An antenna beamforming method, system and antenna array

Abstract

The embodiment of the specification provides an antenna beam forming method, a system and an antenna array, wherein the antenna beam forming method comprises the following steps: obtaining initial position information of each antenna unit in an initial antenna array and target direction information to be detected; determining a displacement factor corresponding to each antenna unit based on the initial position information; performing displacement, rotation and clipping processing on each antenna unit based on the displacement factor and the like to obtain a target antenna array; determining a steering vector of the target antenna array based on the target direction information, and calculating a beam forming weight of each antenna unit according to the steering vector; and performing weighted synthesis on signals received by each antenna unit based on the beam forming weight, and outputting a target antenna beam. The irregular antenna array can be constructed by performing displacement, rotation and clipping on each antenna unit, so that the channel quantization errors are non-coherently superimposed when being synthesized, thereby low-costly suppressing the influence of the quantization errors of the low-bit quantization full-digital beam forming scheme, and improving the beam synthesis performance.

Description

Technical Field

[0001] The embodiments in this specification relate to the field of antenna technology, and in particular to an antenna beamforming method, system and antenna array. Background Technology

[0002] With the development of wireless communication and digital signal processing technologies, all-digital beamforming technology is being applied in an increasing number of scenarios, such as millimeter-wave communication, satellite internet, and phased array radar. However, all-digital beamforming antenna systems suffer from high hardware costs, high power consumption, and heat dissipation difficulties due to the large number of system channels, large bandwidth, high data rate, and requirements for massive data throughput and real-time processing. This limits their application in scenarios with stringent requirements for power consumption, size, reliability, and radiation resistance (such as low-Earth orbit satellite constellations and spaceborne phased arrays). Therefore, low-bit all-digital beamforming (DBF) technology has been adopted due to its advantages of low power consumption and low cost. In low-bit full DBF schemes, the low quantization accuracy of the signal leads to greater quantization errors in data sampling and conversion, which affect the quality of transmitted data after beamforming and the beamforming performance of the antenna system. Therefore, it is necessary to suppress the impact of quantization errors caused by low-quantization-accuracy data conversion.

[0003] Existing methods for suppressing the impact of signal quantization errors in low-bit full DBF (Dual-Factor Array) often employ dithering techniques, spatial oversampling, and hybrid analog-to-digital converter (ADC) architectures to effectively break the deterministic correlation between quantization noise and the input signal. This makes the quantization error behave more like additive random noise, addressing the "plateau effect" caused by quantization noise saturation in high signal-to-noise ratio (SNR) scenarios. However, these solutions rely on the internal circuitry of specific ADC chips, are limited by the physical size and mutual coupling effects of antenna elements, or are constrained by the cost-effectiveness ratio of high-precision quantization. Therefore, they cannot fully leverage the technical advantages of low-bit full DBF solutions in engineering implementation and applications.

[0004] In summary, existing low-bit full DBF schemes struggle to balance cost and beam generation quality. Summary of the Invention

[0005] In view of this, embodiments of this specification provide an antenna beamforming method. One or more embodiments of this specification also relate to an antenna beamforming system and an antenna array, to address the technical deficiencies existing in the prior art.

[0006] According to a first aspect of the embodiments of this specification, an antenna beamforming method is provided, comprising: Acquire the initial position information of each antenna element in the initial antenna array and the direction information of the target to be detected; Based on the initial position information, determine the displacement factor corresponding to each antenna element; The target antenna array is obtained by shifting each antenna element based on the displacement factor. Based on the target direction information, the steering vector of the target antenna array is determined, and the beamforming weight of each antenna element is calculated according to the steering vector; The signals received by each antenna element are weighted and synthesized based on beamforming weights to output the target antenna beam.

[0007] According to a second aspect of the embodiments of this specification, an antenna beamforming system is provided, including an antenna array and a data processing module. The antenna array includes multiple antenna elements. The antenna array is obtained by shifting each antenna element in an initial antenna array based on a displacement factor, which is determined based on the initial position information of each antenna element in the initial antenna array. An antenna array is used to receive an incident beam through each antenna element and obtain the signal received by each antenna element. The data processing module is used to form a target beam based on the signals received by each antenna element.

[0008] According to a third aspect of the embodiments of this specification, an antenna array is provided, including a plurality of antenna elements and a controller, the controller being used to perform the antenna beamforming method described above; In the antenna array, the physical position of each antenna element is obtained by shifting based on the initial position information and the displacement factor determined based on the initial position information. The controller is configured to calculate the beamforming weight based on the target direction information and perform weighted synthesis of the signals received by each antenna element to output the target antenna beam.

[0009] An embodiment of this specification provides an antenna beamforming method that acquires the initial position information of each antenna element in an initial antenna array and the target direction information to be detected; determines the displacement factor corresponding to each antenna element based on the initial position information; performs displacement processing on each antenna element based on the displacement factor to obtain the target antenna array; determines the steering vector of the target antenna array based on the target direction information, and calculates the beamforming weight of each antenna element according to the steering vector; and performs weighted synthesis of the signals received by each antenna element based on the beamforming weight to output the target antenna beam. This method can construct an irregular antenna array by shifting each antenna element through the displacement factor, so that the position of the antenna element can be adjusted according to its distance from the array center (the displacement factor of the center element is small and the displacement factor of the edge element is large), so that the quantization errors of each channel are non-periodicly superimposed during synthesis, thereby effectively suppressing the quantization sidelobes caused by low-bit quantization, while maintaining the main lobe gain and beam pointing accuracy. Furthermore, the irregular array obtained by shifting naturally has density taper characteristics, which enables the array itself to have sidelobe suppression capabilities. This simplifies or even eliminates the amplitude taper setting of complex weights in beamforming, reduces the computational complexity of beamforming weights, solves the problem that existing low-bit all-digital beamforming schemes cannot balance cost and beam quality, improves the engineering availability of antenna systems in harsh environments such as spaceborne and low-orbit constellations, and achieves the unity of low power consumption, low cost and high-quality beamforming. Attached Figure Description

[0010] Figure 1 This is a flowchart illustrating an antenna beamforming method according to one embodiment of this specification; Figure 2 This is a schematic diagram of the array arrangement of an initial antenna array provided in one embodiment of this specification; Figure 3 This is a schematic diagram of the array arrangement of a target antenna array provided in one embodiment of this specification; Figure 4 This is a schematic diagram of a 1-bit quantized array signal provided in one embodiment of this specification; Figure 5 This is a schematic diagram of a 2-bit quantized array signal provided in one embodiment of this specification; Figure 6 This is a low-bit DBF pattern of an initial antenna array provided in one embodiment of this specification; Figure 7 This is a low-bit DBF pattern of a target antenna array provided in one embodiment of this specification; Figure 8 This is a schematic diagram of an array arrangement generated by a linear function rotation, provided in one embodiment of this specification. Figure 9This is a schematic diagram of a quadratic function rotation generation array arrangement provided in one embodiment of this specification; Figure 10 This is a schematic diagram of a high-order function rotation-generated array arrangement provided in one embodiment of this specification; Figure 11 This is a schematic diagram of the array arrangement of a trimmed target antenna array provided in one embodiment of this specification; Figure 12 This is a schematic diagram of the array arrangement of another trimmed target antenna array provided in one embodiment of this specification; Figure 13 This is a schematic diagram of the array arrangement of another trimmed target antenna array provided in one embodiment of this specification; Figure 14 This is a low-bit DBF normal wavefront section pattern of a trimmed target antenna array provided in one embodiment of this specification; Figure 15 This specification provides a low-bit DBF scanning wavefront pattern of a trimmed target antenna array according to one embodiment. Figure 16 This specification provides a low-bit DBF scanning waveform two-dimensional radiation pattern of a trimmed target antenna array according to one embodiment. Figure 17 This specification provides a low-bit DBF (SNR=-15dB) radiation pattern for a trimmed target antenna array according to one embodiment. Figure 18 This specification provides a low-bit DBF (SNR=-5dB) radiation pattern for a trimmed target antenna array according to one embodiment. Figure 19 This specification provides a low-bit DBF (SNR=5dB) radiation pattern for a trimmed target antenna array according to one embodiment. Figure 20 This specification provides a low-bit DBF (SNR=15dB) radiation pattern for a trimmed target antenna array according to one embodiment. Figure 21 This specification provides a low-bit DBF (SNR=25dB) radiation pattern for a trimmed target antenna array according to one embodiment. Figure 22 This is a schematic diagram of the structure of an antenna beamforming system provided in one embodiment of this specification. Detailed Implementation

[0011] Many specific details are set forth in the following description to provide a full understanding of this specification. However, this specification can be implemented in many other ways than those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this specification. Therefore, this specification is not limited to the specific implementations disclosed below.

[0012] The terminology used in one or more embodiments of this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the one or more embodiments of this specification. The singular forms “a,” “described,” and “the” as used in one or more embodiments of this specification and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in one or more embodiments of this specification refers to and includes any or all possible combinations of one or more associated listed items.

