并行FDTD-UTD方法分析机载相控阵天线

利用时域有限差分法(FDTD)-UTD(一致性几何绕射理论)混和算法分析机载相控阵天线的辐射方向图.将复矢量场作为FDTD方法和UTD方法的接口,提出FDTD-UTD混和算法解决机载相控阵天线辐射问题.首先利用并行FDTD方法通过全波分析得到精确的相控阵的辐射复矢量场,然后将此结果作为源代入UTD算法来预测相控阵受机体的影响.结果表明该方法可以有效地解决机裁相控阵辐射分析问题.     

利用PO修正MM-UTD计算机载波导缝隙天线阵的方向图

针对物理光学方法(PO)中Ludwig算法数值发散的问题,提出了解决方案.以复矢量场为接口,利用PO修正了MOM.UTD算法,并应用于机载波导缝隙天线阵方向图的计算.采用MOM分析天线自身的特性,UTD分析飞机形状简单的大型部件对天线方向图畸变的影响,PO分析机头等形状复杂的部件的影响.计算结果表明,此3种方法的结合算法适用于计算靠近机头的机载天线的方向图.     

UTD结合MM计算复杂环境中天线的方向图

一致性几何绕射理论(UTD)算法中,天线被等效为一个源点;UTD方法需要根据天线的指向,得到反射点(绕射点)处的入射场,从而得到场点处的反射场(绕射场).然而,对于某些形状复杂的大型天线(比如八木天线),将天线中任何一点作为天线的源点都不合适,将任何一个方向作为天线的指向也都不合适.因此,可用矩量法(MM)计算天线的电流,每一小段电流等效为一个电流元,中心点等效为UTD算法中的源点.这样,该电流元在反射点(绕射点)的辐射场就很容易得到.将此辐射场作为UTD的入射场,就可以计算每个电流元在场点处的场.所有场点的场叠加、归一,即可得到天线的方向图.     

机载天线辐射方向图的MoM-UTD混合法分析

采用矩量法(MoM)结合一致性几何绕射理论(UTD)的混合方法分析了机载单极天线的辐射特性。用该混合方法建立的机载天线辐射模型更符合实际,并且它同时具有MoM的精确性和UTD的高效性,克服了单一方法的不足。计算结果对于预测天线间的电磁兼容性和优化天线布局具有一定的指导意义。     

并行UTD算法及在机载天线分析中的应用

要实现对复杂环境的EMC分析,最大的障碍是计算量过大,耗时太长.本文提出MPI结合UTD的并行算法,实现了大型复杂飞行器机载天线的方向图特性分析.数值结果表明,并行UTD算法可以大大节省计算时间.这一方法为在小型机系统下实现大型EMC分析软件提供了坚实的基础.     

有源相控阵天线快速检测系统设计

机载电子战系统有源相控阵天线的完整参数检测方法步骤复杂且消耗时间较长,文中基于有源相控阵天线波束捷变特性设计出新的天线检测方法,可实现有源相控阵天线检测过程自动化,从而大幅提高天线全波位、多频点方向图参数测量速度,并使用改进的灰色关联度数据分析算法(GRA),对测量所得的参数集进行快速计算与故障原因分析。为机载电子战系统有源相控阵天线的研制、开发、检测提供了技术支持。     

机载天线辐射方向图的MM—UTD混合法分析

采用矩量法（MM）结合二致性几何绕射理论（UTD）的混合方法计算了机载单极天线的辐射方向图。该混合方法建立的机载天线辐射模型更符合实际，并且它同时具有MM的精确性和UTD的高效率，克服了单一方法的不足。计算结果对于预测天线间的电磁兼容性和优化天线布局具有一定的指导意义。     

用MoM-UTD混合方法分析机载平台天线间的隔离度

天线间的隔离度是机载平台电磁兼容(EMC)的重要指标之一。由于机载平台的电尺寸很大,因此单纯矩量法(MoM)很难解决。一致性几何绕射理论(UTD)虽是高频方法,适合解决电大问题,但其精度较低。该文采用MoM-UTD混合方法分析机载平台天线间的隔离度,兼顾了计算精度和速度,得到的计算结果和测量值吻合良好。     

机载有源相控阵天线阵的可靠性研究

天线的超低副瓣特性是影响机载相控阵雷达下视能力的一个重要指标。在传统的机载相控阵雷达天线的可靠性设计中是采用对n中取k的表决模型,该方法没有考虑失效T／R组件在天线阵列中所处的物理位置对于天线副瓣性能的影响。通过仿真分析,提出了一种计算有源相控阵雷达天线阵可靠性的新模型,该模型统筹考虑了失效组件的物理位置因素的影响并归纳出新的计算公式,并在此基础上举例说明。该可靠性新模型可用来指导机载相控阵天线的可靠性预计、分配和设计。     

相控阵天线系统散射分析

该文采用S参数分析了有源相控阵天线单元馈电系统模型的接收机负载反射系数.将该反射系数代入阵列天线散射场基础理论公式分析了有源相控阵天线的散射场,将有源相控阵天线的天线模式项散射场分为天线模式反射散射场和天线模式相控散射场进行分析.最后通过一维线阵验证了理论分析结果.该分析方法和分析结果为相控阵天线RCS计算和控制提供了理论指导.     

