数字化相控阵天线测试方法及测试系统设计

伴随着雷达技术的飞速发展,数字化相控阵天线开始广泛运用于各种相控阵雷达当中。由于数字化相控阵天线的工作原理与传统模拟相控阵天线差异极大,测试方法也发生了根本性的改变,原有的基于普通微波仪表的天线测试系统无法再对数字化相控阵天线进行测试,必须设计新型的数字化相控阵天线测试系统。本文首先介绍了数字化相控阵天线自身的工作原理和测试方法,随后提出了新型数字化相控阵天线测试系统的具体软硬件设计方案,实际应用表明数字化相控阵天线测试系统可以满足各种数字化相控阵天线的测试要求。     

基于互耦补偿策略的IFFT算法及其应用

介绍了一种基于互耦补偿矩阵(MCCM)的迭代快速傅里叶变换(IFFT)技术,并将其应用于宽角度扫描相控阵的低旁瓣综合中。首先,在所提出的综合方法中,将互耦补偿矩阵引入到IFFT技术中以考虑阵元间的互耦效应,使考虑互耦的阵列远场重新满足方向图乘积原理。然后,提出了一款基片集成波导背腔结构的宽波束天线单元,该天线能够同时激励起TE110与TE210两种模式从而展宽其工作频带且具有宽波束性能,并且基于此单元分别建立了阵元数为35,75,100的宽角度扫描相控阵天线。最后,利用所提出的IFFT技术对这三个相控阵进行低旁瓣综合。与基于有源单元方向图遗传算法的对比结果表明,在-60°到60°的扫描范围内均能实现低旁瓣电平,并且IFFT优化算法具有更快的速度。     

相控阵天线电磁发射特性的统计分析

相控阵天线波束指向高度动态变化,其电磁发射特性呈现出显著的统计规律,分析和测试所需的资源巨大。采用多项式混沌展开（PCE）探究二维平面相控阵天线发射特性的统计特性,根据方向图乘积定理等确定代表相控阵天线电磁发射特性的目标函数,利用PCE建立目标函数的等效代理模型。从理想点源构成的相控阵天线着手,分别考虑了主波束指向服从均匀分布和正态分布两种典型情况,通过计算机仿真模拟得到等效代理模型的概率密度函数和累积分布函数,并使用传统的蒙特卡罗方法结果作为参照来评估PCE方法的有效性和可靠性,最后对小型偶极子相控阵天线的波束指向服从两种典型分布的情况进行讨论。仿真对比结果表明,PCE方法在保证结果准确度的同时可以大大减少采样样本点数目,大幅提升相控阵天线电磁发射特性分析和测试的效率。     

基于宽波束磁电偶极子天线的宽角扫描线性相控阵列

设计并加工了两款基于宽波束磁电偶极子天线单元的宽角扫描线性阵列.首先,通过加载磁偶极子的方法拓展了天线单元的3-dB波束宽度.然后,基于该宽波束天线单元设计了两款具有良好宽角扫描特性的一维阵列天线.实测结果表明,天线单元的E面方向图3-dB波束宽度在9GHz—12 GHz均大于107°,H面方向图3-dB波束宽度在7GHz—12 GHz均大于178°.E面阵列中心单元的有源驻波比在9GHz—13 GHz小于2,相对阻抗带宽为36.36%.H面阵列中心单元的有源驻波比在9.6GHz—12.6 GHz小于2.5,相对阻抗带宽为27.03%.E面阵列在9GHz—12 GHz可实现±70°的有效宽角扫描.H面阵列在9GHz—GHz可实现±90°的有效宽角扫描.与传统的扫描阵列相比,设计的阵列可实现有效宽带宽角扫描,在X波段相控阵雷达方面具有广阔的应用前景.     

