全空域多目标测控天线波束合成的频响特性

为了控制全空域多目标测控天线波束合成对全空域多目标系统设计的影响，研究了数字波束合成后的信号频响特性。通过分别对天线子阵以及所组成的球面阵进行数学建模，仿真得到相应波束的幅频特性、相频特性与群延迟特性，并分析了其变化原理。分析结果表明，全空域多目标测控天线波束合成频响特性与阵列流形、相控方式和扫描方式有关。研究结论可用于指导全空域多目标测控系统的设计。     

一种双极化多波束基站天线的研究

文章对双极化的水平面多波束基站天线进行研究,提出了一种新型的双极化宽波束复合辐射单元,并给出这种天线的仿真参数图,仿真结果表明,利用这种辐射单元在水平面组阵,可实现水平面宽角范围内的多波束双极化基站天线。     

基于微波光子的光学波束合成理论与仿真

光学波束合成技术是利用光信号作为载波携带射频信息而实现的一种新型的宽带射频波束合成技术,即用光信号来传输以及分配射频信号,实现射频信号的光波控制.文章介绍了基于微波光子的光学波束合成原理,重点介绍了光非相干和光相干波束合成架构,通过详细的理论公式推导以及软件仿真,表明上述两种光学波束合成架构可对多天线接收信号实现信号合成.针对目前大阵列天线单元系统对光学波束合成技术的迫切需求,利用光相干和非相干波束合成的各自优势,提出了一种适用于千量级天线阵列规模的光学波束合成架构,为光学波束合成技术在相控阵雷达、电子对抗等领域的应用提供解决方案.     

移动通信系统中基站天线波束赋形设计

摘 要：基站天线的波束赋形设计是提高移动通信系统信道性能的有效手段之一。本文基于移动通信系统，建立了基站天线赋形的优化模型，给出求解具有多个复杂约束条件的乘子罚函数的迭代算法。以八单元线阵为例，设计出压低上半空间所有副瓣峰值，填充下半空间零陷的基站天线，验证了本文方法的正确性和有效性。该方法对于波束赋形问题具有一定的借鉴意义。     

多波束小基站协作通信的资源分配和位置规划

针对小基站加载多波束阵列天线后协作提供通信覆盖的资源分配与位置规划问题,建立了以最小化基站总功耗以及基站间负载均衡为目标函数的多目标混合整数非凸优化模型;给出了一种迭代优化算法,将问题分为用户关联、功率分配和位置部署3个子问题,在固定基站位置和波束功率下通过改进的鲸鱼算法求解出用户与波束的关联关系,在此基础上利用连续凸逼近法和改进差分进化算法交替优化功率分配和基站位置部署。数值仿真表明,多波束小基站与所提迭代算法可灵活适应复杂业务需求分布,降低网络功耗和均衡基站间负载。可为小基站加载阵列天线增强通信覆盖提供参考。     

水平对数周期天线空域极化

针对水平极化对数周期天线圆阵波束合成,分析了地面上短波对数周期天线空域极化特性.根据接收天线理论,推导了新的阵列流行,阐明了水平对数周期天线圆阵的内在极化机理.依据新的阵列流行,理论和实验分析了现有采用相位加权的波束合成方法的性能.指出了对于水平对数周期天线圆阵波束合成时,需要采用相位极化联合加权,仿真结果表明联合加权方法可以有效改善波束合成的效果.     

高铁基于毫米波的自适应波束分合传输方案

向拥有较宽连续频谱的高频频段扩展带宽成为未来高铁无线通信系统提升容量的有力手段,不过,需要采用大规模天线波束赋形技术克服高频频段路径损耗严重的缺陷。在高铁双车载台方案中,可以通过大规模天线阵列形成双波束传输提高系统容量。在对其传输性能进行分析后发现,双波束传输优化配置与列车的位置有关。基于此,论文提出自适应波束分合传输方案,当列车距离基站较远时,为了避免波束间的严重干扰,双波束合成为一个波束来覆盖两个接收端,实现接收分集,提高接收信号质量;当列车距离基站较近时,分裂成双波束,实现空间复用,提高系统容量及传输可靠性。数值仿真结果表明,所提方案可以适应列车运行位置,提升传输性能。     

低副瓣任意波束直接合成算法研究

在传统阵列天线波束赋形设计中，通过对阵元天线辐射方向图进行幅度相位加权，获得阵列合成方向图.通常阵元激励幅度相位权值的获取，取决于优化算法对目标方向图和阵列合成方向图的对比，通过对阵元激励幅度相位进行大量随机选参后，获得优化结果.由于算法通常是基于相关的阵元方向图，且算法中缺乏副瓣抑制机制，使得方向图合成效率不高且副瓣效果通常不理想.该文设计了一种任意波束直接合成算法.该方法首先在阵元方向图的基础上获得一组互相独立的高增益窄波束（自由基波束），然后基于此波束进行方向图的直接合成，使波束赋形问题统一到基于自由基波束权值运算的范畴内，对波束赋形问题进行了统一，避免了未知参量的随机优选过程，极大提升了阵列天线波束赋形设计的效率.同时在自由基设计的过程中结合了副瓣抑制机制，且这种副瓣抑制机制与波束赋形过程互相独立，使合成波束的副瓣天然地具备了低副瓣的特征.     

