互阻抗精度对实现天线极低副瓣的限制

实现极低副瓣阵列天线需要作精确的互耦补偿.如果阵列的互阻抗(或互耦系数)矩阵确知,理论上可以精确补偿互耦的影响,从而实现极低副瓣接收。但无论是计算还是测量得到的互阻抗矩阵都只有一定的精度,这个精度最终决定了补偿效果。本文研究了极低副瓣阵列天线中互耦补偿对互阻抗精度的要求;推导出了互阻抗误差与通道幅相误差的关系;进而得到了互阻抗误差与副瓣电平的关系。     

阵列天线互耦补偿技术研究

分析阵列天线的互耦机理,利用电磁散射理论研究阵列天线的散射特性,得到阵列天线的散射矩阵,并根据散射矩阵中的实际物理意义,将矩阵进行分解,推导出阵列天线的互耦补偿公式,避免了复杂的计算,并在实际测试数据的基础上,利用提出的算法进行互耦补偿,验证了该算法的有效性。     

相位加权阵列天线的互耦分析及补偿

采用分段正弦基函数Galerk in法计算了阵列天线的阻抗矩阵,利用互耦阻抗方程分析了相位加权阵列的幅相恶化程度,且用矩量法分析了互耦对两种相对加权阵列天线性能的影响。提出了一种互耦补偿的方法即网络分析法,仿真结果表明了这种补偿方法的正确性和有效性。     

互耦补偿后自适应阵列性能的分析

对互耦补偿后的自适应阵列性能作了深入的分析。分析表明,通过对互耦的补偿,自适应阵列能够完全抑制干扰,但是噪声的输出功率随着波束扫描方向的变化而发生变化,导致阵列输出信干噪比（SINR）性能下降。因此,互耦补偿后噪声是影响自适应阵列输出SINR性能的主要因素。仿真结果进一步验证了结论的正确性。     

互耦效应下端射阵机载雷达STAP方法研究

互耦效应是阵列天线一个固有的重要属性,而端射阵天线由于其特殊的主波束指向以及抑制栅瓣所要求的小阵元间距,其阵列间存在的互耦效应比侧射阵更加严重.本文首先分析了互耦效应对端射阵天线方向图的影响,构建了存在互耦效应下的天线方向图模型;然后给出了考虑互耦效应的杂波模型并分析了互耦对端射阵机载雷达杂波谱以及STAP（Space-Time Adaptive Processing）性能的影响;最后提出了一种基于杂波协方差矩阵重构的互耦效应补偿方法.计算机仿真验证了所提方法的有效性.     

阵列互耦对极化敏感阵列滤波性能的影响

在阵列互耦条件下,给出了极化敏感阵列接收信号模型;并在形式上把互耦误差分解为正交阵元接收因子误差和阵列接收因子误差,分别代表了阵列接收信号极化信息误差和空间信息误差.给出互耦条件下,信号、干扰空间匹配系数、极化匹配系数和最大SINR的数学表达式.在单干扰源情况下,分析了阵列互耦对极化敏感阵列滤波性能的影响.     

阵列天线互耦、阵元位置误差和通道不一致性的校正

研究了阵列天线中由各阵元互耦、位置误差及通道不一致性引起的阵列流形误差的校正问题.在计算得到互阻抗矩阵对互耦实行补偿的基础上,利用单信号源可以实现各阵元位置、通道幅度和相位的较精确的估计,从而估计出综合误差存在情况下的阵列流形.这种方法解决了一般条件和复杂情况下代价函数难于收敛的问题.仿真结果表明了这种校正方法的有效性和稳健性.     

非理想馈电端口下的共形阵完备互耦分析与校正

针对非理想馈电端口下共形阵列天线的互耦分析和校正问题,该文提出“结构模式互耦”和“天线模式互耦”的概念,其二者的叠加共同导致了共形阵列的完备互耦效应.论文基于全波数值分析和微波网络理论,提出了共形阵列完备互耦的分析和校正方法.最后,通过全波数值仿真分析了非理想匹配馈电下的12元柱面微带共形阵列天线,有效验证了完备互耦校正方法的有效性.     

超低副瓣偶极子相控阵互耦的研究＊

本文首次提出了从网络定义出发求偶极子阵列天线单元间互阻抗的方法,然后提出了用互阻抗矩阵来补偿单元间互耦的方法。计算结果表明:在扫描角不太大的情形下,用本文提出的互耦补偿方法是有效的。并在此基础上讨论了互耦对单元上电流分布规律的影响以及对副瓣电平的影响,为实现超低副瓣相控阵提供了详细的分析依据。     

秩损法互耦校正在GPS抗干扰中的应用

GPS空时联合(STAP)抗干扰技术是基于自适应波束形成的信号处理方法,通过干扰置零,能够对抗高功率的宽带和窄带干扰。理想的算法认为各个阵列天线之间互不影响,然而实际应用时,各个天线之间会产生互耦,严重影响系统性能。针对此,对自适应天线阵列及其互耦进行了建模,并采用秩损法进行互耦校正,最后将校正结果与分离迭代互耦校正算法作了对比。仿真结果表明,秩损法互耦校正不仅能够有效补偿系统因天线互耦损失的性能,而且在较高输入干噪比下其性能优于分离迭代算法。     

Compensating for the mutual coupling effect in a normal-mode helical antenna array for adaptive ing

A practical normal-mode helical antenna array together with a new method for the compensation of the mutual coupling effect is proposed for the efficient adaptive ing of interferences in a mobile communication environment. The helical antenna array is shown to be able to generate deeper s than an equivalent monopole antenna array in the presence of the mutual coupling effect. The helical antenna elements are smaller in size and less susceptible to the mutual coupling effect than monopole antenna elements. The new method for compensation of the mutual coupling effect is shown to have a greater ability and flexibility than previous methods. A new definition of mutual impedance is introduced and used to find the coupling-free signal voltages across the antenna terminal loads. Numerical examples demonstrate the superior performance of the proposed adaptive array and the new compensation method.     