Design of a Compact Millimeter-Wave Microstrip Antenna with Wide Bandwidth and Broad Beamwidth

Design of a novel compact millimeter-wave microstrip antenna with wide bandwidth and broad beamwidth is presented. In the structure, multiple layers and a parasitic element as well as a coupling aperture are used to achieve wideband, while a conducting cylinder and the coupling aperture are used to obtain broad beamwidth. Finally, phased array with eight present elements has been designed as an example. Compared to traditional microstrip antennas and arrays, present antenna and array are of smaller dimension and broader beamwidth as well as wider bandwidth.     

光纤相控阵稀疏排布优化算法对比

光纤相控阵在激光合束、激光雷达等领域具有应用前景.光纤阵列配置方式不同于微波相控阵,光纤天线间距大于波长时存在周期旁瓣问题,影响主瓣能量分布.本文从物理模型出发,建立了基于同心圆环形点阵集合的光学相控阵天线布阵理论模型,提出了利用解析延拓的傅里叶变换方法实现干涉场强度的快速合成理论,讨论了在离散采样时数值仿真需关注的采样带宽和采样数目问题,解决了快速实现多光束干涉场数值仿真的问题.对比研究了两种优化光学相控阵天线配置的优化算法:遗传算法和粒子群算法,分别实现了不同种群数量遗传算法和粒子群算法迭代优化,分析了二者在优化过程中的收敛速度和优化效果,得到了峰值旁瓣比PSR=0.270的配置阵列.所提出的方法有望用于实际的光学相控阵天线配置中,指导天线主瓣能量最大化的优化设计;研究模型对不可微分目标函数优化问题的研究有一定参考价值.     

C/Ku波段共口径宽角度扫描相控阵天线

设计了一款具有高功率容量与宽角度扫描特性的C/Ku双频段共口径平面相控阵天线。在同一辐射口径内,相控阵天线包含有基于平面偶极子单元的C波段4×4阵列,以及基于混合零阶谐振贴片单元的Ku波段8×9阵列。所设计的相控阵天线的宽角度扫描性能归功于双频段阵元天线的宽波束辐射特性。下层混合零阶谐振贴片天线既能作为Ku波段的宽波束辐射单元,又能够为C波段的偶极子天线提供零反射相位,进而基于镜像原理拓宽偶极子天线的波束宽度。并且,对天线进行了介质埋入式设计,避免了空气击穿以提高天线系统功率容量。全波仿真结果表明,所提出的共口径相控阵天线在C和Ku双频段均实现了±45°的波束扫描,增益波动小于3 dB,天线阵列在各单元输入功率之和为1 W时功率容量达18.9 MW。     

A Novel Implementation Technique of Conical Scan Radar Using A Programmable Phased Array

In radar, planar phased array antenna plays vital role in electronic scanning in the azimuth and elevation direction to the horizon. In most operations using planar phased array both the coordinates of azimuth and elevation, are steered electronically. In this paper a conceptual schematic of a phased array antenna with programmable time delay units has been presented. It is shown that by suitably exploiting the time delay matrix one can have electronic beam rotation around the target axis as required in conical scan. Thus both the elevation and azimuth motors in conical scan system are replaced by electronic scanning. Heuristically, we have selected eight consecutive points for beam rotation in a polygon shape and can also be extended almost circular shape by increasing number of array elements and phase shifter (delays) in the delay matrix. The array requires dual control of phase gradient and individual phase values. The whole array is controlled by micro-controller. This presents exciting possibilities in radar operation.     

离子回旋波加热天线耦合的一种改进模型

讨论了离子回旋波在托卡马克中的电磁场分布.针对传统的天线耦合平板模型计算大孔径天线存在较大误差这一问题，提出了一种改进模型，使得计算精度有了很大提高.理论计算结果与实验观测更加符合. 关键词：     

Excitation of a Nonlinear Load Array on a Perfectly Conducting Shield Covered by a Dielectric

The problem of excitation of a nonlinear load array on a shield covered by a homogeneous dielectric layer is solved by the integral equation method in the case where this array is excited by a periodic source array. The influence of dielectric parameters on the radiation field of the proposed model of a nonlinear phased antenna array is studied numerically for the case where the array of filament-like external magnetic current is located on the shield and the layer surface.     

