A beam switching method for millimeter-wave terahertz liquid crystal phased array

Abstract

This invention provides a beam switching method for a millimeter-wave terahertz liquid crystal phased array, relating to the field of phased array technology. The method involves configuring the liquid crystal phased array to obtain the number of liquid crystal antennas, array type, and element spacing; configuring the transmit signal and line-of-sight transmission channels to obtain the transmit signal; precoding and decoupling the transmit signal; setting the phase shifter phase based on the analog precoding matrix to obtain the phase shifter phase setting result; constraining the analog precoding matrix in the transmit signal to obtain the bit constraint result; based on the bit constraint result, performing quantization angle reset and bit joint constraint on the analog precoding matrix to obtain the reset phase shifter angle; and analyzing the beam switching gain based on the reset phase shifter angle to obtain the beam switching result, thus completing the beam switching of the millimeter-wave terahertz liquid crystal phased array. This invention solves the problem of how to shorten the beam switching time of a liquid crystal phased array.

Description

Technical Field

[0001] This specification relates to the field of phased array technology, and in particular to a beam switching method for a millimeter-wave terahertz liquid crystal phased array. Background Technology

[0002] With increasingly scarce spectrum resources and rising communication service speeds, new spectrum, especially millimeter-wave (30GHz~300GHz) and terahertz (0.1THz~10THz) spectrums supporting broadband performance, has become an important research and development direction. However, millimeter-wave and terahertz frequencies suffer from high path loss and short transmission distances, forcing phased arrays to become the core technology for the practical application of millimeter-wave and terahertz technologies. Traditional mechanically scanned antennas are large and heavy, posing difficulties for vehicle-mounted, airborne, and human-carrying applications. Liquid crystals, as materials with tunable dielectric constants, have gradually become an ideal choice for solving this problem due to their low frequency loss and low cost. Liquid crystal-based phased array antenna technology has become a research hotspot in recent years. However, a significant problem with liquid crystal phased arrays is their relatively slow beam switching speed, mainly due to the slow switching time between states in liquid chromatography devices, with reconfiguration times reaching the second level. For some applications that require high-speed beam scanning or rapid dynamic adjustment (such as real-time monitoring, communication beam tracking, etc.), the beam switching speed of millimeter-wave terahertz liquid crystal phased arrays has become a bottleneck restricting their widespread application. How to shorten the beam switching time of liquid crystal phased arrays has become an urgent problem to be solved.

[0003] Currently, research on improving the response speed of liquid crystal phase shifters mainly focuses on the following directions: first, accelerating the response by using polymerizable liquid crystal compounds; second, employing dual-frequency liquid crystal materials to achieve faster adjustment at different frequencies; and third, optimizing the response time by utilizing material properties to reduce the thickness of the liquid crystal cavity. These research directions all aim to improve the control efficiency and dynamic performance of liquid crystal phase shifters to meet the demands for higher speeds and more precise control. However, these methods often face problems such as increased material costs, increased complexity, and excessive power consumption. Summary of the Invention

[0004] To address the aforementioned shortcomings in the prior art, this invention provides a beam switching method for millimeter-wave terahertz liquid crystal phased arrays, which solves the problem of how to shorten the beam switching time of liquid crystal phased arrays.

[0005] To achieve the aforementioned objectives, the present invention employs the following technical solution: a beam switching method for a millimeter-wave terahertz liquid crystal phased array, comprising:

[0006] S1: By setting the liquid crystal phased array, the number of liquid crystal antennas, array type, and element spacing are obtained;

[0007] S2: Based on the number of liquid crystal antennas, the array type, and the array element spacing, the transmission signal is obtained by setting the transmission signal and the line-of-sight transmission channel;

[0008] S3: Perform precoding decoupling on the transmitted signal, set the phase shifter phase based on the analog precoding matrix, and obtain the phase shifter phase setting result;

[0009] S4: Perform bit constraint on the analog precoding matrix in the transmitted signal to obtain the bit constraint result;

[0010] S5: Based on the bit constraint results, the quantization angle is reset and the bit is jointly constrained on the analog precoding matrix to obtain the reset phase shifter angle;

[0011] S6: Based on the reset phase shifter angle, analyze the gain result of beam switching to obtain the beam switching result and complete the beam switching of the millimeter-wave terahertz liquid crystal phased array.