A DFT-based UTD ray analysis of large finite phased arrays on a grounded substrate

A discrete Fourier transform (DFT)-based asymptotic high-frequency, uniform geometrical theory of diffraction (UTD) ray solution is developed to describe, in closed form, the collective field produced by large finite phased arrays of printed antenna elements on a grounded material substrate. Such a DFT-UTD ray analysis yields useful physical insights into the large array radiation and scattering mechanisms. This is in contrast to the conventional array element-by-element summation for the radiated field which lacks the above useful properties. In the present work, any realistic arbitrary array current distribution, i.e., in the presence of array mutual coupling, is represented by a DFT expansion so that each term in the expansion becomes a simple uniform array distribution with a linear phase, which then directly facilitates the development of the asymptotic UTD ray solution. Furthermore, another significant advantage of the DFT is that for most practical array excitations, only a relatively few DFT terms remain dominant in the expansion and are sufficient to provide reasonably accurate results. Some numerical examples are presented to illustrate the utility of this collective DFT-based asymptotic UTD ray solution for large array fields.     

机载相控阵天线辐射方向图的分析

采用一致性几何绕射理论分析了某型预警机机体对其上安装的大型相控阵天线辐射方向图的影响，计算了天线经机体散射后的场，优化了大型相控阵天线安装的最佳位置，为天线装机后辐射性能预测与布局优化提供了理论依据。     

On the radial component of the electric field for a monopole phasedarray antenna focused in the near zone

The near-zone radial and principal spherical components of the electric field for a linear phased array antenna that is focused at one to two aperture diameters in the near zone are investigated. The phased array antenna consists of thin monopole elements, which are analyzed by using the method of moments. A theoretical formulation is described and computer simulation results are presented. The results show that the radial component is negligible in the focused near-field region, which allows the principal component to be accurately computed from knowledge of only the tangential electric field on the focal plane     

超声相控阵输出声场优化及仿真

为使超声相控阵在输出平面上的声压输出达到较好的分布模式,本研究通过预先设定相控阵输出面上的声压分布形态,然后利用迭代算法来求解超声相控阵驱动向量,最终实现了超声相控阵在输出平面上声压输出的有效控制,并通过计算机仿真对这种算法进行了验证。     

NUMERICAL SIMULATION OF ANNULAR PHASED ARRAY OF DIPOLE ANTENNAS USING THE FD-TD METHOD

The problem for calculating near fields of EM radiation systems by using the finitedifference time domain(FD-TD)method are discussed and the annular phased array of dipoleantennas has been simulated numerically by use of the FD-TD method.For a test run thenear field and current distribution of the single dipole antenna are calculated.The near fieldsof the annular phased array of dipole antennas in central region filled with deionized water arecomputed and the interaction of near fields with an anatomically-based inhomogeneous model ofhuman torso is considered as well.     

Phased array antenna analysis with the hybrid finite element method

A new analysis technique for infinite phased array antennas was developed and demonstrated. It consists of the finite element method (FEM) in combination with integral equation radiation conditions and a novel periodic boundary condition for 3-D FEM grids. Accurate modeling of rectangular, circular and circular-coaxial feeds is accomplished by enforcing continuity between the FEM solution and several waveguide modes across an aperture in the array's ground plane. The radiation condition above the array is enforced by a periodic integral equation in the form of a Floquet mode summation, thus reducing the solution to that of a single array unit cell. The periodic boundary condition at unit cell side walls is enforced through a matrix transformation. That mathematically “folds” opposing side walls onto each other with a phase shift appropriate to the array lattice and scan angle. The unit cell electric field is expanded in vector finite elements. Galerkin's method is used to cast the problem as a matrix equation, which is solved by the conjugate gradient method. A general-purpose computer code was developed and validated for cases of open-ended waveguides, microstrip patches, clad monopoles and printed flared notches, showing that the analysis method is accurate and versatile     

大口面相控阵天线的机体散射效应

本文利用一致性几何绕射理论（ＵＴＤ）对装机后大口面相控阵天线辐射方向图的预测进行几何建模,研究并提出了适合该问题的点源模型和叠加模型,分析了天线受机体散射影响后性能的变化,为天线装机后辐射性能预测与布局优化提供了理论依据。     

基于近场测试的相控阵天线自动化校准 与阵面监测方法

相控阵天线装配好之后,由于各组成部件机械加工误差、装配误差、部件老化更换和环境温度改变等因素,各 单元通道的初始幅相产生差异,因此必须对天线的所有系统进行校准。本文针对小型化相控阵平台,通过硬连接将相控 阵天线的波控系统与测试设备相结合,提出一种简便的自动化近场逐点校准方法。同时,本文还提出一种简单的外监测 方法。当相控阵天线工作期间,可对阵面的幅相分布进行监测。可在相控阵天线工作期间,对近场幅相校准数据进行修 正,达到阵面自身校准的目的。经对一个16阵元的相控阵天线进行实验测量可知,该自动化校准与阵面自身校准方法可 以准确、快捷测试出天线阵面的幅相分布。非常适合一维、二维相控阵天线,尤其是小型化相控阵天线的幅相校准与监 测。