[0013] It should be understood that although the terms first, second, etc., may be used to describe various information in one or more embodiments of this specification, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first may also be referred to as second without departing from the scope of one or more embodiments of this specification, and similarly, second may also be referred to as first. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to a determination."

[0014] Furthermore, it should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in one or more embodiments of this specification are all information and data authorized by the user or fully authorized by all parties. Moreover, the collection, use and processing of related data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and corresponding operation entry points are provided for users to choose to authorize or refuse.

[0015] First, the terms and concepts used in one or more embodiments of this specification will be explained.

[0016] Digital beamforming: Digital beamforming is a technique that uses digital signal processing to sum the amplitude and phase weighted signals received by each antenna element of an antenna array, thereby forming a high-gain receiving beam in the desired direction.

[0017] Low-bit quantization: Low-bit quantization is the process of representing analog signal sample values ​​using fewer binary bits (typically 1 to 3 bits) to reduce the power consumption and data rate of analog-to-digital converters and digital processing devices.

[0018] Quantization error: Quantization error is the difference between the actual amplitude of the analog signal and the quantized digital level. It is caused by a finite number of quantization bits and appears as noise superimposed on the original signal.

[0019] Steering vector: The steering vector is a complex vector that describes the phase difference of the received signal of each antenna element of the antenna array relative to the reference point when a plane wave is incident from a specific direction.

[0020] To meet the needs of high-speed data transmission, multimedia, and mobile communication applications, communication satellites require multi-beam coverage capabilities for both uplink and downlink. For low-Earth orbit (LEO) communication satellites, the performance of phased array antennas, as key components for user communication throughput input and output, characterizes the overall performance of the entire satellite communication system. In LEO satellite payload systems, antennas are required to have wide scanning angles and broadband multi-beam performance to meet the application requirements of LEO satellite communication. The wide-angle scanning capability of phased array antennas provides a wide single-satellite coverage area and helps improve user satellite signal accessibility, while also providing the satellite with the ability to allocate radio resources (power and frequency). Broadband multi-beam phased arrays are extremely important equipment requirements for achieving large communication capacity and improving data throughput. To improve the throughput of the communication system, antennas are required to have high gain and narrow beam performance to improve frequency utilization efficiency, while a greater number of beams and communication bandwidth can serve more users and provide signal coverage across a wide angular domain of the LEO satellite's service area. This requires antennas to simultaneously provide tens, hundreds, or even thousands of flexible or independently controllable beams. Current technology cannot achieve this using analog beamforming. While hybrid beamforming can also form relatively large beams, it requires coordination between the analog and digital components of the system, and the beamforming and scanning directions are limited by the spatial constraints of analog beamforming, making completely independent and flexible beamforming or scanning impossible. The antenna technology that achieves large-scale flexible scanning or independently controllable beamforming functionality and performance is digital beamforming technology.

[0021] Digital beamforming (DBF) technology, specifically for array antennas, utilizes the antenna's aperture to form a receiving beam in the desired direction through digital signal processing, followed by a transmitting beam. DBF is a product of combining antenna beamforming principles with digital signal processing technology, and it is widely used in array signal processing. DBF achieves multiple beams through mathematical operations, is not limited by physical hardware circuitry, and theoretically can achieve an infinite number of beams, making DBF an essential path for achieving larger-scale beamforming. In a full DBF system, all information of the array elements is preserved, and the digitized signals can theoretically be operated on in an unlimited number of stages without degrading signal quality, while also allowing for time delay control to achieve broadband performance. DBF technology has significant advantages in achieving adaptive nulling, simultaneous multi-beam stacking coverage across the entire spatial domain, antenna self-calibration, ultra-low sidelob acquisition, array element pattern correction, and flexible management of power and time-frequency resources. The implementation of full digital beamforming technology (also known as element-level digital beamforming) requires the transmission and reception of metallic radio frequency signals in each element of the array, and the digitization of these signals.

[0022] All-digital beamforming systems face design challenges due to their high channel count, large bandwidth, high data rate, massive data throughput, and real-time processing requirements. These challenges include high hardware costs, high power consumption, difficult heat dissipation, dense system components, and complex software algorithms. The selection of the analog-to-digital converter (ADC) or digital-to-analog converter (DAC) is crucial to system performance. High-precision or high-bit-count (generally not less than 12 bits) conversion devices can achieve a large signal dynamic range and extremely low quantization noise, but they significantly increase power consumption and cost, and increase the load on data transmission and computation. The power consumption of the conversion device is linearly related to the sampling rate, but its relationship with the number of bits is a power of 2; that is, power consumption doubles for every additional bit. In all-digital beamforming (DBF) antenna systems that pursue low power consumption and high integration, using low-bit-count (1-5 bits) ADCs / DACs is an important and feasible technological trend, especially in large-scale arrays and high-frequency broadband applications such as millimeter waves. In millimeter-wave communication (5G / 6G, low signal-to-noise ratio scenarios), typical bit counts of 1-5 bits are selectable. Under low signal-to-noise ratio conditions, 1-2 bit DBF performance may outperform hybrid beamforming, while 3-5 bits achieve a good balance between energy efficiency and spectral efficiency. In satellite communication (high-frequency Q / V bands), typical low bit counts, such as 1 bit (DAC), can also be chosen, combining with a bandpass ΔΣ modulator to directly generate RF signals, simplifying the architecture. The advantages of low-bit DBF are most evident in low signal-to-noise ratio, large-scale antenna scenarios. Unlike terrestrial systems, satellite payloads have extremely stringent requirements for power consumption, size, reliability, and radiation resistance. The core objective of using a low-bit ADC / DAC full DBF solution is to significantly reduce system power consumption and complexity while meeting basic performance requirements, especially for large-scale phased arrays requiring hundreds or even thousands of antenna elements. The power consumption of an ADC / DAC is directly related to its bit count and sampling rate, and power consumption increases exponentially with the number of bits. Reducing the bit depth from 12-14 bits to 1-3 bits significantly reduces power consumption and heat generation per channel, which is crucial for satellites with limited power and heat dissipation. Low-quantization precision DBF (Database Filtering) offers low digital processing power consumption, with data streams ranging from 1 to 5 bits, resulting in substantial reductions in computational and I / O power consumption.

[0023] Satellite energy is extremely precious, and constellation construction places extremely stringent demands on payload cost. Low-bit beamforming (DBF) solutions offer fundamental advantages in reducing power consumption, potentially becoming the only option to meet stringent power budgets, and also providing technical space for optimizing system integration and component costs. Furthermore, in point-to-point high-throughput communication (where the signal-to-noise ratio range is defined), the performance loss of low-bit DBF solutions may be acceptable. In satellite communication, the signal-to-noise ratio (SNR) is typically between 15 and 30 dB. It is generally considered that an SNR above 10 dB is sufficient for normal operation, while above 30 dB ensures reliable data transmission. If the array element size is 300, the SNR output of the receiving antenna element will be between -10 and 5 dB. This operating scenario perfectly matches the technical characteristics of low-bit DBF solutions, which provide a technical approach to achieving low power consumption—a crucial requirement for power-constrained satellite systems. Related research shows that a novel beamforming system using 2-bit quantization achieves an 18.7-fold improvement in area and power efficiency on an ASIC compared to traditional designs. This demonstrates the enormous potential of low-bit solutions in terms of energy efficiency. Adopting a full DBF (Dynamic-Dependent-Frequency) scheme for low-orbit ADCs / DACs in low-Earth orbit broadband communication systems is an innovative technological path that sacrifices some dynamic range in exchange for advantages in power consumption, size, and integration.

[0024] In low-bit ADC / DAC full DBF schemes, larger quantization errors during data sampling and conversion can affect the quality of transmitted data after beamforming and the beamforming performance of the antenna system. To better suppress the impact of signal quantization errors, dithering, spatial oversampling, and hybrid ADC architectures are often used to effectively break the deterministic correlation between quantization noise and the input signal, making the quantization error behave more like additive random noise and solving the "plateau effect" caused by quantization noise saturation in high SNR scenarios. Dithering technology sacrifices the signal-to-noise ratio of a single channel for linearity and achieves array gain through array synthesis. Injecting dithering essentially introduces artificial noise, which directly increases the noise floor of individual antenna elements, leading to a decrease in their individual signal-to-noise ratio. Dithering technology breaks the deterministic correlation between quantization error and the input signal by "randomizing" the quantization process, transforming severe nonlinear distortion (harmonics) into more manageable random additive noise, thereby significantly improving the signal-to-distortion ratio (SDR). Without special handling, the quantization noise of each antenna is highly correlated, and the noise power will change according to N during merging. 2 The proportional increase causes the array gain to disappear. By applying a jitter sequence with a unique initial state (seed) to each antenna, the quantization noise between links can be made independent. After combining, the signal power is proportional to N. 2The noise power increases only by N, thus successfully recovering the array gain of 10lgN. Spatial oversampling, i.e., reducing the antenna spacing to make the element spacing less than half the wavelength (d < λ / 2), is similar to oversampling in time series, providing redundant spatial bandwidth for signal processing. It is a specific technique for "noise shaping" using spatial oversampling. By subtracting the quantization output of one antenna link from the signals of adjacent antennas, the quantization noise is "pushed" away from the signal incident angle (high spatial frequency region). In space-constrained arrays, this technique makes the quantization noise power inversely proportional to the square of the number of antennas (i.e., 1 / N). 2 This involves scaling down the antenna array (to significantly reduce the performance gap with high-resolution systems). Hybrid ADC architectures deploy high-resolution ADCs on a few antennas while retaining low-resolution (1-3 bit) ADCs on the majority of the remaining antennas. The few high-resolution ADCs provide signals with virtually no quantization error, serving as a high-precision reference to aid in calibrating the channel parameters of the entire large array. However, these methods either rely on the internal circuitry of the specific ADC chip, are limited by the physical size and mutual coupling effects of the antenna elements, or are still constrained by the cost-benefit ratio of high-precision quantization, thus failing to fully leverage the technical advantages of a full DBF (decoupling-free) low-bit ADC / DAC scheme in engineering implementation and applications. To suppress the impact of quantization errors in a full DBF scheme for low-bit ADC / DAC, special array arrangements are introduced into antenna array technology to improve beamforming performance.