[0012] Furthermore, the expression for the line-of-sight transmission channel is:

[0013] ;

[0014] ;

[0015] ;

[0016] ;

[0017] in, Indicates the line-of-sight transmission channel. Represents the normalization factor. Indicates the receiver steering vector. Indicates the target angle at the receiving end. This represents the turning vector of the transmitting end. Indicates the target angle at the launching end. This indicates the conjugate transpose. Indicates the number of transmitting antennas. Indicates the number of antennas at the receiving end. This represents the transpose of the receiver's steering vector. This represents the transpose of the steering vector at the transmitting end, where j represents the complex unit. d represents the wavelength of the transmitted wave, and d represents the spacing between array elements.

[0018] Furthermore, the expression for the transmitted signal is:

[0019] ;

[0020] ;

[0021] in, Indicates the transmission of signals. Represents the decoding matrix. Indicates the line-of-sight transmission channel. Represents the analog precoding matrix. Indicates the transmission of a signal. Denotes the first orthogonal matrix. This represents a diagonal matrix whose elements on the main diagonal are singular values. Describes the second orthogonal matrix. This indicates the conjugate transpose.

[0022] Furthermore, the expression for the simulated precoding matrix is:

[0023] ;

[0024] in, This represents the transpose of the analog precoding matrix, where j represents the complex unit. d represents the wavelength of the transmitted wave, and d represents the spacing between array elements. Indicates the number of transmitting antennas. This indicates the target angle at the launch end.

[0025] Furthermore, the bit constraint result includes quantization angle constraint, carry probability, and truncation probability, wherein the expression for the bit constraint result is:

[0026] ;

[0027] ;

[0028] in, This indicates a constraint from a quantitative perspective. and Both represent adjacent quantization angles. Indicates the ideal angle. Indicates the interval between quantization angles. This represents the carry probability. This represents the probability of discarding the tail. This indicates the second quantization error. This represents the first quantization error.

[0029] Further, S5 includes:

[0030] Based on the bit constraint results and phase shift range, the quantization angle of the analog precoding matrix is ​​reset to obtain the reset quantization angle;

[0031] The phase shifter angle is reset using the reset quantization angle and the bit joint constraint to obtain the reset phase shifter angle.

[0032] Furthermore, the expression for the gain result is:

[0033]

[0034] ;

[0035] in, This indicates the gain of the antenna array at various angles. This indicates the target angle at the receiving end, and P represents the power of the omnidirectional radiating liquid crystal antenna. Represents the analog precoding matrix. This indicates the conjugate transpose. This indicates transpose, j represents the complex unit, and d represents the spacing between antenna elements. Indicates the number of transmitting antennas. The wavelength of the emitted wave is represented by k, and the wave number is represented by k. This indicates the target angle at the launch end.

[0036] The beneficial effects of this invention are as follows: This invention provides a beam switching method for millimeter-wave terahertz liquid crystal phased arrays. It optimizes the beam switching process and improves the beam switching speed by combining bit constraints and reducing the phase shift range of the liquid crystal phase shifter. A two-bit phase shifter is used, and its phase shift angle is constrained to balance the phase shifter adjustment speed with system cost, while ensuring beamforming accuracy and main lobe gain. In this way, the startup speed and beam switching speed of the liquid crystal phased array can be greatly improved. Attached Figure Description

[0037] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0038] Figure 1 This is an exemplary flowchart of a beam switching method for a millimeter-wave terahertz liquid crystal phased array according to some embodiments of this specification;