全息通感一体化：高能效的波束赋形设计

通信感知一体化是解决频谱拥塞问题的重要手段。现有的通感一体化系统依赖高功耗的相控阵，限制了其在功率受限场景中的应用。作为一种低功耗天线，可重构全息超表面可以用于替代相控阵，从而形成全息通感一体化这一新范式。在该范式中，利用可重构全息超表面作为发射天线，可以同时实现高空间自由度与低功耗，进而提升通感一体化系统的整体性能。研究了全息通感一体化系统的能效，通过联合设计基站和全息超表面的波束赋形提升系统能效。然而，由于基站的数字波束赋形和可重构全息超表面的模拟波束赋形相互耦合，使得波束赋形的联合设计具有挑战性。为了应对这一挑战，首先构建了最大化能量效率的优化问题，并提出了全息波束赋形优化算法来解决这一问题。仿真结果显示，与传统基于相控阵的通感一体化系统相比，全息通感一体化系统可以在相同发射功率和天线尺寸的条件下实现更高的能效。     

传统基站到有源天线基站的演进

随着无线网络的发展,基站架构也不断演进。详细介绍了传统基站、分布式基站、有源天线基站的架构,对比了其优缺点,说明了演进到有源天线基站的必然性。针对有源天线,明晰其概念,给出了设计思路,探讨了其技术优势。有源天线可通过波束成形覆盖更多小区,完全可满足未来低能耗、低成本绿色移动通信系统的发展要求,将成为基站演进的必然趋势。     

Efficient multibeam synthesis with interference ing for large arrays

This paper describes a class of multibeam synthesis algorithms that are useful for large arrays when simultaneous ing of interference is required. In these algorithms, the computational cost is kept small by using fast Fourier transform (FFT) beamforming, while at the same time interference is ed using spatial projections. Once the interference steering vectors are determined, these algorithms have a computational cost per output which is only slightly greater than that of the FFT with no interference ing. In addition, techniques are derived that allow the Fourier beams to be protected against distortion by constraining the patterns, reducing the pattern variation, or both. These techniques may be particularly well suited for some new radiotelescopes now in the planning stages.     

高分辨多波束海底地形探测的MSB-RMU算法研究

常规多波束测深系统中采用的FT波束形成技术不能完成外侧波束区域海底地形的高精度估计,而采用相位检测法的相干多波束测深系统在此区域能得到高精度和高分辨地形估计。基于此,该文提出MSB-RMU算法,此算法结合FT波束形成技术和相位检测法的优势,具有较高的空间分辨率,能够同时实现中央波束区域和外侧波束区域的高精度地形估计。对试验数据的处理结果表明此方法的有效性、实用性与优越性。此算法保证了国内首台多波束测深系统能够达到6倍水深以上的覆盖扇面。     

Beamforming network on the basis of unequal coupled waveguides

The theory and the results of the numerical simulation of a microwave beamforming network in the form of a system of unequal coupled waveguides are presented. The beamforming network is designed for a quasi-optical multibeam antenna. It is shown that the proposed N-channel network forms N flat-top patterns, which intersect each other at a level close to ?3 dB. The input channels are matched and are isolated. The theory of coupled waves is used to optimize the device. The theory of the systems of coupled EBG waveguides is developed on the basis of the method of compensating sources. The design version of a beamforming network on the basis of coupled EBG waveguides is considered. The results of the numerical calculation of the characteristics of this beamforming network are presented.     

A high-speed adaptive antenna array with simultaneous multibeam-forming capability

A new type of adaptive beamforming antenna system architecture is proposed for multichannel wireless communications. Multibeam communication with high data throughput is accomplished using the proposed beamformer architecture. The system consists of analog mixers, a multitone direct digital synthesizer (DDS), and a digital signal processor (DSP) controller. The essential idea of multibeam forming is based on a multitone weighting scheme combined with analog-digital hybrid signal processing. While the real-time multibeam construction is realized by the analog mixer circuits and a DDS, the complicated adaptive beamforming and direction-of-arrival estimation algorithms are carried out by the DSP. In this architecture, only one beamformer circuit is required to handle multiple beams, leading to significant reduction in hardware counts. A 5.8-GHz eight-element adaptive beamforming array successfully demonstrates two-beam simultaneous beamforming with less than three degrees of peak and steering errors and more than 20-dB interference suppression. The test-bed exhibits successful two-channel data recovery at 25-Mb/s data throughput in each channel with binary phase-shift keying modulation, for simultaneous dual-beam reception. The bit-error-rate measurement validates the robustness of the communication quality under strong interferences.     