[0025] In implementing a full DBF (Depth-Field Function) scheme for low-bit ADCs (using a receiving antenna as an example) in traditional regular arrays (such as rectangular or triangular grid arrangements), the array signals exhibit periodicity. Under medium-to-high SNR signal input, the quantization error of the low-bit ADC accumulates on the periodic array signals, generating quantization sidelobes in the antenna radiation pattern, thus degrading the sidelobe suppression performance in the far-field pattern. If an irregular arrangement is used in the antenna array, the quantization error is canceled by quantizing and accumulating the non-periodic signals from the received signals at irregular points using the low-bit ADC. This suppresses the accumulation of periodic quantization errors and achieves quantization sidelobe suppression in the antenna radiation pattern, thereby eliminating the impact of low-bit ADC quantization error on the antenna system to a certain extent. Furthermore, using an irregular arrangement in the low-bit ADC full DBF scheme can also eliminate grating lobes, fully leveraging the advantages of irregular array technology in design flexibility (not limited by grating lobe suppression conditions), large element spacing, array size reduction or enhanced angular resolution, aperture enhancement, and special sidelobe characteristics, achieving a dual improvement in hardware cost and performance. The irregular array design method for low-bit ADC / DAC full DBF antenna systems has advanced technology and engineering application value.

[0026] Previous low-bit ADC / DAC full DBF antenna systems were mainly designed and implemented for regular array antennas, without combining irregular array antennas for technical performance evaluation and in-depth development.

[0027] In view of the above problems, this specification provides an antenna beamforming method and an antenna beamforming system, which will be described in detail in the following embodiments.

[0028] See Figure 1 , Figure 1 A flowchart of an antenna beamforming method according to an embodiment of this specification is shown, including the following specific steps: Step 102: Obtain the initial position information of each antenna element in the initial antenna array and the direction information of the target to be detected.

[0029] The embodiments in this specification are applied to scenarios such as wireless communication, spaceborne antennas, low-orbit satellite communication, spaceborne phased array radar, and millimeter-wave base stations.

[0030] The initial antenna array is an antenna array in which the antenna elements have not been shifted. The antenna elements in the initial antenna array are evenly arranged at equal intervals.

[0031] To illustrate, for low-Earth orbit satellite communication applications and satellite payload design requirements, a low-bit digital beamforming engineering application of a Ku-band all-digital beamforming receiving phased array antenna is presented, covering the operating frequency of 14.0~14.5GHz. The embodiments in this specification provide a comparison and evaluation of the antenna beamforming performance under 1-bit and 2-bit ADC signal conversion models.

[0032] Based on the antenna gain, the antenna element size N in the antenna array is determined to be greater than 400. The operating frequency F in the antenna performance analysis is set to 14.5 GHz, and the beam scanning angle range (maximum off-axis scanning angle θ) is also set. scan The angle is 50°.

[0033] Indicatively, Figure 2 A schematic diagram of the array arrangement of an initial antenna array provided in an embodiment of this specification is shown. Figure 2 As shown, in the initial antenna array layout selection, d is chosen. x =d y =9mm, N x =N y =24, including 24×24 uniformly arranged antenna elements.

[0034] The initial position information consists of the coordinates of each antenna element within the antenna array plane (such as polar or Cartesian coordinates). For example, for the initial antenna array of the aforementioned 24×24 antenna elements, with the array's geometric center as the origin, the coordinates of the element in the i-th row and j-th column are x... i = (i-12.5)·d x y j= (j-12.5)·d y d x and d y The spacing between the antenna array along the x-axis and y-axis is determined by the beam scanning range.

[0035] The target direction information is the desired direction of the receiving beam, including the elevation angle θ and the azimuth angle φ. For example, θ=30° and φ=0° means that the beam pointing to the array normal is 30° in front and located in the xz plane.

[0036] Optionally, one way to obtain the initial position information of each antenna element in the initial antenna array is to automatically generate the coordinates of each element based on the array's geometric parameters (number of rows, number of columns, spacing). Another way is to read the calibrated actual position information through external measurement or a configuration file. This specification does not limit this approach in the embodiments.

[0037] Optionally, one way to obtain the target direction information to be detected is to obtain the desired beam pointing angle from radar search commands or a communication system beam scheduler. Another way is to estimate the signal beam direction in real time using a direction-finding algorithm as the target direction. This specification does not limit the embodiments in this way.

[0038] Step 102 obtains the initial position information of each antenna element in the initial antenna array and the direction information of the target to be detected, which provides a data basis for subsequently determining the displacement factor corresponding to each antenna element and determining the steering vector of the target antenna array.

[0039] Step 104: Based on the initial position information, determine the displacement factor corresponding to each antenna element.

[0040] The displacement factor is a parameter used to shift the positional information of each antenna element. Its value depends on the polarity of the antenna element and the preset displacement parameter; the larger the polarity, the larger the displacement factor. For example, the displacement factor of antenna element i can be defined as... ,in The displacement length (i.e., displacement parameter) and the polar diameter With the same dimensions, the degree of gradual change in the displacement of elements in the array can be achieved by changing the displacement length.

[0041] Optionally, one way to determine the displacement factor corresponding to each antenna element based on the initial position information is to calculate the displacement factor using a Gaussian cumulative distribution function based on the ratio of the element's polar radius to a preset displacement length. Another way is to normalize the element's polar radius and then obtain the displacement factor through a linear or piecewise linear function mapping. This specification does not limit the specific implementation of this method.

[0042] For example, suppose the initial antenna array is a 24×24 uniform rectangular grid, and the element spacing d x =d y =9mm, the array center is located at the geometric center. For a cell located at the array corner, if its coordinates are (10mm, 10mm), then the polar radius r i = =10 mm; for a cell located at the center of the array, the polar radius r i =0mm. Based on the array's electrical performance requirements, the preset displacement length σ = 58.6mm (approximately 0.4 times the maximum pole diameter). Then, the displacement factor for each element is calculated using the above displacement factor calculation expression. For the center element, α... i =0.

[0043] Step 104 determines the displacement factor corresponding to each antenna element based on the initial position information. This allows for different movement amplitudes to be assigned according to the radial position of the element in the array, providing a prerequisite for subsequent displacement processing of each antenna element.

[0044] Step 106: Shift each antenna element based on the displacement factor to obtain the target antenna array.

[0045] The shifting process involves moving each antenna element from its initial position along a preset direction. The shift distance is equal to the displacement factor multiplied by the coordinate value of the antenna element. For example, the coordinate position of antenna element i... Using displacement factor Perform non-uniform displacement processing to obtain new coordinate positions. : .

[0046] The target antenna array is an irregularly arranged antenna array obtained after shifting, where the positions of its elements no longer maintain equal spacing, thus breaking the spatial periodicity of quantization error. For example, after the original uniform array is shifted, the central region elements remain almost unchanged, while the edge elements shift outward, forming a density tapering effect with denser elements at the center and sparser elements at the edges.

[0047] Indicatively, Figure 3 A schematic diagram of the arrangement of a target antenna array in an embodiment of this specification is shown.

[0048] refer to Figure 3The spacing between antenna elements in the target antenna array is no longer uniform, resulting in an irregular array arrangement. This irregular array arrangement exhibits a density taper characteristic, meaning the element density in the central region is greater than that in the outer regions, and the original straight lines of the array grating are bent into star-shaped curves. Due to the extension effect of the non-uniform displacement processing, the aperture of the target antenna array is larger than that of the initial antenna array, and the outer envelope of the new array arrangement is no longer rectangular. The average element spacing of this target antenna array is larger, and due to the non-periodicity of the antenna elements, it has grating lobe suppression capability, enabling it to provide higher angular resolution in the antenna beam.