[0039] Figure 2 This is an exemplary schematic diagram showing the comparison of liquid crystal phase shift delay between 180-degree and 270-degree phase shift ranges according to some embodiments of this specification;

[0040] Figure 3 This is an exemplary schematic diagram showing the direction comparison of the array antenna beam switching process of a liquid crystal phased array system without phase shift range constraints and bit shift phase range joint constraints according to some embodiments of this specification;

[0041] Figure 4 This is an exemplary schematic diagram comparing the direction of the phase-shifting process of the liquid crystal phased array system according to some embodiments of this specification, where the joint constraint of bit and phase-shift range is performed versus the constraint of phase-shift range array antenna beam switching using only bit constraints. Detailed Implementation

[0042] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0043] Example

[0044] Figure 1 This is an exemplary flowchart illustrating a beam switching method for a millimeter-wave terahertz liquid crystal phased array according to some embodiments of this specification. Figure 1 As shown, the process includes the following steps. In some embodiments, the process may be executed by a processor.

[0045] S1: By setting the liquid crystal phased array, the number of liquid crystal antennas, array type, and element spacing are obtained.

[0046] Liquid crystal phased arrays are phased array antennas based on liquid crystals, capable of supporting wideband performance in millimeter-wave and terahertz frequencies. For example, a liquid crystal phased array can include a transmitter liquid crystal phased array and a receiver liquid crystal phased array containing multiple liquid crystal phase shifters in a uniform linear array. The transmitter end of the antenna array consists of... It consists of several antennas, and the receiver is composed of... It consists of several antennas, with equal spacing between the elements at the transmitting and receiving ends. ,in Indicates the wavelength of the emitted wave , Represents the speed of light. The frequency of the transmitted wave is indicated; the operating parameters of the liquid crystal phased array are shown in Table 1.

[0047] Table 1 Operating Parameters of Liquid Crystal Phased Array

[0048]

[0049] A liquid crystal phase shifter is a device used to adjust the phase of an antenna.

[0050] In some embodiments, the processor can perform beamforming on the array antenna by setting the phase of the liquid crystal phase shifter.

[0051] In some embodiments, the processor can utilize liquid crystal phase shifters to perform phase modulation on the liquid crystal phased array to achieve analog precoding and obtain beamforming. Specifically, the processor can achieve analog precoding by adjusting the phase of each liquid crystal phase shifter: analog precoding is achieved by the phase of the liquid crystal phase shifter, and each value in the analog precoding matrix corresponds to the value that each liquid crystal phase shifter needs to shift. Analog precoding and beamforming of the transmitted signal are achieved by adjusting the phase of the phase shifters.

[0052] S2: Based on the number of liquid crystal antennas, the array type, and the array element spacing, a transmission signal is obtained by setting the transmission signal and the line-of-sight transmission channel.

[0053] The transmitted signal is the signal from the transmitting end of the liquid crystal phased array antenna. For example, the transmitted signal can be represented as... ,in, This represents the analog precoding matrix, with a size of [value missing]. , This represents the transmitted signal from the transmitting antenna, with a magnitude of .

[0054] In some embodiments, simulated beamforming involves all antenna elements sharing a single radio frequency chain. .

[0055] A line-of-sight (LOS) transmission channel is a channel used to transmit transmitted signals. For example, the channel can be a Loss-of-Sight (LoS) channel that does not consider multipath delay and channel fading.

[0056] In some embodiments, the expression for the line-of-sight transmission channel can be:

[0057] ;

[0058] ;

[0059] ;

[0060] ;

[0061] in, Indicates the line-of-sight transmission channel. Represents the normalization factor. Indicates the receiver steering vector. Indicates the target angle at the receiving end. This represents the turning vector of the transmitting end. Indicates the target angle at the launching end. This indicates the conjugate transpose. Indicates the number of transmitting antennas. Indicates the number of antennas at the receiving end. This represents the transpose of the receiver's steering vector. This represents the transpose of the steering vector at the transmitting end, where j represents the complex unit. d represents the wavelength of the transmitted wave, and d represents the spacing between array elements.

