Low-profile,low sidelobe array antenna with ultrawide beam coverage for UAV communication

This paper presents a design method to implement an antenna array characterized by ultra-wide beam coverage,low profile,and low Sidelobe Level(SLL)for the application of Unmanned Aerial Vehicle(UAV)air-to-ground communication.The array consists of ten broadside-radiating,ultrawide-beamwidth elements that are cascaded by a central-symmetry series-fed network with tapered currents following Dolph-Chebyshev distribution to provide low SLL.First,an innovative design of end-fire Huygens source antenna that is compatible with metal ground is presented.A low-profile,half-mode Microstrip Patch Antenna(MPA)is utilized to serve as the magnetic dipole and a monopole is utilized to serves as the electric dipole,constructing the compact,end-fire,grounded Huygens source antenna.Then,two opposite-oriented end-fire Huygens source antennas are seamlessly integrated into a single antenna element in the form of monopole-loaded MPA to accomplish the ultrawide,broadside-radiating beam.Particular consideration has been applied into the design of series-fed network as well as antenna element to compensate the adverse coupling effects between elements on the radiation performance.Experiment indicates an ultrawide Half-Power Beamwidth(HPBW)of 161°and a low SLL of-25 dB with a high gain of 12 d Bi under a single-layer configuration.The concurrent ultrawide beamwidth and low SLL make it particularly attractive for applications of UAV air-to-ground communication.

Shaped beam pattern synthesis with desired nulling level and minimum sidelobe level

For the anti-interference/denoise purpose,it usually requires minimizing the sidelobe level(SLL)of a wide-beam pattern with a desired low nulling level(NL)in the nulling region.To realize such an objective,the shaped-beam pattern synthesis(SBPS)is the most commonly used approach.However,since the SBPS problem focuses on synthesizing a predetermined beam shape,the minimum SLL via this approach cannot ensure to obtain the maximum power gain.Conversely,it cannot obtain the lowest SLL with a certain power gain requirement.Based on such consideration,this paper tries to further minimize SLL of a wide-beam pattern with a desired low NL nulling region,by solving the power gain pattern synthesis(PGPS)problem.The PGPS problem selects the array excitation by directly optimizing the power gain.Hence,it has the potential to reduce SLL,when achieving the equal mainlobe power gain constraint via SBPS.An iterative algorithm which converts the primal optimization problem into convex sub-problems is proposed,resulting in an effective problem-solving scheme.Numerical simulations demonstrate the proposed algorithm can obtain about 10-dB lower SLL than the existing algorithms.

Design of a low-sidelobe-level and wideband dielectric resonator antenna array for 60 GHz millimeter wave communication

A low-sidelobe-level( SLL) and wideband linear dielectric resonator antenna( DRA) array is proposed for 60 GHz millimeter wave communication. The array consists of 10 wideband DRAs which work at 60 GHz and it is fed by a Chebyshev feeding network to get a low SLL. To avoid the influence from the feeding network,a U-shaped substrate and a conformal ground are used,which can separate the DRA array and the feeding network. The parameter analysis and simulated results are presented.

Implementation of broadband low-sidelobe beamforming in time domain

In modern active and passive sonar systems, broadband beamforming for acoustic arrays is widely used to suppress unwanted interference and to detect target signals of interest. A broadband low sidelobe beamforming scheme in time domain is proposed in this paper. The first step of this scheme is to delay the outputs of each element in the acoustic array by a tapped-delay-line (TDL) to accomplish the integer part of the time delay need to form a beam. Then, finite impulse response (FIR) digital filters are used to implement the fractional part of the time delay. The weighting coefficients for all array elements at different frequencies to realize the low sidelobe beams are also implemented with the FIR digital filters. Finally, the outputs of the digital filters are summed up to yield the time domain beam output. The design of low sidelobe beam pattern and that of the FIR digital filters are two crucial technical issues in this beamforming procedure. The low sidelobe beams of each sub-band are designed using the optimized beam synthesis approach based on the principle of MVDR beamforming. An improved adaptive approach are used for the design of FIR digital filters, and the design requirements of these filters were specified by the weights of low sidelobe beams of each sub-band over the broad frequency band. Results of computer simulation for a twelve-element arc array show that the beamforming scheme is very effective in forming low sidelobe broadband beam.