[0049] Optionally, one way to obtain the target antenna array by shifting each antenna element based on the displacement factor is to move it outward along the polar radius direction of each element, with the moving distance being the displacement factor multiplied by a preset maximum step size. Another way is to keep the polar angle constant in polar coordinates and increase the polar radius by the displacement factor multiplied by a preset step size. This specification does not limit the implementation of this method.

[0050] For example, assume the initial antenna array includes N x ×N y The antenna elements are uniformly arranged, and their spacing on the x-axis is determined by the beam scanning range as d. x The spacing on the y-axis is d y The array center is located at the geometric center (0, 0). For any element x i The number of rows along the x-axis and y-axis are respectively m , n Its initial coordinates , ,in , .

[0051] For any antenna element, based on the preset polar radius and preset displacement parameters of the antenna element, substitute them into the displacement factor calculation formula. The displacement factor α is calculated, and the coordinates become x after the shift. i =x i (1+α), y i ′=y i (1+α). For antenna elements near the center of the array, the moving distance is relatively small; for elements located at the corners of the array, the moving distance is relatively large.

[0052] Step 106 performs shifting processing on each antenna element based on the displacement factor to obtain the target antenna array, which can change the array arrangement from regular to irregular, laying a structural foundation for subsequent suppression of sidelobes caused by low-bit quantization.

[0053] Step 108: Based on the target direction information, determine the steering vector of the target antenna array, and calculate the beamforming weight of each antenna element according to the steering vector.

[0054] The steering vector of the target antenna array is a complex vector describing the relative phase difference generated on each antenna element after the plane wave from the target direction is shifted.

[0055] The beamforming weights are coefficients used to adjust the amplitude and phase of the received signals from each antenna element, so that the signals from the target direction are superimposed in phase.

[0056] Specifically, the guide vector can be calculated using the following formula: ,in Let i be the coordinate position of cell i in the planar array, 1 , denoted as the number of elements in the planar array, and k is the free space wavenumber 2π / λ.

[0057] The array signal is converted from analog to digital, and its I / Q signals are acquired and digitally quantized using a low-bit quantization model to obtain the quantized array signal. : , in, For complex signal quantization functions, and For real quantization functions, for 1-bit quantization, The function is the symbolic function sign, that is: .

[0058] For 2-bit quantization The function is The function is implemented by normalizing the maximum amplitude of the complex signal and dividing it into equal-step segments, that is: ,in .

[0059] For b-bit quantization The function is Function, that is: where n is an integer, and .

[0060] Quantized array signal Beamforming can be achieved by performing signal weighting and vector addition operations, and the received signal corresponding to that beam can be output. The complex weighting values... Optional beam pointing setting (target direction: and The corresponding guide vector The complex conjugate of the vector can also be used to perform magnitude weighting on the vector, i.e. ,That This adds a weighted real value to the magnitude of unit i. In a simplified system implementation, it can be set to... .

[0061] In practical implementations, the complex weights can also be obtained through array synthesis or optimization methods. To achieve special radiation performance, such as beamforming and anti-interference.

[0062] Keep this adjusted weight value By performing the same quantization, weighting, and vector addition operations on the array signal corresponding to the steering vector in the antenna's receiving spatial domain, the antenna receiving spatial radiation pattern of this all-digital beamforming antenna system can be obtained. This can be achieved by simultaneously setting multiple complex weighting values. By performing parallel computation, the performance of a multi-beam antenna can be obtained.

[0063] Step 108 determines the steering vector of the target antenna array based on the target direction information, and calculates the beamforming weight of each antenna element according to the steering vector. This provides the correct phase compensation coefficient for subsequent weighted synthesis of quantized signals, ensuring coherent accumulation of signals in the desired direction.

[0064] Step 110: Based on the beamforming weights, the signals received by each antenna element are weighted and synthesized to output the target antenna beam.

[0065] The target antenna beam is a beam formed in the target direction, and its sidelobes and quantization sidelobes are effectively suppressed.

[0066] Optionally, one way to weight and synthesize the signals received by each antenna element based on beamforming weights and output the target antenna beam is to multiply each quantized signal by its corresponding complex weight in the digital domain and then sum them to obtain a single scalar output. Another way is to simultaneously perform parallel weighted summation on multiple sets of weights with different directions to obtain multiple independent beams. This specification does not limit the scope of this method in the embodiments.

[0067] Specifically, the signals received by each antenna element are weighted and synthesized, including the following steps: First, the signal is separated into I and Q signals to obtain in-phase (I) and quadrature (Q) components. Then, low-bit quantization is performed on both I and Q signals. If the input signal for signal conversion is a complex signal s, then I = real(s) and Q = img(s), meaning the in-phase (I) and quadrature (Q) components are the real and imaginary parts of the complex signal s, respectively. In low-bit quantization, the I and Q signals are quantized according to the set signal conversion bit values. Here, we take 1-bit and 2-bit signal quantization as examples. 1-bit quantization is implemented using the sign function, i.e.: .

[0068] 2-bit quantization is achieved by normalizing the maximum amplitude of the complex signal and dividing it into equal-step segments, i.e.: ,in .

[0069] For bit quantization of b (b≥3), there is a quantization function. where n is an integer, and .

[0070] Indicatively, Figure 4 This specification shows a schematic diagram of an array signal after 1-bit quantization in an embodiment of the present specification. Figure 5 A schematic diagram of a 2-bit quantized array signal is shown in an embodiment of this specification. Figure 4 and Figure 5 It can be seen that the precision of 2-bit quantization is twice that of 1-bit quantization.

[0071] Indicatively, Figure 6 The low-bit DBF pattern of an initial antenna array in an embodiment of this specification is shown. Figure 7 The low-bit DBF pattern of a target antenna array in an embodiment of this specification is shown.

[0072] Depend on Figure 6 and Figure 7 It can be seen that at azimuth angles of -50 degrees and 0 degrees, the normalized power of the target antenna array is significantly reduced. The target antenna array after shifting exhibits a density tapered distribution with a dense center and sparse edges. This geometric tapering itself has low sidelobe characteristics, which is equivalent to amplitude tapering. This indicates that the target antenna array significantly reduces the quantization sidelobe level caused by low-bit quantization, thereby improving beam quality and verifying the effectiveness of this method in suppressing quantization sidelobes and improving antenna radiation patterns.

[0073] The following demonstrates the performance differences between the initial antenna array and the target antenna array in a low-bit digital beamforming system. In the signal model, a signal-to-noise ratio (SNR) of 20 dB is set, and a low-bit quantization model is used to generate the quantized array signal, which is then used as the input for beamforming the received signal. In digital beamforming, setting a complex weight value (with the same amplitude) for the beam pointing at 50° enables the formation of the beam pointing to that direction and achieves efficient reception of the directional signal. Thus, the array factor patterns of both arrays at this scanning wavelength were calculated. It can be found that both arrays can form a beam pattern with the main lobe pointing towards the target angle after low-bit beamforming. In beamforming after low-bit signal quantization, the initial antenna array produces quantization sidelobes due to the periodicity of the array signal quantization error, and the level of these quantization sidelobes is significantly higher than that of other sidelobes. In contrast, the target antenna array, due to the disruption of the periodicity of the array signal quantization error by the array arrangement, suppresses the corresponding quantization sidelobes, and the low-bit quantized beam pattern at this wavelength is very close to the ideal quantized beam pattern, indicating that the influence of signal quantization error is suppressed. At the same time, the density weighting of the array arrangement reduces the level of the first sidelobe of the antenna pattern.

[0074] Step 110 weights and synthesizes the signals received by each antenna element based on beamforming weights to output the target antenna beam. This method coherently superimposes the quantized signals from each channel in the desired direction. Simultaneously, the irregular array disrupts the periodicity of the quantization error, dispersing the energy of the quantization sidelobes, thus achieving a beam quality close to that of high-bit systems under low-bit conditions. The use of a low-bit quantization model significantly reduces power consumption and hardware costs in the signal conversion process, decreases the computational load of the digital processing unit and the amount of input / output data, achieving a dual reduction in cost and power consumption for the all-digital beamforming antenna system.

[0075] In this embodiment, the initial position information of each antenna element in the initial antenna array and the target direction information to be detected are obtained; based on the initial position information, the displacement factor corresponding to each antenna element is determined; based on the displacement factor, each antenna element is shifted to obtain the target antenna array; based on the target direction information, the steering vector of the target antenna array is determined, and the beamforming weight of each antenna element is calculated according to the steering vector; based on the beamforming weight, the signals received by each antenna element are weighted and synthesized to output the target antenna beam. This method can construct an irregular antenna array by shifting each antenna element through the displacement factor, so that the position of the antenna element can be adjusted according to its distance from the center of the array (the displacement factor of the center element is small and the displacement factor of the edge element is large), so that the quantization errors of each channel are incoherently superimposed during synthesis, thereby effectively suppressing the quantization sidelobes caused by low-bit quantization, while maintaining the main lobe gain and beam pointing accuracy. Furthermore, the irregular array obtained by shifting naturally has density taper characteristics, which enables the array itself to have sidelobe suppression capabilities. This simplifies or even eliminates the amplitude taper setting of complex weights in beamforming, reduces the computational complexity of beamforming weights, solves the problem that existing low-bit all-digital beamforming schemes cannot balance cost and beam quality, improves the engineering availability of antenna systems in harsh environments such as spaceborne and low-orbit constellations, and achieves the unity of low power consumption, low cost and high-quality beamforming.