[0062] A transmitted signal is a signal that is transmitted from the transmitted signal to the target location through a channel.

[0063] In some embodiments, the expression for the transmitted signal can be:

[0064] ;

[0065] ;

[0066] in, Indicates the transmission of signals. Represents the decoding matrix. Indicates the line-of-sight transmission channel. Represents the analog precoding matrix. Indicates the transmission of a signal. Denotes the first orthogonal matrix. This represents a diagonal matrix whose elements on the main diagonal are singular values. Describes the second orthogonal matrix. This indicates the conjugate transpose.

[0067] In some embodiments, the transmitted signal can be size, Indicates the number of data streams. Size can be , Size can be , Size can be , Size can be , Size can be .

[0068] In some embodiments, the processor can obtain information from the analog precoding matrix F from matrix V, that is: , ,in, Indicates size is submatrix, Indicates size is The submatrix.

[0069] S3: Perform precoding decoupling on the transmitted signal, set the phase shifter phase based on the analog precoding matrix, and obtain the phase shifter phase setting result.

[0070] The analog precoding matrix is ​​a matrix used for setting the phase of the phase shifter.

[0071] In some embodiments, the expression for the simulated precoding matrix can be:

[0072] ;

[0073] in, This represents the transpose of the analog precoding matrix, where j represents the complex unit. d represents the wavelength of the transmitted wave, and d represents the spacing between array elements. Indicates the number of transmitting antennas. Indicates the target angle at the launching end. This indicates the amplitude of each liquid crystal antenna. This indicates the phase of each liquid crystal antenna.

[0074] The phase of the phase shifter is the phase of each liquid crystal antenna after being adjusted by the phase shifter.

[0075] In some embodiments, the processor can use an analog precoding matrix to set the phase of the precoded decoupled transmission signal, wherein the phase corresponding to each element is the phase that each liquid crystal phase shifter needs to shift, thus obtaining the phase shifter phase; wherein, the analog precoding matrix is ​​obtained by setting the initial phase of the first array element to 0 and then normalizing the power of the precoding matrix.

[0076] S4: Perform bit constraint on the analog precoding matrix in the transmitted signal to obtain the bit constraint result.

[0077] Bit constraint results are constraints used to optimize the analog precoding matrix. For example, bit constraint results may include quantization angle constraints, carry probabilities, and tail-drop probabilities.

[0078] In some embodiments, the processor may use rounding to constrain the bit position of the analog precoding matrix in the transmitted signal, with each quantization angle set at equal intervals, the interval between the quantization angles being [missing information]. , m represents the number of bits selected, for any ideal angle in the analog precoding matrix F. Both have two adjacent quantization angles. and ,make ,get The results of the quantitative constraints.

[0079] In some embodiments, when the processor can directly perform quantization using rounding, the quantization error can be minimized, and the maximum quantization error generated in this case is... Choosing 0° as the first quantization angle, the various quantization angles at this time are: .

[0080] In some embodiments, the processor can utilize a phase quantization method with random phase feeding. By appropriately allocating the number of carry and truncation operations, the total carry phase quantity is made numerically equal to the total truncation phase quantity, thereby reducing the overall phase feeding error of the phased array antenna. When using the phase quantization method with random phase feeding, the probabilities of carry and truncation are p and q, respectively. When quantizing the phase in the analog precoding matrix, the phase is quantized with carry and truncation according to the probabilities p and q of the two possible values ​​method.

[0081] In some embodiments, the expression for the bit constraint result is:

[0082] ;

[0083] ;

[0084] in, This indicates a constraint from a quantitative perspective. and Both represent adjacent quantization angles. Indicates the ideal angle. Indicates the interval between quantization angles. This represents the carry probability. This represents the probability of discarding the tail. This indicates the second quantization error. This represents the first quantization error.

[0085] S5: Based on the bit constraint results, the analog precoding matrix is ​​subjected to quantization angle reset and bit joint constraint to obtain the reset phase shifter angle.