Fast Iterative Method of Power Synthesis for Antenna Arrays

A fast and simple method of power synthesis for antenna arrays of arbitrary geometry is presented. The method adopts an auxiliary function having the desired amplitude pattern and a generic phase pattern, and determines in closed form the array pattern approximating the auxiliary function in both amplitude and phase. A cost function involving the auxiliary function and the approximating pattern is minimized by modifying the phase pattern of the auxiliary function, using a simple and fast iterative technique. Once the optimal phase pattern has been found, the array pattern approximating the corresponding auxiliary function is the synthesized pattern. The proposed method allows to satisfy stringent requirements on the amplitude pattern, including multibeam synthesis and radiation suppression within large angular regions. Numerical results show the effectiveness of the algorithm and are compared to those obtained using other existing methods. In order to achieve a more significant comparison such methods have been properly modified to improve their performances. Such comparison shows that the presented algorithm allows a significant reduction of CPU time with respect to the other considered methods, as well as a weaker dependence on the starting point. Finally, the presented method is extended in such a way as to reduce the dynamic range ratio (DRR) of the array excitations.      

一种星载阵列天线的高效波束赋形算法

随着有源相控阵和数字波束形成技术的应用, 低轨道卫星通信多波束阵列天线不仅可以形成同时多个固定的对地等通量低旁瓣赋形波束, 还具备了可以随着通信任务需求变化, 动态调整方向图形状的能力.但是目前常用的高性能波束赋形算法, 运算量较大, 收敛速度慢, 优化参数调整复杂, 无法直接应用于在线实时计算.针对上述要求, 提出了一种高效的迭代最小方差方向图综合方法.该方法采用方向图分区域加权逼近和方向图相位去约束技术, 在满足较高的主瓣赋形精度和旁瓣电平控制等指标要求的前提下, 具有迭代过程简单、优化参数少、算法稳健和运算量少等特点, 可以部分满足要求波束方向图动态变化的卫星通信系统权重系数在线计算的需要.     

Beamforming experiment with a DBF multibeam antenna in a mobilesatellite environment

This paper describes a digital beamforming (DBF) multibeam antenna that incorporates a compact digital signal processor (DSP) engine, and the results of using it in a beamforming experiment receiving a satellite signal in a land-mobile environment. A considerable reduction in the scale of the DSP engine has been achieved by using field programmable gate arrays (FPGAs). To capture a satellite signal arriving from an unknown direction, a two-dimensional (2-D) spatial FFT signal processing provides orthogonal multibeam patterns on the broad side of a planar array antenna. The experimental results demonstrated the features of coarse acquisition and tracking of a signal arrival by selecting the strongest of the beams without assistance from direction finding sensors or microwave phase shifters. The DBF multibeam antenna will provide high-quality communications and increase traffic capacity if it is applied to high-gain mobile antennas or multispot-beam base station antennas in cellular or satellite mobile communications     

Intelligent antenna solutions for UMTS: algorithms and simulation results

This article outlines the development of intelligent antenna (IA) solutions for UMTS, a third-generation W-CDMA system. Since the selection of an antenna configuration paired with realizable uplink/downlink algorithms that can satisfy all operating environments is a broad task, this article focus is on cost-effective antenna arrays for macrocells. Algorithms that exploit the antenna configurations and act at both the physical and MAC layers are highlighted and supported by simulation results. Two solutions stand out for UMTS: a universal beamforming algorithm that unifies user-specific and fixed beamforming under one framework, and multibeam scheduling (MBS) that significantly increases downlink packet data throughput using the concept of code reuse in conjunction with beamforming. The article summarizes the critical issues that were faced in the development of an IA solution capable of delivering the theoretically promised benefits to end users.     

高精度多功能自适应相控阵天线的研究

从发掘相控阵天线潜力使其具有高精度、抗干扰和多功能等角度出发,对下列课题进行了研究：适当随机相位量化优化波束指向的算法;适当相位加权和振幅加权波瓣置零实数算法;适当相位加权和振幅加权的ＤＢＦ实数算法;随机对角线加载算法对自适应算法的影响;新的线性调频信号检测和估计方法;非对称波瓣算法。以上算法均采用了适当改变技术（ＡＣＴ）。计算机模拟结果证明,这些算法是行之有效的。     

基于菲涅尔区修正结构的多波束自适应天线

菲涅尔区相位修正结构具有类似于二次曲面的聚焦特性和更好的偏轴扫描特性,将该结构与馈源阵列相组合,并通过用改进的ＬＭＳ算法对馈源阵列输出的自适应信号处理,实现了对来波方向的估计和数字波束形成,从而构成了一类新型的多波束自适应天线。计算机模拟的有关结果证实了其可行性。