[0076] In one optional embodiment of this specification, the target antenna array is pre-set with physical parameters and performance parameters; Before step 104, the following is also included: Based on physical and performance parameters, determine the displacement parameters corresponding to the initial antenna array; Step 104 includes the following specific steps: Based on the initial position information, the polar diameter of each antenna element is determined; Based on the polar diameter of each antenna element and the displacement parameters corresponding to the initial antenna array, the displacement factor corresponding to each antenna element is determined.

[0077] Physical parameters are indicators that describe the geometric dimensions and element arrangement constraints of the antenna array, and may include array aperture, minimum element spacing, operating wavelength, etc.

[0078] Performance parameters are indicators that describe the expected radiation characteristics of an antenna array, and may include the desired beamwidth, maximum sidelobe level, quantization sidelobe suppression requirements, etc.

[0079] The displacement parameter is a scale factor used to control the rate of change of position information of each antenna element. It can be the displacement length σ, which has the same dimension as the polar diameter and determines how fast the displacement factor changes with the polar diameter.

[0080] Optionally, one way to determine the displacement parameters corresponding to the initial antenna array based on physical and performance parameters is to obtain the displacement length by inversely solving the displacement factor expression based on the maximum pole radius of the array and the desired target value of the edge displacement factor. Another way is to optimize through simulation, aiming to minimize the quantization sidelobes, and scan the displacement parameter values ​​under the constraints of physical parameters. This specification does not limit the embodiments in this way.

[0081] The polar radius is the radial distance from the antenna element to the array center (or reference point) in the array plane, which is obtained from the initial position information through coordinate transformation.

[0082] Optionally, one way to determine the polar radius of each antenna element based on the initial position information is to calculate the Euclidean distance of each element's coordinates with the array's geometric center as the origin. Another way is to calculate the weighted distance with the phase center or feed reference point as the origin. This specification does not limit the embodiments to this method.

[0083] Specifically, in the embodiments of this specification, an equally spaced rectangular grid planar array is generated based on the operating frequency (i.e., based on the mission purpose (such as communication, navigation) and payload design), and the coordinate position of element i in the Cartesian coordinate system is as follows: , ,in and This represents the number of rows in the planar array along the x-axis and y-axis. , The total array size is ,and , and The spacing of the rectangular grid along the x-axis and y-axis is determined by the beam scanning range. Thus, the polar radius of antenna element i in polar coordinates is... .

[0084] For example, the displacement length is set according to the physical and performance parameters of the target antenna array, the corresponding displacement factor is calculated according to the polar radius value of each antenna element, and non-uniform displacement processing is performed to obtain the target antenna array.

[0085] In the embodiments of this specification, the displacement parameters corresponding to the initial antenna array are determined based on physical and performance parameters, and the polar diameter of each antenna element is determined based on the initial position information. Based on the polar diameter of each antenna element and the displacement parameters corresponding to the initial antenna array, the displacement factor corresponding to each antenna element is determined. This enables the generation process of the displacement factor to adaptively match the geometric constraints and beam quality requirements of the actual array, avoiding performance degradation or array geometric violations caused by blindly selecting displacement parameters. Thus, while ensuring the minimum spacing between elements and the aperture utilization rate, effective suppression of quantization sidelobes is achieved, improving the engineering designability and robustness of the low-bit all-digital beamforming system.

[0086] In one optional embodiment of this specification, step 106 includes the following specific steps: Based on the displacement factor, the target position information corresponding to each antenna element is determined; Based on the target location information, each antenna element is shifted to obtain the target antenna array.

[0087] The target position information consists of the coordinates corresponding to the displacement of each antenna element, which can be represented using polar coordinates or Cartesian coordinates.

[0088] Optionally, one way to determine the target position information corresponding to each antenna element based on the displacement factor is to move outward along the polar radius direction of the initial position, with the moving distance equal to the displacement factor multiplied by a preset maximum step size, while keeping the polar angle unchanged. Another way is to offset the x and y coordinates respectively according to the displacement factor in a Cartesian coordinate system. This specification does not limit the implementation of this method.

[0089] Specifically, the position of element i is processed by a displacement factor to achieve non-uniform displacement, resulting in a new coordinate position. :

[0090] Following the above processing method, the target antenna array is obtained by shifting all antenna elements in the initial antenna array.

[0091] Indicatively, Figure 3 This specification shows a schematic diagram of the array arrangement of a target antenna array.

[0092] refer to Figure 3 The target antenna array is an irregular array surface arrangement, the spacing between elements is no longer equal, and the array surface exhibits a density tapering characteristic, that is, the element density is the highest at the center of the array surface, and the element density decreases as the element is farther away from the center of the array surface.

[0093] In the embodiments of this specification, the target position information corresponding to each antenna element is determined based on the displacement factor; based on the target position information, each antenna element is shifted to obtain the target antenna array. This can transform the dimensionless weight of the displacement factor into an actual spatial coordinate offset, making the displacement of the central region extremely small and the displacement of the edge region relatively large, thereby constructing an irregular geometric structure with a dense center and sparse edges. This provides a physical carrier for subsequently breaking the periodicity of quantization error and suppressing quantization sidelobes, while avoiding the mutual coupling deterioration caused by excessively small element spacing, thus ensuring the electromagnetic compatibility performance of the array.

[0094] In one optional embodiment of this specification, after step 106, the method further includes: The antenna elements in the target antenna array are rotated relative to each other to obtain the rotated target antenna array. Step 108 includes: Based on the target direction information, the steering vector of the rotated target antenna array is determined, and the beamforming weight of each antenna element is calculated according to the steering vector.

[0095] Relative rotation of each antenna element in the target antenna array involves deflecting each element around the array center (or reference point) by a certain angle in the azimuth direction, thereby further disrupting the regularity of the array and enhancing the incoherence of the quantization error. For example, an element that has already been moved radially outward is then rotated circumferentially by a small angle related to its polar radius.

[0096] The rotated target antenna array is a new irregular array obtained after rotation transformation. Its element positions in polar coordinates are characterized by an unchanged polar radius and an increased polar angle with an increment related to the polar radius. For example, the rotated array exhibits a spiral or radially twisted arrangement.

[0097] Optionally, one way to obtain a rotated target antenna array by relatively rotating each antenna element in the target antenna array is to add a constant increment proportional to the polar radius to the polar angle of each antenna element. Another way is to calculate the rotation angle according to a nonlinear function (such as square, exponential, etc.) so that elements with different radial distances obtain different degrees of twist. The embodiments in this specification do not limit this approach.

[0098] For example, for the target antenna array obtained by displacement, a rotation angle is selected and the maximum polar radius of the target antenna array is determined. The rotation angle and the maximum polar radius are substituted into a rotation function (such as a linear function, a quadratic function, or a higher-order function). Then, the polar radius corresponding to each antenna element is substituted into the above rotation function to obtain the polar angle increment corresponding to each antenna element. Based on the polar angle increment, each antenna element is rotated relative to the others. After this rotation operation, the array as a whole presents a spiral twist, with the central element rotating less and the edge element rotating more, which further enhances the non-periodicity of the array and destroys the symmetry that may remain after simple radial displacement, thereby further suppressing the quantization sidelobe.

[0099] In the embodiments of this specification, by rotating the target antenna array, an azimuth-directed irregular modulation is introduced on the basis of the irregular array constructed by radial shift, further disrupting the periodicity and symmetry of the array, making the phase distribution of quantization error of each antenna element more random. As a result, the incoherent superposition effect of quantization error is more sufficient during beamforming weighted synthesis, further suppressing the quantization sidelobe level, while avoiding parasitic beams caused by symmetrical structure residues, thus improving the beam quality of the low-bit all-digital beamforming system.

[0100] In one optional embodiment of this specification, the antenna elements in the target antenna array are rotated relative to each other to obtain a rotated target antenna array, including: Based on the position information of each antenna element in the target antenna array, determine the polar angle increment corresponding to each antenna element; Based on the polar angle increment and the pre-constructed rotation function, each antenna element in the target antenna array is rotated to obtain the rotated target antenna array.

[0101] The polar angle increment is the angle value that each antenna element needs to add based on its original polar angle.

[0102] Optionally, one way to determine the polar angle increment corresponding to each antenna element based on the position information of each antenna element in the target antenna array is to set the polar angle increment to be proportional to the polar radius. Another way is to set the polar angle increment to be proportional to the displacement factor. This specification does not limit the specific implementation of this method.