[0086] Resetting the phase shifter angle is the phase shifter range angle that reduces response time.

[0087] In some embodiments, the processor can reset the quantization angle of the analog precoding matrix based on the bit constraint result and the phase shift range to obtain a reset quantization angle; and reset the phase shifter angle using the reset quantization angle and the bit joint constraint to obtain a reset phase shifter angle.

[0088] Resetting the quantization perspective is a quantization perspective that reduces response time.

[0089] In some embodiments, the processor can shift the phase range of the phase shifter from Constrained to Then at this time There cannot be quantification angles between the ranges; all quantification angles can only exist within... Within this range, based on the rounding method for setting the quantization angle, the quantization angle is reset at equal intervals. Within the range; constrain the phase shift range to Then, 0° is used as the first quantization phase, with This is the final quantization phase. Following rounding, the quantization angle interval at this point... ,in This represents the number of quantization bits. The various quantization angles at this point are respectively... .

[0090] In some embodiments, the processor can utilize the two possible value method to process the analog precoding matrix from a new quantization perspective. Quantization is performed on the analog precoding matrix. Mid-phase Quantization is performed directly using the two possible values ​​method. One of these quantization perspectives; for precoding matrices Mid-phase exist When quantizing the phase between them, the carry quantization angle is... That is, 0°, the angle of the rounding quantization is At this point, the carry quantization error... Rounding quantization error Finally, the two possible values ​​method is used to... Perform carry-over or rounding quantization.

[0091] S6: Based on the reset phase shifter angle, analyze the gain result of beam switching to obtain the beam switching result and complete the beam switching of the millimeter-wave terahertz liquid crystal phased array.

[0092] Gain results reflect the degree to which beam switching time is reduced.

[0093] Gain loss reflects the magnitude of quantization error caused by resetting the phase shifter angle. For example, gain loss can be characterized by the radiation pattern of an array antenna.

[0094] In some embodiments, constraining the phase shift range will cause an increase in quantization error, which will lead to a decrease in beamforming main lobe gain. The main lobe gain loss is analyzed to obtain the gain loss; the specific comparison of gain loss is shown in Table 2.

[0095] Table 2 Gain Loss Comparison Table

[0096]

[0097] Table 2 compares the main lobe gain of the simulated liquid crystal phased array system at various targets under different conditions: without phase shift range constraints, with combined bit-shift phase range constraints, and with 1-bit phase shift range constraints. The comparison shows the gain under different conditions: without phase shift range constraints, with combined bit-shift phase range constraints, and when the phase shift range is constrained to 180 degrees. The four quantitative perspectives are respectively , , and At this time and this The maximum quantization error of the angle within the range is Compared to unconstrained phase shift range, the range was reduced by 33%. this The maximum quantization error of the angle within the range is Compared to the unconstrained phase shift range, the range has been improved by 100%, because at this time... The error increase within this range is too large, and the reduction in errors at other angles cannot compensate for the impact of this error increase. Table 2 shows that compared to the scheme using only 2-bit constraints without constraining the maximum phase shift range, the proposed scheme with 2-bit constraints and a phase shift range constrained to 180 degrees shows gain loss at all target angles except 0 degrees, but the maximum loss is only about 1dB, which is within an acceptable range. Further comparing the combined bit-shift and phase shift range constraints with using 1-bit constraints, Table 2 shows that while the latter guarantees a 180-degree phase shift range, its gain shows a significant loss compared to the combined bit-shift and phase shift range constraints.

[0098] In some embodiments, the expression for the gain result can be:

[0099]

[0100] ;

[0101] in, This indicates the gain of the antenna array at various angles. This indicates the target angle at the receiving end, and P represents the power of the omnidirectional radiating liquid crystal antenna. Represents the analog precoding matrix. This indicates the conjugate transpose. This indicates transpose, j represents the complex unit, and d represents the spacing between antenna elements. Indicates the number of transmitting antennas. The wavelength of the emitted wave is represented by k, and the wave number is represented by k. This indicates the target angle at the launch end.

