403 structure. The connecting plates at both ends are fixed to the base, while the connecting plate in the middle is coupled to the thread structure of the lead screw 403. The base is provided with a rotating thread structure. One end of the scissor-like telescopic mechanism is fixedly connected to the first connecting plate 401 at the end near the stepper motor 402, and the other end is fixedly connected to the second connecting plate in the middle, thereby achieving controllable extension and retraction of the entire structure. The motor controls the rotation angle based on the number of pulses corresponding to the control parameter, thereby driving the lead screw to rotate, thereby causing the end points of the scissor-like telescopic mechanism to contract and expand. To achieve precise beam control, the present invention utilizes a two-phase, four-wire NEMA8 stepper motor 402 to precisely control the rotation angle of the mechanical surface and the period of the wave element.

[0041] Based on the aforementioned mechanically driven programmable sub-terahertz beam steering device, embodiments of the present invention also provide a mechanically driven programmable sub-terahertz beam steering method, proposing a parameter optimization framework to solve the optimal control parameters for the desired beam direction. The main steps are as follows:

[0042] (1) Constructing an optimization model. The present invention adjusts the control parameters to maximize the intensity of the target beam while suppressing the intensity of the non-target beam. In general, the frequency of the incident signal is fixed, which means that the wavelength remains unchanged. Therefore, the present invention optimizes the wavelet period ( ) and the angle of incidence ( ) to achieve target beam steering. Optimize the objective function Expressed as

[0043]

[0044] in, is the angle of incidence, is the period of each wave element, is the vector of the target beam. represents the target beam vector ( ), and Represents the elements in the non-target beam vector, which are expressed as directions in the range 0° to 180°, excluding the target direction Other corresponding angles. and The weight coefficient needs to be set according to the number of target beams and is generally set to 1. is the power mode function and is defined as follows:

[0045]

[0046] in, is the incident wavelength, is the number of triangle wave elements.

[0047] (2) Mapping of the incident angle of the wave element and the rotation angle. In actual control, the present invention controls the incident angle by rotating the screw thread at the bottom of the spiral mechanical structure, thereby causing the relative deflection between the incident angle and the target beam direction. Specifically, Figure 5 As shown, when rotating counterclockwise by an angle When the incident angle becomes , the target beam angle becomes Therefore, the mapping of control parameters can be achieved through this relationship.

[0048] (3) Objective function construction. Based on the above analysis, the objective function constructed by the present invention is:

[0049]

[0050]

[0051]

[0052] in and The minimum adjustable period and the maximum adjustable period are set to 2 mm and 6 mm respectively.

[0053] (4) Optimize the parameters. Due to the existence of nonlinear form , which is a nonlinear optimization problem. To solve this problem, the present invention proposes a parameter optimization algorithm. The present invention decomposes the entire nonlinear optimization problem into a quadratic programming problem and updates the optimization variables by iteratively solving the quadratic programming problem. The solution steps are as follows:

[0054] Step S100: Input target beam angle and the angle of incidence ;

[0055] Step S110: Construct the parameter variable vector to be optimized = [ , ],in Indicates the rotation angle, Indicates the wave element period;

[0056] Step S120: Randomly initialize parameter variables ;

[0057] Step S130: Determine whether the model has converged. If the objective function is less than a threshold, the model has converged. If not, perform the following steps:

[0058] Step S131: Calculate current variables The gradient vector under ,Right now:

[0059] ;

[0060] Step S132: Calculate the Hessian matrix H of the current variable, that is:

[0061] ;

[0062] Step S133: Based on the current gradient and Hessian matrix, solve the optimal step size , the goal is to minimize the following expression: ;

[0063] Step S134: Update parameter variables: ;

[0064] Step S135: Return to step S130;

[0065] Step S140: When the model converges, output the optimal rotation angle , and the wavelet period .

[0066] In order to avoid falling into local optimum, the present invention randomly initializes the optimization variables and performs multiple optimization runs to determine the final optimal parameters.

[0067] (5) Results presentation. This invention uses an example to illustrate the entire optimization process. Figure 6 As shown, two sub-terahertz nodes need to establish communication links with sub-terahertz access points. The sub-terahertz access points are located at 130° directions, and the two sub-terahertz nodes are located at 70° and 140° directions, respectively. Figure 7 The process of solving the optimal control parameters through the parameter optimization framework is shown. After 10 iterations, the system meets the convergence criteria, the optimal rotation angle is 9°, and the optimal period is 1.8 mm. The target beam direction solved by the optimized parameters is shown in Figure 8Through the parameter optimization framework, the optimal control parameters can be quickly solved according to the beam requirements.