应用在相控阵雷达上的光学实时延迟线

相控阵天线是雷达技术的重要发展方向之一。电子相控阵雷达所遇到的问题是天线阵列孔径效应限制了雷达信号的瞬时带宽,使其不能满足通信和雷达技术的发展需要。光学实时延迟技术,可以解决这一问题。介绍了相控阵天线光实时延迟控制原理。并对几种典型的光实时延迟线的工作原理和技术特点作了简要的分析。     

相控阵天线主控系统中实时数据交互

波束控制系统是高功率相控阵天线的神经中枢,负责天线阵面中所有单元相位的精确控制和状态监测任务。为实现天线阵面的快速、精确波束转换,采用分布式拓扑结构和嵌入式实时操作系统,设计了两级分布式波束控制方案,开发了基于VxWorks的相控阵天线主控系统。通过UDP协议实现主控系统与其他系统的多节点网络通讯;针对高速、实时通讯需求,利用VxWorks多任务编程接口,设计了一种基于双缓冲队列的Socket通讯方法;为使通讯被各方正确解析,制定了自定义的应用层协议。基于VxWorks的相控阵天线主控系统的开发应用,验证了方案的可行性以及控制软件的可靠性和稳定性。     

基于FPGA的多轴直流电机控制系统

为了实现机械相控阵列天线的波束扫描,采用微型直流电机驱动螺旋天线单元转动来达到预定的辐射相位,研究了一种基于单片FPGA的多轴直流电机控制系统。采用IP设计思想,直流电机的位置控制用纯硬件逻辑电路的形式(直流电机控制IP核)实现,总线通信及轨迹计算由同一芯片上的微处理器(Nios II软核)软件实现,从而容易构建多轴直流电机控制的片上系统。利用Verilog硬件描述语言,设计了一种高性能直流电机控制IP核,并进行了仿真验证。为了验证该IP核的复用性,构建了一个56轴直流电机控制的片上系统。实验结果表明,此系统可对各个直流电机实现快速精确控制,每轴的运动相互独立,并且控制参数在线可编程,控制一致性满足系统设计要求。基于这种方式构建的系统,扩展方便、可移植性高、具有较好的适用性,已在某相控阵列天线中得到了应用。     

适用于隧道环境的二元相控阵天线系统

为了满足在隧道环境中实现高速率、高质量无线通信的迫切需求,研究了适用于隧道环境的高增益天线,提出了利用二元相控阵天线系统提高隧道内信号传输质量的新方法。相控阵天线系统由两个高增益天线单元及一个移相器组成,通过移相器调整其中一个天线单元的相位,使隧道内合成电场的最小值幅值达到最大,提升信号的平均场强。仿真结果表明:与单个天线发射信号相比,在3000 m隧道轴向传播范围内,相控阵天线系统发射信号合成电场的最低电平最少提升了19.6 dB;与两个天线同时发射信号相比,最低电平最少提升了12.4 dB,取得较好分集优化效果,消除多径效应导致的深度衰落,解决了隧道环境中存在的通信问题。     

圆柱类构件超声相控阵聚焦模型

在利用平面相控阵超声换能器对圆柱类构件检测时,受曲界面结构引起的入射波和回波时延的影响,扫描声束的波阵面产生弯曲,在利用传统迭代遍历算法计算延迟时间时效率低,无法发挥相控阵换能器检测优势。针对上述问题,建立了一种基于圆柱类构件特征和耦合介质特性的超声相控阵扫描成像的聚焦模型。该模型基于换能器、耦合介质、圆柱类构件材料特性和几何关系以及声线模型和折射定律,建立了耦合介质及被检构件的声速、曲面曲率半径、阵列与曲面间的距离等关联的延迟时间聚焦控制模型。利用该模型计算出的延时时间,对各阵元发射时间进行控制,从而实现扫描声束的聚焦。该文以液体和有机玻璃制介质楔块为例,对圆柱钢曲面的相控阵声束聚焦进行了仿真实验,结果表明该文方法计算效率显著提升,同时声束可以在预设位置实现聚焦,验证了该模型在计算效率上的优势与有效性。     