[0103] A rotation function is a mathematical expression describing the mapping relationship between the polar angle increment and the antenna element position (such as polar radius, polar angle, or displacement factor). For example, rotation function The polar angle increment Δθ is defined. i With polar radius To achieve nonlinear rotations, a monotonically increasing linear function is often chosen, but quadratic or higher-order functions can also be used. For example, a linear function can be... A quadratic function can be defined as Higher-order functions can be ,in The rotation angle is a constant, while The maximum value of r. , And so on. After rotating each antenna element in the target array, the coordinate position of each antenna element i in the Cartesian coordinate system is... : , .

[0104] Indicatively, Figure 8 This specification illustrates a schematic diagram of an array arrangement generated by the rotation of a linear function, as shown in an embodiment of the present specification. Figure 9 This document shows a schematic diagram of a quadratic function rotation generation array arrangement as described in an embodiment of the present specification. Figure 10 A schematic diagram of a high-order function rotation generation array arrangement is shown in an embodiment of this specification.

[0105] according to Figure 8 It can be seen that using linear function rotation to induce a uniform helical twist in the array, with a small rotation in the central region and a large rotation in the edge region, breaks the symmetry that may remain after radial displacement; according to Figure 9 and Figure 10 It is known that using quadratic or higher-order function rotation achieves nonlinear variation of the polar angle increment with the polar radius, making the array geometry more complex and disordered. This additional non-uniformity in the polar angle direction further disrupts the spatial periodicity of the quantization error, making the phase distribution of the quantization error of each antenna element more random during beamforming weighted synthesis. This allows the quantization sidelobe energy to be more thoroughly dispersed into the wide-angle substrate, further reducing the peak sidelobe level while keeping the main lobe width and gain essentially unchanged.

[0106] For example, let the rotation function be Δθ i =a×r i ′ / Rmax, where Rmax is the maximum pole radius of the array, a is the maximum rotation angle of the edge antenna elements in the array, which can be preset according to actual needs, r i Let r' be the polar radius of each antenna element in the array. i Substituting the above rotation function, we obtain the polar angle increment for each antenna element. After relative rotation of each antenna element based on the polar angle increment, the new polar angle of each element is θ. i =θ i +Δθ i The polar radius remains unchanged. Convert the rotated polar coordinates back to Cartesian coordinates: x i ′′=r i cosθ i ′,y i ′′=ri sinθ i ′, which means obtaining the rotated target antenna array.

[0107] In the embodiments of this specification, based on the position information of each antenna element in the target antenna array, the polar angle increment corresponding to each antenna element is determined. Based on the polar angle increment and a pre-constructed rotation function, each antenna element in the target antenna array is rotated to obtain the rotated target antenna array. This allows for the introduction of a gradual rotation in the azimuth direction on top of the radial irregular displacement, causing the array geometry to lose any possible reflection or translational symmetry. This disrupts the spatial periodicity of the quantization error, making the quantization error exhibit more thorough randomness during beamforming, significantly reducing the peak level of the quantization sidelobes while maintaining the main lobe width and gain essentially unchanged. This improves the angular resolution and anti-interference capability of the low-bit all-digital beamforming system. By introducing rotation operations based on linear, quadratic, and higher-order functions, linear and nonlinear rotations of the shifted antenna array can be achieved, providing flexibility for the construction and optimization of the antenna array model and facilitating the evaluation of the technical characteristics of irregular antenna arrays.

[0108] In one optional embodiment of this specification, after rotating the antenna elements in the target antenna array relative to each other to obtain the rotated target antenna array, the method further includes: Based on the preset antenna layout and beam scanning parameters, the rotated antenna array is trimmed to obtain the trimmed target antenna array. Based on the target direction information, the steering vector of the rotated target antenna array is determined, and the beamforming weight of each antenna element is calculated according to the steering vector, including: Based on the target direction information, the steering vector of the clipped target antenna array is determined, and the beamforming weight of each antenna element is calculated according to the steering vector.

[0109] The preset antenna layout is the pre-designed external geometry and / or mounting boundary of the target antenna array. For example, the geometry can be rectangular, circular, elliptical, etc., and the mounting boundary can be the maximum aperture of the antenna array.

[0110] Beam scanning parameters refer to the maximum scanning angle range and scanning method that the antenna array needs to cover during operation. These parameters can include the elevation scanning range, azimuth scanning range, etc. For example, it may be required that the antenna achieves grating-lobe-free scanning within an elevation range of ±60° and an azimuth range of 360°.

[0111] Trimming a rotated antenna array refers to removing or disabling antenna elements located outside the preset antenna layout boundaries to make its shape conform to actual installation or scanning performance requirements. For example, deleting elements that exceed the circular envelope after rotation results in an approximately circular, irregular array.

[0112] Indicatively, Figure 11 A schematic diagram of the array arrangement of a trimmed target antenna array is shown in an embodiment of this specification. Figure 12 This document shows a schematic diagram of the array arrangement of another trimmed target antenna array in an embodiment of this specification. Figure 13 This diagram illustrates the array arrangement of yet another trimmed target antenna array in an embodiment of this specification.

[0113] The following is passed Figures 14-16 right Figure 13 Performance analysis of the target antenna array in the middle: Indicatively, Figure 14 This specification shows a low-bit DBF normal wavefront cross-section pattern of a trimmed target antenna array according to an embodiment of the present specification. Figure 15 This specification shows a low-bit DBF scan waveform cross-section pattern of a trimmed target antenna array according to an embodiment of the present specification. Figure 16 The diagram shows a low-bit DBF scan waveform of a two-dimensional radiation pattern of a trimmed target antenna array according to an embodiment of this specification.

[0114] Depend on Figure 14 , Figure 15 and Figure 16 As can be seen, compared with the beam pattern of the uncropped target antenna array, although the size of the uncropped target antenna array is reduced, it still has density taper characteristics and irregular array arrangement characteristics. It can be found that not only are the quantization sidelobes corresponding to the signal quantization error caused by low-bit signal quantization suppressed, but the overall sidelobe suppression performance is also improved. Through the use of this digital beamforming system and method, the beam pattern of low-bit quantization is very close to that of ideal quantization, the influence of signal quantization error is suppressed, and the sidelobe performance improvement based on density taper is achieved.

[0115] Indicatively, the following refers to Figure 13 The target antenna array shown below is a cropped array. Taking the scanning wave position as an example, the simulation results of the beam pattern of the receiving antenna element with different SNR (-15~25dB) signals in the low bit DBF system are given. The impact of different SNR on its low bit DBF performance is shown in 10dB intervals.

[0116] Indicatively, Figure 17 The low-bit DBF (SNR=-15dB) radiation pattern of a trimmed target antenna array according to an embodiment of this specification is shown. Figure 18 The low-bit DBF (SNR=-5dB) radiation pattern of a trimmed target antenna array according to an embodiment of this specification is shown. Figure 19The low-bit DBF (SNR=5dB) radiation pattern of a trimmed target antenna array according to an embodiment of this specification is shown. Figure 20 The low-bit DBF (SNR=15dB) radiation pattern of a trimmed target antenna array according to an embodiment of this specification is shown. Figure 21 The diagram shows the low-bit DBF (SNR=25dB) radiation pattern of a trimmed target antenna array according to an embodiment of this specification.

[0117] from Figures 17-21 The simulation results show that in extremely low SNR scenarios, improving signal quantization accuracy has a negligible effect on antenna performance, while in other SNR scenarios... Figure 13 The cropped target antenna arrays shown in the figure can suppress the impact of low-bit quantization errors on beam performance, with no obvious quantization sidelobes generated, achieving the goal of low-sidelobe wide-angle scanning performance in all-digital antennas. This reduces the excessive investment in signal quantization accuracy during system design, providing important technical space for comprehensive performance optimization of all-digital systems, and also reflects the improvement of technical advantages and system competitiveness. Simulation results of low-bit DBF beam performance for different SNR signals are also provided.

[0118] It should be noted that the above regarding Figures 17 to 21 The description of the radiation patterns of the target antenna array under various SNR values ​​is only for demonstrating the performance of the target antenna array and does not constitute a limitation on this scheme.

[0119] Optionally, based on a preset antenna layout and beam scanning parameters, one way to obtain the trimmed target antenna array is to calculate the position of each element, retain the elements located within the preset geometry, and delete the external elements. Another way is to determine the equivalent aperture utilization rate according to the beam scanning parameters, retain the elements that contribute the most, and remove redundant edge elements. This specification does not limit the specific implementation of this method.

[0120] For example, the preset antenna layout is a circular aperture, and some elements in the rotated target antenna array are located outside this circle. These elements located outside the circle are removed, resulting in a trimmed circular array, thus reducing the total number of elements. The trimmed array still maintains the density tapered characteristic of being denser at the center and sparser at the edges, and the periodicity is further disrupted due to the removal of incomplete elements at the edges, while simultaneously meeting the mechanical installation requirements of the satellite payload for a circular aperture.