Developing Three-Dimensional Beamshaping Techniques on Volumetric Random Arrays to Suppress Array Sidelobes

This paper proposes a three-dimensional (3-D) amplitude tapering technique on volumetric random arrays to minimize array sidelobes and emulate phased array operations on mobile platforms. Our ultimate goal is to realize wireless phased array applications carried out by mobile platforms;in this paper, we focus on the development of collaborative beamforming algorithms. This beamshaping technique mitigates the discontinuity of the current distribution along the array aperture and lower array sidelobe level (SLL) by specially paying attention to the array element’s depth deviation. In this work, step by step amplitude tapering procedures are clearly illustrated. Further, a reconfigurable phased array with sixteen patch antennas is tested to verify the fidelity of the 3-D beamshaping algorithm. Measured and simulated radiation patterns are benchmarked to evaluate the sidelobe suppression results, and the best sidelobe suppressed region is around the array’s main beam.

基于改进人工蜂鸟算法的稀布线阵优化

目的针对多约束稀布直线阵列存在旁瓣电平过大的问题,提出了一种基于改进人工蜂鸟算法的方向图综合方法。方法新算法通过分段式惯性权重动态调整转换概率来选择引导觅食和领土觅食方法,平衡算法的局部搜索和全局搜索能力;引入了柯西-高斯变异提升算法的抗停滞能力,使算法能够跳出局部最优,极大地提高了优化能力。结果新算法在给定阵列孔径、阵元数和最小阵元间距等约束下,实现了抑制阵列天线峰值旁瓣电平的稀布直线阵列综合优化。结论仿真结果表明,与传统方法相比,该方法能够在不同约束条件下得到更低的峰值旁瓣电平,新算法拥有更好的寻优能力和稳定性。最后对实际的阵列天线进行HFSS电磁仿真,并在仿真中得到了卓越的结果,进一步证明了所提方法的可行性。

基于无人机电力巡检的椭圆稀布阵列天线优化方法研究

为了提高电力巡检无人机的电磁检测性能,提出了一种基于无人机电力巡检的椭圆稀布阵列天线优化方法。阵列天线的阵列单元稀布排列,能够在保证阵列天线性能的同时,减少阵列单元的数目,从而减少馈电单元的数目。每个阵列单元等幅馈电,可以有效降低馈电网络设计的复杂程度,这些都能够在一定程度上降低阵列天线的功耗,提高无人机的巡检时间。利用改进智能优化算法,通过优化阵列单元的位置,使方向图的最高旁瓣电平(peak sidelobe level,PSLL)尽量低,因此文中设计的阵列天线具有较低的最高旁瓣电平,从而具有很好的环境抗干扰能力。仿真结果表明,在给定阵列单元数目、最小间距约束和阵列天线尺寸的情况下,提出的方法能够有效降低阵列天线方向图的最高旁瓣电平,对具有41个阵列单元的椭圆阵列天线进行优化,优化后的阵列天线方向图的最高旁瓣电平在-24dB以下。

基于改进型灰狼优化算法和窗函数加权的稀布矩形平面阵列天线综合

针对在阵列孔径、阵元数目、最小阵元间距等多约束条件下的稀布矩形平面阵列天线优化问题,提出了基于改进型灰狼优化(improved grey wolf optimizer,IGWO)算法和窗函数加权的稀布矩形平面阵列天线综合方法。首先,利用Tent混沌映射、非线性收敛因子、优势狼动态置信策略和对立学习策略对灰狼优化(grey wolf optimizer,GWO)算法进行改进,增加算法的种群多样性和跳出局部最优的能力。然后,利用窗函数对阵列单元进行加权,生成位置分布矩阵,减少稀疏矩阵优化时间,提高优化效率。最后,利用位置分布矩阵生成稀疏阵列,再运用IGWO算法进行多约束条件的稀布优化。为验证所提方法的有效性进行了仿真实验,实验结果表明,本文方法可以有效提高阵列天线的性能,降低峰值旁瓣电平,对于解决在多约束条件下的阵列分布问题,具有一定的工程意义和参考价值。

基于改进遗传算法的传声器随机阵列优化设计

针对传声器规则阵列因均匀采样间隔导致的空域混淆问题,提出一种基于改进遗传算法的传声器随机阵列优化设计方法。经过仿真分析,优化后24元随机阵列在保持主瓣性能的同时,有效抑制了旁瓣的增益。与均匀阵列相比,采用设计的遗传算法对阵列布局进行优化设计后可获得更好的旁瓣抑制和阵列增益。