[0102] The beam switching result reflects the beam switching response time of the liquid crystal phased array.

[0103] In some embodiments, the processor can obtain beam switching results by constraining the bit positions and phase shift range of the liquid crystal phase shifter based on the proportional relationship between the phase shift angle and the response time of the liquid crystal phase shifter; for example, the comparison of beam switching results is shown in Table 3.

[0104] Table 3 Comparison of Beam Switching Results

[0105]

[0106] Table 3 shows the response time for different maximum phase shift ranges. By constraining the phase shift angle to 0° to 180°, the phase shift range can be reduced by 90° compared to the 0° to 270° range using only a 2-bit constraint. Based on a review of relevant literature and time estimations, this constraint can significantly reduce the turn-on time of the phase shifter. ) and closing time ( This shortens the overall response time. As shown in Table 3, when the phase shift angle is 180°, Ton and Toff are 3 seconds and 7 seconds respectively, while when the phase shift angle increases to 270°, Ton and Toff increase to 5 seconds and 10 seconds respectively. This indicates that by limiting the phase shift angle to 0° to 180°, Ton can be reduced by 40% and Toff by 30%.

[0107] Figure 2 This is an exemplary schematic diagram showing a comparison of liquid crystal phase shift delay between 180-degree and 270-degree phase shift ranges according to some embodiments of this specification, such as... Figure 2 As shown, liquid crystal response time relatively The phase shift range is relatively long; limiting it from 270 degrees to 180 degrees can... shorten by 40%, Shortened by 30%.

[0108] Figure 3 This is an exemplary schematic diagram illustrating the direction comparison of the array antenna beam switching process in a liquid crystal phased array system without phase shift range constraints and bit shift range joint constraints, according to some embodiments of this specification. Figure 3 As shown, due to the characteristics of liquid crystals, beam switching requires resetting from the current state to the initial state before switching to the next state. The beam switching time required in this process is... Combining Table 3 with Figure 3It can be seen that when switching from the initial target angle of 0 degrees to the first target angle of 10 degrees, compared with no phase shift range constraint, the gain of the constrained phase shift range at the target angle decreases by 0.7102 dB, but its response speed increases by 40%. When switching from the first target angle of 10 degrees to the second target angle of 20 degrees, the gain of the constrained phase shift range at 20 degrees decreases by 0.2856 dB, but the response speed of the beam switching process increases by 1 / 3.

[0109] Figure 4 This is an exemplary schematic diagram comparing the direction of the phase-shifting process of an array antenna beam switching process using a combination of bit and phase-shift range constraints and only bit constraints, as shown in some embodiments of this specification, in a liquid crystal phased array system. Figure 4 As shown, a 1-bit phase shifter can be used directly to control the phase shift range to 180 degrees. The combined constraint of bit position and phase shift range also controls the phase shift range to 180 degrees; therefore, the response times of the two liquid crystal phased arrays are the same. (Combined...) Figure 4 As shown in Table 3, using a 1-bit phase shifter introduces significant quantization errors, which greatly impacts beamforming gain. At a target angle of 10 degrees, the combined constraint improves the gain by 2.0389 dB compared to the 1-bit constraint, and at a target angle of 20 degrees, the improvement is 3.3459 dB.

[0110] In some embodiments of this specification, a beam switching method for a millimeter-wave terahertz liquid crystal phased array is provided. This method optimizes the beam switching process and improves the beam switching speed by combining bit constraints and reducing the phase shift range of the liquid crystal phase shifter. A two-bit phase shifter is used, and its phase shift angle is constrained to balance the phase shifter adjustment speed with system cost, while ensuring beamforming accuracy and main lobe gain. This approach can significantly improve the startup speed and beam switching speed of the liquid crystal phased array.