[0121] In the embodiments of this specification, the rotated target antenna array is trimmed based on a preset antenna layout and beam scanning parameters to obtain a trimmed target antenna array. This allows the irregular array to adapt to geometric constraints in actual engineering (such as circular aperture, rectangular cut, etc.). Simultaneously, by removing edge elements, the non-periodicity of the array is further enhanced, large-angle sidelobes during scanning are reduced, beam quality at wide scanning angles is improved, and the number of redundant channels is reduced, thus lowering system power consumption and data volume. This not only achieves unequal spacing operations in the radial direction of the array surface but also provides an irregular enhancement implementation in the azimuth direction of the antenna array, and obtains an antenna array with a certain regular structural envelope by trimming the irregular antenna array.

[0122] The target antenna arrays described above, including the rotated and trimmed arrays, all exhibit a non-periodic arrangement of array elements. This enables suppression of grating lobes in the radiation pattern and quantization sidelobes caused by low-bit ADC quantization errors. Furthermore, as three types of density-tapered arrays, they possess unique sidelobe suppression capabilities independent of amplitude tapering implementation methods. The specific array arrangement can be controlled by setting and adjusting relevant parameters, offering flexibility and speed in design. Simultaneously, since these three irregular antenna arrays are obtained by modifying the original rectangular grating planar array (initial antenna array), their element mapping relationships are clear. This facilitates the design and implementation of the mapping network between the regularly arranged RF system, digital modules, and antenna elements within the antenna. The regularly arranged RF system and digital modules can utilize and integrate existing mature design schemes and implementation techniques, which also benefits the modularization and clear interconnection of various functional parts in the all-digital beamforming antenna system.

[0123] In one optional embodiment of this specification, prior to step 110, the method further includes: Based on the signal-to-noise ratio corresponding to the signal received by each antenna element, complex Gaussian white noise is added to the signal received by each antenna element to obtain the signal received by each antenna element with added complex Gaussian white noise. Step 110 includes: The signals received by each antenna element with added complex Gaussian white noise are weighted and synthesized based on beamforming weights to output the target antenna beam.

[0124] The signal-to-noise ratio (SNR) of the signal received by each antenna element is the ratio of signal power to noise power, expressed in decibels (dB), and is used to control the power of superimposed noise. For example, when the SNR is 10 dB, the variance of the superimposed complex Gaussian white noise is 0.1 times the signal power.

[0125] Complex white Gaussian noise is a complex random signal whose real and imaginary parts are independent, both following a zero-mean Gaussian distribution, and with a constant power spectral density. It is used to simulate thermal noise in the receiving channel and as a jitter source to break the correlation of quantization errors. For example, the real and imaginary parts of complex white Gaussian noise are Gaussian random numbers with variance σ² / 2, respectively.

[0126] Optionally, one way to add complex Gaussian white noise to the signals received by each antenna element based on the signal-to-noise ratio (SNR) of each received signal is to calculate the noise variance based on the SNR and generate a complex Gaussian white noise sequence of the same length, which is then superimposed on the signal. Another way is to superimpose a very small amplitude of white noise only on the signal before low-bit quantization to eliminate the relationship between quantization error and signal harmonics. This specification does not limit the implementation of this method.

[0127] For example, assuming a signal-to-noise ratio requirement of 15 dB and an average signal power of 1 watt, the noise power should be 0.0316 watts. For each antenna element, a complex noise n is generated based on the above noise power and superimposed on the original received signal s to obtain s+n. The noisy signal is then input into a 1-bit quantizer. Due to the randomization effect of the noise, the regularity of the quantization error is broken, and the plateau effect is mitigated.

[0128] In the embodiments of this specification, complex Gaussian white noise is added to the signals received by each antenna element based on the signal-to-noise ratio (SNR) of the signals received by each antenna element, resulting in signals received by each antenna element with added complex Gaussian white noise. This can utilize the randomness of the noise to break the deterministic periodic relationship between low-bit quantization error and the input signal, disperse the quantization sidelobe energy into a wide-angle noise substrate, and use the coherent gain of the large-scale array to compensate for the SNR loss, thereby further improving beam quality under low-bit conditions and overcoming the plateau effect at high SNR.

[0129] In one optional embodiment of this specification, the signals received by the antenna element include signals from multiple angles within the airspace; Step 110 includes: Based on beamforming weights, the signals received by each antenna element from multiple angles are weighted and synthesized to output the target antenna beams corresponding to each angle. Following step 110, the following is also included: The antenna radiation pattern of the target antenna array is formed based on the target antenna beams corresponding to signals at each angle.

[0130] Signals from multiple angles within the airspace are plane wave incident signals from different directions, used to test or evaluate the response of an antenna array to different incoming directions. For example, for each incoming angle (θ) k , φ kThe corresponding steering vector signals are generated respectively, and the output of the simulation array when receiving the plane wave in that direction is simulated.

[0131] Optionally, based on beamforming weights, one implementation method for weighted synthesis of signals received from multiple angles by each antenna element, outputting the target antenna beam corresponding to each angle, can be: keeping the weights fixed (corresponding to the target direction), sequentially changing the incident signal angle, and calculating the weighted synthesis output each time. Another implementation method can be: calculating the outputs at multiple angles in parallel to form complex radiation pattern data. This specification does not limit this approach in its embodiments.

[0132] Optionally, one way to form the antenna radiation pattern of the target antenna array based on the target antenna beams corresponding to the signals at each angle is to normalize the output power at each angle and plot it in polar or rectangular coordinates. Another way is to extract the peak value of the output amplitude and the sidelobe level, and plot the radiation pattern envelope. This specification does not limit this approach in the embodiments.

[0133] For example, suppose the target direction is θ0=0°, φ0=0°, and the weight is fixed as the conjugate of the steering vector in that direction. In the spatial domain, the incident angle θ is scanned from -90° to 90° in steps of 1°. A corresponding array signal is generated for each incident angle, and after low-bit quantization and weighted synthesis, the output power is recorded. After normalizing all output powers, a curve is plotted in decibels, yielding the radiation pattern of the antenna on a two-dimensional plane. From the radiation pattern, the main lobe width, the level of the first sidelobe, and the presence of quantized sidelobes can be read.

[0134] In the embodiments of this specification, based on beamforming weights, signals received by each antenna element from multiple angles are weighted and synthesized to output the target antenna beams corresponding to each angle. Based on the target antenna beams corresponding to each angle, an antenna radiation pattern of the target antenna array is formed. This can evaluate the beamforming performance of irregular arrays under low-bit quantization conditions, verify whether the quantization sidelobe suppression effect, main lobe width, and sidelobe level meet the design requirements, provide a basis for system parameter optimization, and can also be used for radiation pattern measurement in actual antenna testing.

[0135] Corresponding to the above method embodiments, this application also provides an antenna beamforming system, including an antenna array and a data processing module. The antenna array includes multiple antenna elements. The antenna array is obtained by shifting each antenna element in the initial antenna array based on a displacement factor. The displacement factor is determined based on the initial position information of each antenna element in the initial antenna array. An antenna array is used to receive an incident beam through each antenna element and obtain the signal received by each antenna element. The data processing module is used to form a target beam based on the signals received by each antenna element.

[0136] In this embodiment, the initial position information of each antenna element in the initial antenna array and the target direction information to be detected are obtained; based on the initial position information, the displacement factor corresponding to each antenna element is determined; based on the displacement factor, each antenna element is shifted to obtain the target antenna array; based on the target direction information, the steering vector of the target antenna array is determined, and the beamforming weight of each antenna element is calculated according to the steering vector; based on the beamforming weight, the signals received by each antenna element are weighted and synthesized to output the target antenna beam. This method can construct an irregular antenna array by shifting each antenna element through the displacement factor, so that the position of the antenna element can be adjusted according to its distance from the center of the array (the displacement factor of the center element is small and the displacement factor of the edge element is large), so that the quantization errors of each channel are incoherently superimposed during synthesis, thereby effectively suppressing the quantization sidelobes caused by low-bit quantization, while maintaining the main lobe gain and beam pointing accuracy. Furthermore, the irregular array obtained by shifting naturally has density taper characteristics, which enables the array itself to have sidelobe suppression capabilities. This simplifies or even eliminates the amplitude taper setting of complex weights in beamforming, reduces the computational complexity of beamforming weights, solves the problem that existing low-bit all-digital beamforming schemes cannot balance cost and beam quality, improves the engineering availability of antenna systems in harsh environments such as spaceborne and low-orbit constellations, and achieves the unity of low power consumption, low cost and high-quality beamforming.