改进爬行动物搜索算法的线阵波束形成研究

针对最小方差无畸变响应方法在已知先验信息的情况下抗干扰性能较差的问题,提出了基于改进爬行动物搜索的波束形成方向图控制算法。该算法通过设置合适的适应度函数,迭代寻找最优权值,并利用其实现对方向图的控制。首先采用Sobol序列对种群初始化方法进行改进,获得更均匀的种群初始分布;其次,改进进化因子提高该算法的收敛速度;最后,为了增强抗干扰性能,对适应度函数进行改进,使方向图旁瓣更低。仿真实验表明,相较于传统算法,该算法可以获得更深的零陷并将其准确的对准干扰来向,同时降低峰值旁瓣电平,提高了对干扰的抑制能力,使得元启发式算法在波束形成领域更具应用价值。

New Antenna Array Beamforming Techniques Based on Hybrid Convolution/Genetic Algorithm for 5G and Beyond Communications

Side lobe level reduction(SLL)of antenna arrays significantly enhances the signal-to-interference ratio and improves the quality of service(QOS)in recent and future wireless communication systems starting from 5G up to 7G.Furthermore,it improves the array gain and directivity,increasing the detection range and angular resolution of radar systems.This study proposes two highly efficient SLL reduction techniques.These techniques are based on the hybridization between either the single convolution or the double convolution algorithms and the genetic algorithm(GA)to develop the Conv/GA andDConv/GA,respectively.The convolution process determines the element’s excitations while the GA optimizes the element spacing.For M elements linear antenna array(LAA),the convolution of the excitation coefficients vector by itself provides a new vector of excitations of length N=(2M−1).This new vector is divided into three different sets of excitations including the odd excitations,even excitations,and middle excitations of lengths M,M−1,andM,respectively.When the same element spacing as the original LAA is used,it is noticed that the odd and even excitations provide a much lower SLL than that of the LAA but with amuch wider half-power beamwidth(HPBW).While the middle excitations give the same HPBWas the original LAA with a relatively higher SLL.Tomitigate the increased HPBWof the odd and even excitations,the element spacing is optimized using the GA.Thereby,the synthesized arrays have the same HPBW as the original LAA with a two-fold reduction in the SLL.Furthermore,for extreme SLL reduction,the DConv/GA is introduced.In this technique,the same procedure of the aforementioned Conv/GA technique is performed on the resultant even and odd excitation vectors.It provides a relatively wider HPBWthan the original LAA with about quad-fold reduction in the SLL.

非规则子阵阵列天线仿真与性能分析

文中设计了一种超宽带Vivaldi天线,并对其组成的16×16阵列按照划分设计的最优子阵方案进行仿真。通过均匀加权与低副瓣加权对天线阵列进行了波束偏转分析,从不同频点和偏转角度对波束扫描进行了分析,并仿真分析了天线的差波束及赋形波束,结果良好;同时对子阵级别的扰动进行了敏感度分析,发现在不同相位干扰下,干扰范围越大相位干扰对主瓣波束影响越大,主瓣增益降低和副瓣电平升高越明显,幅度干扰和幅相干扰也有同样结论。实际非规则子阵阵列天线在应用时,子阵级的相位误差在一定范围内对天线的影响不大,幅度误差对天线的整体影响也不大,即子阵级干扰对非规则子阵阵列天线扫描角度的影响不大,但对主波束的影响随干扰范围的增大而增大。本文的仿真分析可为非规则子阵阵列天线的设计和加工提供参考,丰富和拓展非规则子阵阵列天线设计仿真和性能分析领域,节省实际加工和应用的成本。