THE LIMITATION OF MUTUAL IMPEDANCE PRECISION TO THE SIDELOBE LEVEL OF ARRAY ANTENNA

Accurate mutual coupling correction is necessary for an array antenna to reach ultra-low sidelobe level.If the mutual impedance or mutual coupling coefficient matrix of an array isperfectly known,theoretically,one can compensate the effects of mutual coupling completelyand realize the desired low sidelobe level.However,the mutual impedance matrix obtainedwhether by calculation or by measurement has limited precision,which limits the effectiveness ofcompensation.This paper deals with the requirements on the precision of mutual impedance forcompensation in ultra-low sidelobe array antennas.The relationship between mutual impedanceerrors and the amplitude and phase errors of an array is derived,by which the relationship betweenthe mutual impedance errors and the sidelobe level is obtained.     

Experimental study of mutual coupling compensation in smart antennaapplications

This paper investigates the benefit of mutual coupling compensation via a method of moments (MoM) approach in a uniform circular antenna array operating at 1.8 GHz. This mutual coupling compensation technique is applied to a direction of arrival (DOA) study of up to two cochannel mobile users. Field measurements and computer simulations are examined to explore the assumptions of the technique and verify its effect when using the Bartlett and MUSIC DOA algorithms. Computer simulations considering the application of the technique to down-link beamforming are also included. Experimental results show that the mutual coupling compensation technique improves up-link DOA algorithm performance primarily by reducing unwanted sidelobe levels. This reduction in sidelobe levels aids in down-link beamforming weight design. Specifically, simulation results show that use of the compensation technique allows DOA-based down-link beamforming algorithms to perform similarly to spatial signature-based algorithms. All field measurements were made using the smart antenna testbed at the University of Texas at Austin     

应用于交通信息检测雷达的阵列天线设计

介绍了一种应用于交通信息检测中多普勒雷达前端的K波段64阵元微带双天线,该天线采用并联形式馈电,通过对天线互耦的分析,电抗补偿和减小耦合等方面的改进,满足了天线性能和尺寸等实际应用的需求。双天线衬底背面固定集成雷达收发前端和中频信号处理电路。经过对天线和整个系统前端的测试表明:天线在工作频点,回波损耗低于-20dB,最大增益为25.2dB,E面、H面半功率波瓣宽度为8.1°和6.3°,其仿真和测试结果较好吻合。整个雷达前端在实际外场测试中检测准确灵敏,并在实际智能交通系统工程中得到了很好的应用。     

Accurate DOA estimation using array antenna with arbitrary geometry

The so called universal steering vector (USV) whose locus is equivalent to the array element pattern is applied to the direction of arrival (DOA) estimation by multiple signal classification (MUSIC) algorithm. It is shown that if the USV which includes the effect of the mutual coupling between the array elements is used, the compensation for the received voltage to remove the effect of the mutual coupling is not required any more. The USV for array antennas with arbitrary geometry is derived and evaluated efficiently by using the method of moments (MoM) so that the DOA estimation can be performed accurately by using the array antenna with arbitrary geometry. Numerical examples of the DOA estimation by a dipole array antenna, and an antenna array composed of a monopole antenna and a planar inverted-F antenna (PIFA) mounted on a mobile handset are presented to demonstrate the effectiveness of the proposed method.     

共享孔径交错稀疏阵列天线互耦误差建模与校正

共享孔径交错稀疏阵列天线是实现多功能阵列天线的有效途径。现有的参数化互耦消除方法都是针对均匀阵列天线展开的,其研究的互耦矩阵都是规则的方阵,对共享孔径交错稀疏阵列天线的互耦矩阵模型并不适用。在充分考虑共享孔径交错稀疏阵列天线中子阵内互耦的“稀疏”和“方位依赖”的特殊性后,通过将常规的互耦矩阵扩展表示为“非方”的“增广互耦矩阵”来对交错稀疏阵列天线子阵内和子阵间的耦合效应进行建模,并通过“增广互耦矩阵”的参数化估计最终实现了共享孔径交错稀疏阵列天线互耦误差的建模与校正。仿真结果证实了所提方法的有效性和可行性。     

多波束阵列天线单元互耦效应分析

互耦效应导致阵列天线单元间耦合能量的矢量和随扫描角而变化，在特定频率和方向上可能产生较大的功率反射，并且引起方向图出现虚假波瓣。运用散射参数法对阵列天线单元互耦效应进行理论分析。阐述了其对天线性能的影响，提出了各种指标的实验测试方法。