[0137] Optionally, the data processing module includes a low-noise amplifier, a frequency converter, a variable gain amplifier, an analog-to-digital converter, and a beamforming unit; A low-noise amplifier is used to amplify the signal received by each antenna element to obtain the amplified signal corresponding to each antenna element. A frequency converter is used to convert the amplified signal corresponding to each antenna element to obtain the frequency-converted signal corresponding to each antenna element. A variable gain amplifier is used to adjust the amplitude of the frequency-converted signal corresponding to each antenna element to obtain the amplitude-adjusted signal corresponding to each antenna element. The analog-to-digital conversion unit is used to quantize the amplitude-adjusted signals corresponding to each antenna element to obtain the quantized signals corresponding to each antenna element. The beamforming unit is used to weight and synthesize the quantized signals corresponding to each antenna element to obtain the target beam.

[0138] Indicatively, Figure 22 A schematic diagram of an antenna beamforming system provided in an embodiment of this specification is shown. (Reference) Figure 22The antenna beamforming system includes multiple antenna elements for receiving incoming signals. Each antenna element is connected to a low-noise amplifier (LNA), and the output of each antenna element is connected to its corresponding LNA. The LNA amplifies the received weak signal with low noise, and its output is connected to the input of a frequency converter. The frequency converter down-converts the amplified RF signal to an intermediate frequency (IF) or baseband frequency, and its output is connected to the input of a variable gain amplifier (VGA). The VGA dynamically adjusts the signal amplitude according to the input range of the analog-to-digital converter (ADC), and its output is connected to the input of the ADC. The ADC uses low-bit quantization (e.g., 1-3 bits) to perform analog-to-digital conversion on the signals of each channel, outputting the quantized digital signal, and its output is connected to the input of the beamforming unit. The beamforming unit performs complex weighting on the quantized signals of each channel according to pre-calculated beamforming weights and sums them up to finally output the target beam. The entire system achieves low-power, high-quality digital beamforming of incoming signals through the cascading of low-noise amplifiers, frequency converters, variable gain amplifiers, low-bit analog-to-digital converters, and beamforming units.

[0139] In the embodiments described in this specification, the cascaded cooperation of a low-noise amplifier, a frequency converter, a variable gain amplifier, an analog-to-digital converter (ADC), and a beamforming unit enables the amplification, frequency conversion, amplitude adjustment, and low-bit quantization of the weak radio frequency signal received by the antenna unit. This signal is then weighted and synthesized using the corresponding weights of the irregular array, ultimately outputting a high-quality target beam. The ADC in this system employs low-bit quantization, combined with the non-coherent superposition characteristics of the irregular array on quantization errors. This effectively suppresses quantization sidelobes while maintaining low power consumption, achieving a balance between power consumption and performance in harsh environments such as spaceborne and low-Earth orbit constellations.

[0140] The above is a schematic scheme of an antenna beamforming system according to this embodiment. It should be noted that the technical solution of this system and the technical solution of the antenna beamforming method described above belong to the same concept. Details not described in detail in the system's technical solution can be found in the description of the technical solution of the antenna beamforming method described above. Furthermore, the components in the system embodiment should be understood as functional modules necessary to implement each step of the program flow or each step of the method; these functional modules are not actual functional divisions or separations. The system claims defined by such a set of functional modules should be understood as a functional module architecture that primarily implements the solution through the computer program described in the specification, and not as a physical system that primarily implements the solution through hardware.

[0141] Corresponding to the above method embodiments, this application also provides an antenna array, including multiple antenna elements and a controller, the controller being used to execute the above antenna beamforming method; In the antenna array, the physical position of each antenna element is obtained by shifting based on the initial position information and the displacement factor determined based on the initial position information. The controller is configured to calculate the beamforming weight based on the target direction information and perform weighted synthesis of the signals received by each antenna element to output the target antenna beam.

[0142] The above is a schematic scheme of an antenna array according to this embodiment. It should be noted that the technical solution of this antenna array belongs to the same concept as the technical solution of the antenna beamforming method described above. For details not described in detail in the technical solution of the antenna array, please refer to the description of the technical solution of the antenna beamforming method described above.

[0143] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0144] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that the embodiments in this specification are not limited to the described order of actions, because according to the embodiments in this specification, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in this specification are all preferred embodiments, and the actions, values, and modules involved are not necessarily essential to the embodiments in this specification.

[0145] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0146] The preferred embodiments disclosed above are merely illustrative of this specification. The optional embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the embodiments described herein. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the embodiments, thereby enabling those skilled in the art to better understand and utilize this specification. This specification is limited only by the claims and their full scope and equivalents.

Claims

1. A method for forming an antenna beam, characterized in that, include: Acquire the initial position information of each antenna element in the initial antenna array and the direction information of the target to be detected; Based on the initial position information, the displacement factor corresponding to each antenna element is determined; Based on the displacement factor, each of the antenna elements is shifted to obtain the target antenna array; Based on the target direction information, the steering vector of the target antenna array is determined, and the beamforming weight of each antenna element is calculated according to the steering vector; The signals received by each antenna element are weighted and synthesized based on the beamforming weights to output the target antenna beam.

2. The method according to claim 1, characterized in that, The target antenna array is pre-defined with physical and performance parameters; Before determining the displacement factor corresponding to each antenna element based on the initial position information, the method further includes: Based on the physical parameters and the performance parameters, the displacement parameters corresponding to the initial antenna array are determined; The step of determining the displacement factor corresponding to each antenna element based on the initial position information includes: Based on the initial position information, the polar radius of each antenna element is determined; Based on the polar diameter of each antenna element and the displacement parameters corresponding to the initial antenna array, the displacement factor corresponding to each antenna element is determined.

3. The method according to claim 1, characterized in that, The step of shifting each antenna element based on the displacement factor to obtain the target antenna array includes: Based on the displacement factor, the target position information corresponding to each antenna element is determined; Based on the target location information, each antenna element is shifted to obtain the target antenna array.

4. The method according to claim 1, characterized in that, After performing shift processing on each antenna element based on the displacement factor to obtain the target antenna array, the method further includes: The antenna elements in the target antenna array are rotated relative to each other to obtain the rotated target antenna array. The step of determining the steering vector of the target antenna array based on the target direction information, and calculating the beamforming weight of each antenna element according to the steering vector, includes: Based on the target direction information, the steering vector of the rotated target antenna array is determined, and the beamforming weight of each antenna element is calculated according to the steering vector.

5. The method according to claim 4, characterized in that, The step of rotating each antenna element in the target antenna array relative to each other to obtain the rotated target antenna array includes: Based on the position information of each antenna element in the target antenna array, the polar angle increment corresponding to each antenna element is determined; Based on the polar angle increment and the pre-constructed rotation function, each antenna element in the target antenna array is rotated to obtain the rotated target antenna array.

6. The method according to claim 4, characterized in that, After rotating the antenna elements in the target antenna array relative to each other to obtain the rotated target antenna array, the method further includes: Based on the preset antenna layout and beam scanning parameters, the rotated antenna array is trimmed to obtain the trimmed target antenna array. The step of determining the steering vector of the rotated target antenna array based on the target direction information, and calculating the beamforming weight of each antenna element according to the steering vector, includes: Based on the target direction information, the steering vector of the clipped target antenna array is determined, and the beamforming weight of each antenna element is calculated according to the steering vector.

7. The method according to claim 1, characterized in that, Before weighting and synthesizing the signals received by each antenna element based on the beamforming weights to output the target antenna beam, the method further includes: Based on the signal-to-noise ratio corresponding to the signal received by each antenna element, complex Gaussian white noise is added to the signal received by each antenna element to obtain the signal received by each antenna element with added complex Gaussian white noise. The step of weighting and synthesizing the signals received by each antenna element based on the beamforming weights to output the target antenna beam includes: The signals received by each antenna element with added complex white Gaussian noise are weighted and synthesized based on the beamforming weights to output the target antenna beam.

8. The method according to claim 1, characterized in that, The antenna unit receives signals from multiple angles within the airspace. The step of weighting and synthesizing the signals received by each antenna element based on the beamforming weights to output the target antenna beam includes: Based on the beamforming weights, the signals received by each of the antenna elements from multiple angles are weighted and synthesized to output the target antenna beams corresponding to each angle. After weighting and synthesizing the signals received by each antenna element based on the beamforming weights to output the target antenna beam, the method further includes: The antenna radiation pattern of the target antenna array is formed based on the target antenna beams corresponding to the signals at each angle.

9. An antenna beamforming system, characterized in that, It includes an antenna array and a data processing module. The antenna array includes multiple antenna elements. The antenna array is obtained by shifting each antenna element in the initial antenna array based on a displacement factor. The displacement factor is determined based on the initial position information of each antenna element in the initial antenna array. The antenna array is used to receive the incident beam through each antenna element and obtain the signal received by each antenna element; The data processing module is used to form a target beam based on the signals received by each antenna unit.

10. An antenna array, characterized in that, It includes multiple antenna elements and a controller, the controller being used to perform the antenna beamforming method as described in any one of claims 1 to 8; In the antenna array, the physical position of each antenna element is obtained by shifting based on initial position information and a displacement factor determined based on the initial position information. The controller is configured to calculate beamforming weights based on target direction information and to perform weighted synthesis of the signals received by each antenna element to output the target antenna beam.

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