[0068] The above embodiments are used to illustrate the present invention rather than to limit the present invention. Any modifications and changes made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A programmable sub-terahertz beam steering device, characterized in that: The device consists of a metal surface, a scissor-type telescopic mechanical structure and a spiral mechanical structure; The metal surface is coupled to the support column through the metal plate to form a triangular wave-shaped unit structure; the vertical distance between two adjacent support columns is the wave unit period; The scissor-type telescopic mechanical structure includes an upper part and a lower part, each of which is composed of several substructures. Each substructure includes two support arms cross-connected to each other through a central support point. The two ends of each support arm serve as end support points connected to the support arms of the remaining substructures. The upper and lower parts of the scissor-type telescopic mechanical structure are connected by support columns in the metal surface. The spiral mechanical structure is arranged at the bottom of the overall structure and is coupled and fixed to the scissor-type telescopic mechanical structure through the connecting plates at both ends. The pulse parameters of the motor are controlled to drive the screw to rotate, and the movement of the connecting plate at one end of the scissor-type telescopic mechanical structure is controlled to realize the contraction and expansion of the end points of the scissor-type telescopic mechanical structure.

2. A programmable sub-terahertz beam steering device according to claim 1, characterized in that: The connection point between the scissor-type telescopic mechanical structure and the support column is the midpoint between the central support point and the end point.

3. The programmable sub-terahertz beam steering device according to claim 1, characterized in that: The spiral mechanical structure consists of a base, a motor, a fixed connecting plate, a movable connecting plate and a lead screw. The motor drives the lead screw to rotate by controlling the pulse parameters. The fixed connecting plate is connected to the base. The movable connecting plate is threadedly coupled to the lead screw and moves horizontally through the rotation of the lead screw. The scissor-type telescopic mechanical structure is respectively connected to the fixed connecting plate and the movable connecting plate, and the contraction and expansion of the end points of the scissor-type telescopic mechanical structure are controlled by the rotation of the lead screw.

4. The programmable sub-terahertz beam steering device according to claim 3, characterized in that: The fixed connecting plates in the spiral mechanical structure include a first fixed connecting plate and a second fixed connecting plate, which are respectively installed at two ends of the base. One side of the scissor-type telescopic mechanical structure is fixed to the connecting plate at one end of the stepping motor.

5. A programmable sub-terahertz beam steering method using the device according to any one of claims 1 to 4, characterized in that: The method includes: Construct a sub-THz beam optimization model with the objective function of maximizing the intensity of the target beam while suppressing the intensity of non-target beams; Establish a mapping between the control parameters of the mechanical structure and the incident angle and rotation angle of the wave element; The sub-terahertz beam optimization model is iteratively solved to update the optimal angle and period, and the control parameters for realizing sub-terahertz beam manipulation are obtained according to the mapping relationship.

6. The programmable sub-terahertz beam steering method according to claim 5, characterized in that: The sub-terahertz beam optimization model is specifically as follows: The target beam intensity and non-target beam intensity are calculated using a power pattern function, and the difference between the non-target beam intensity and the target beam intensity is used as the objective function. The vector of the non-target beam is represented as a direction within the range of 0° to 180°, excluding other angles corresponding to the target direction.

7. The programmable sub-terahertz beam steering method according to claim 6, characterized in that: The power mode function is cycled by the wave element and the angle of incidence Control, the power mode function of the target beam specifically includes: ; in, is the incident wavelength, is the number of wave elements, Represents an element in the target beam vector.

8. The programmable sub-terahertz beam steering method according to claim 5, wherein: The mapping between the control parameters of the mechanical structure and the incident angle and the rotation angle of the wave element is established by indirectly controlling the incident angle by rotating the mechanical structure, thereby causing a relative deflection between the incident angle and the target beam direction. When the incident angle changes from becomes , the target beam angle is from becomes .

9. The programmable sub-terahertz beam steering method according to claim 5, characterized in that: The sub-terahertz beam optimization model is iteratively solved to update the optimal angle and period as follows: The sub-terahertz beam optimization model is decomposed into a quadratic programming problem. The parameter gradient and Hessian matrix are used to determine the optimization direction. The optimized rotation angle and wave element period are updated by iteratively solving the quadratic programming problem.

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