低旁瓣大扫描角多圆环光学相控阵优化设计

为了实现大角度低旁瓣的光束扫描,基于改进遗传算法和凸优化算法,对阵元位置以及阵元激励进行组合优化,设计了一种相邻阵元最小间距为18μm、工作波长为1550 nm的多圆环光学相控阵。优化过程分为两个步骤:首先对遗传算法进行改进,在特定俯仰角范围内优化环间距分布,从而在大扫描角范围内实现较低的峰值旁瓣电平;在此基础上,使用凸优化算法优化不同指向角下阵元的激励幅值分布,进一步降低峰值旁瓣电平。通过该组合优化,实现了俯仰方向为-45°~45°、水平方向为0°~360°的扫描范围,峰值旁瓣电平达到了-20.47 dB,最大远场发散角为0.146°。为验证算法的有效性,研制了含64个阵元的小规模多圆环光学相控阵,并搭建实验系统进行试验验证,实验结果与算法优化结果相符。

基于优化算法实现准N-bit智能超表面中低副瓣电平的设计

在相控阵天线阵列以及可重构智能超表面中,由于模拟的补偿相位难以实现,因此当前大多都采用数字量化相位的方式来实现补偿相位,但是要想实现更好的性能,需要每个单元上使用更多的二极管。分析并提出了一种准N-bit的设计方法,每个单元使用一个二极管来实现180°相位切换,并通过粒子群优化算法,优化单元预相位分布的位置,来实现接近精确补偿相位的副瓣性能。仿真结果表明,在10×10的阵列中,使用准3-bit的方案依然能够实现低于-10 dB的副瓣指标。

非均匀线阵遗传优化方案的比较研究

为使等幅边射直线阵具有尽可能低的最大副瓣电平 ,选择几种典型的选择算子和交叉算子组合构成遗传算法方案 ,进行遗传优化 ,并对 2 4种算法方案的优化效果作比较研究。结果表明 ,遗传算法方案设计的关键在于保持合适的种群多样性。如选用截断 +赌轮选择算子与均匀交叉算子组合的方案使 4 8单元边射直线阵的最大副瓣电平降低到- 2 6 .3d B。

基于脉冲串编码的MIMO雷达距离旁瓣抑制方法

MIMO雷达波形设计通常需要联合考虑空域时域特性,然而,在单脉冲发射波形设计中,在保证期望空域特性的情况下,往往存在时域旁瓣较高的问题。针对这个问题,该文提出一种基于脉冲串编码的时域旁瓣抑制方法。该方法采用空域发射方向图设计与时域波形设计分离的方式,通过对脉冲串的各子脉冲初相编码进行优化,可以在保证空域发射方向图不变的情况下,进一步抑制时域旁瓣。仿真结果表明,该方法可以有效地降低各多普勒通道的距离旁瓣。

球面阵列的阵元分布及副瓣特性分析

天线单元数目及位置是影响阵列天线辐射特性的两个重要参数。文章针对半球面,在满足口径及最小阵元间距的约束条件下,采用了一种新的建模方法对天线单元进行球面建模。仿真结果表明:通过与传统的建模方法比较,新模型可有效的避免主波束指向变化对旁瓣特性的影响,达到了令人满意的结果。

非均匀线天线阵优化布阵研究

针对有阵元数、孔径和最小阵元间距约束的稀布直线阵列综合问题,提出了一种基于修正遗传算法(MGA)的综合方法.该方法采用真值编码,个体的描述方式可使搜索空间减小,通过设计用于处理约束的矩阵变换和广义的交叉算子和变异算子,有效地避免了基因重组和变异时出现不可行解.在约束阵列孔径和阵元数的条件下,高效地实现了任意最小阵元间距约束下抑制峰值旁瓣电平(PSLL)的稀布阵综合.文中给出了修正遗传算法的流程,该算法的有效性和鲁棒性在稀布阵列综合的仿真实验中得到了验证.

阵列有源天线单元失效的影响与补偿

首先分析了阵列天线因单元（或单元群）失效引起的副瓣恶化和增益损失，然后用ＢＦＧＳ最优化算法对失效单元（或单元群）附近部分正常单元的幅相进行适当调整。结果表明，这种调整对由于单元失效引起的副瓣电平恶化有较好的补偿效果。

基于改进的粒子群算法的二维阵列天线方向图综合技术

该文运用一种改进的粒子群优化算法对不等幅激励的矩形平面阵列天线的最大旁瓣电平进行了优化,采用对全局最优粒子微扰和跳变的惯性权重策略,并使用粒子群算法本身对参数组合进行了优化选择。新算法大大改善了优化速度和收敛精度。对二维阵列天线旁瓣电平优化和稀疏阵列方向图综合的良好结果也证明了该方法的有效性。