Claims

1. A beam switching method for a millimeter-wave terahertz liquid crystal phased array, characterized in that, include: S1: By setting the liquid crystal phased array, the number of liquid crystal antennas, array type, and element spacing are obtained; S2: Based on the number of liquid crystal antennas, the array type, and the array element spacing, the transmission signal is obtained by setting the transmission signal and the line-of-sight transmission channel; S3: Perform precoding decoupling on the transmitted signal, set the phase shifter phase based on the analog precoding matrix, and obtain the phase shifter phase setting result; S4: Perform bit constraint on the analog precoding matrix in the transmitted signal to obtain the bit constraint result; S5: Based on the bit constraint results, the quantization angle is reset and the bit is jointly constrained on the analog precoding matrix to obtain the reset phase shifter angle; S6: Based on the reset phase shifter angle, analyze the gain result of beam switching to obtain the beam switching result and complete the beam switching of the millimeter-wave terahertz liquid crystal phased array.

2. The beam switching method for a millimeter-wave terahertz liquid crystal phased array according to claim 1, characterized in that, The expression for the line-of-sight transmission channel is: ； ； ； ； in, Indicates the line-of-sight transmission channel. Represents the normalization factor. Indicates the receiver steering vector. Indicates the target angle at the receiving end. This represents the turning vector of the transmitting end. Indicates the target angle at the transmitting end. This indicates the conjugate transpose. Indicates the number of transmitting antennas. Indicates the number of antennas at the receiving end. This represents the transpose of the receiver's steering vector. This represents the transpose of the steering vector at the transmitting end, where j represents the complex unit. d represents the wavelength of the transmitted wave, and d represents the spacing between array elements.

3. The beam switching method for a millimeter-wave terahertz liquid crystal phased array according to claim 1, characterized in that, The expression for the transmitted signal is: ； ； in, Indicates the transmission of signals. Represents the decoding matrix. Indicates the line-of-sight transmission channel. Represents the analog precoding matrix. Indicates the transmission of a signal. Denotes the first orthogonal matrix. This represents a diagonal matrix whose elements on the main diagonal are singular values. Describes the second orthogonal matrix. This indicates the conjugate transpose.

4. The beam switching method for a millimeter-wave terahertz liquid crystal phased array according to claim 1, characterized in that, The expression for the simulated precoding matrix is: ； in, This represents the transpose of the analog precoding matrix, where j represents the complex unit. d represents the wavelength of the transmitted wave, and d represents the spacing between array elements. Indicates the number of transmitting antennas. This indicates the target angle at the launch end.

5. The beam switching method for a millimeter-wave terahertz liquid crystal phased array according to claim 1, characterized in that, The bit constraint result includes quantization angle constraint, carry probability, and truncation probability, wherein the expression for the bit constraint result is: ； ； in, This indicates a constraint from a quantitative perspective. and Both represent adjacent quantization angles. Indicates the ideal angle. Indicates the interval between quantization angles. This represents the carry probability. This represents the probability of discarding the tail. This indicates the second quantization error. This represents the first quantization error.

6. The beam switching method for a millimeter-wave terahertz liquid crystal phased array according to claim 1, characterized in that, S5 includes: Based on the bit constraint results and phase shift range, the quantization angle of the analog precoding matrix is ​​reset to obtain the reset quantization angle; The phase shifter angle is reset using the reset quantization angle and the bit joint constraint to obtain the reset phase shifter angle.

7. The beam switching method for a millimeter-wave terahertz liquid crystal phased array according to claim 1, characterized in that, The expression for the gain result is: ； in, This indicates the gain of the antenna array at various angles. This indicates the target angle at the receiving end, and P represents the power of the omnidirectional radiating liquid crystal antenna. Represents the analog precoding matrix. This indicates the conjugate transpose. This indicates transpose, j represents the complex unit, and d represents the spacing between antenna elements. Indicates the number of transmitting antennas. The wavelength of the emitted wave is represented by k, and the wave number is represented by k. This indicates the target angle at the launch end.

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