Focal-plane and aperture-plane heterodyne array receivers for millimeter-wave radioastronomy—A comparison

In this paper we consider the maximization of the throughput of a single large antenna, for two possible array configurations: focal plane imaging arrays and aperture plane phased arrays. We discuss trade-offs between the two types of array in terms of field of view, sampling efficiency and time to map, a source. We also discuss limits on the number of feed elements in an imaging array imposed by the deterioration in aperture efficiency off-axis.     

Tunable Chirped Fiber Grating Based Variable Time-Delay Network for Phased-Array Antenna Beamforming

In this paper, we present a photonics continuous beamforming system for optically controlled phased-array antenna based on a tunable fiber ring laser source and a novel variable true-time delay network consisting of one single-mode fiber delay line and four tunable chirped grating delay lines. The chirp rate of each chirped grating is tuned by bending a uniform fiber Bragg grating (FBG) bonded at a slant onto the lateral surface of a simply supported beam. This kind of variable true-time delay network can provide five-channel time-delayed signals that can be fed to an antenna array to achieve continuously beam scanning. The proposed true-time-delay unit with 5-element phased array steerer is suitable for phased-array antenna beamforming at frequencies up to 12 GHz.     

Design of Cylindrical Conformal Millimeter-Wave Microstrip Antennas with Broad Beamwidth

This paper describes the design of a novel cylindrical millimeter-wave microstrip antenna (MA) with broad beamwidth by means of isotropic transformation (IT). A planar millimeter-wave antenna with broad beamwidth is designed first, and then IT is used to design a conformal one based on the planar structure. In addition, phased array with eight present elements has been designed as an example. Finally, numerical results are given to show that the present antenna possesses broad beamwidth and its array is of large scanning angle, which also verify the validity of the method of IT.     

A 24-GHz Patch Array with a Power Amplifier/Low-Noise Amplifier MMIC

This paper presents an active patch array designed at 24 GHz. It can be used as a front-end component for a phased array. A series resonant array structure is chosen which is compact and easy excite. With 5 elements, the array proved a 12-dB antenna gain. A power amplifier and a low noise amplifier are designed on a single GaAs chip (PALNA). Bias switch is used in the PALNA, which greatly reduces the switch loss in a transceiver and increases the efficiency. 20-dB small signal gain is achieved in both power amplifier and low noise amplifier. The active patch array is built by the combination of the patch array and PALNA. The measured active gain of this antenna is 35-dB for the PA mode and 31-dB for the LNA mode. This active patch array can obtain an EIRP of 34 dBm with a total radiated power of 22dBm and a maximum PAE of 32%. To check the noise performance, we applied sources at both normal temperature and 77K (liquid nitrogen) and extracted the noise figure (3.5 dB) of the active antenna by the Y factor method. The results proved that the active antenna is working efficiently as both a transmitting and receiving antenna.     

X波段16单元矩形径向线螺旋阵列天线设计

研究了一种X波段16单元矩形径向线螺旋阵列天线。介绍了该矩形阵列天线的提出背景以及工作原理,分析了两种电磁耦合探针在X波段的耦合特性,开展了扼流结构与电磁耦合探针的协同设计,设计并数值模拟了中心频率为9.3 GHz的16单元矩形径向线螺旋阵列天线,并进行实验测试。测试结果表明:该口径为96 mm×96 mm的天线在中心频率9.3 GHz下,增益为19.51 dB,轴向轴比值1.05,驻波系数1.17。