基于高斯积分的平面波谱法分析天线罩电性能

将平面波谱表面积分法与高斯积分相结合分析天线罩的电特性。在计算了口径天线的差波谱以求解带罩天线差方向图的基础上,将高斯积分应用到由罩外表面切向场求远场方向图中,提高了平面波谱法的计算精度。最后通过具体算例表明了本文方法的有效性。     

机载雷达罩电讯设计中的AI-SI仿真技术

本文应用矢量口径积分和表面积分技术,给出了机载雷达罩波瓣特性的定量分析方法,在天线俯仰面尺度与波长相近及天线罩俯仰面曲率变化大的情况下,口径积分-表面积分方法比三维射线法更为精确,仿真计算结果与试验结果较为符合,证明了算法的有效性.     

基于方向图乘积的阵列天线口径反演

介绍了一种利用近场测量系统进行阵列天线口径反演的新方法。该方法将近场测量系统采集的近场数据变换到平面波谱（PWS）,在平面波谱上进行天线单元因子补偿后运用口径场反演算法,重构出被测阵列天线口径面上各天线单元馈电端口的幅相分布。随后使用计算机模拟的方法在理想近场数据上加入单元通道误差,将乘积反演方法与传统插值反演方法在模拟结果上进行对比,随后分析了单元不一致给反演结果带来的影响,证明了该方法具有较高的反演精度,有效提高了阵列天线口径校正的效率。     

平面波谱恢复算法在平面近场测量中的应用

介绍用于天线平面近场测量的一种近远场变换新算法。该法利用被测天线的平面波谱和口径场幅相分布之间的关系,以及天线口面的约束条件,用G-P迭代算法从平面波谱的置信谱域部分恢复出置信谱域外的平面波谱。这种方法减小了较小截断角下有限扫描面对测量精度的影响,并提高了天线近场测量的效率。     

带罩天线的口径积分-表面积分分析技术的改进

研究了带罩天线电磁辐射特性分析的口径积分-表面积分法，在罩外表面电磁流积分过程中，引入Gordon公式将罩面单元上的均匀相位分布修正为更贴近实际的线性分布，通过具体算例对改进方法的有效性进行了验证，计算结果表明，改进方法显著提高了带罩天线辐射方向图的计算效率和精度。     

口径积分法结合CST软件分析缝隙阵列天线罩

采用近场口径积分算法结合三维电磁仿真软件(Computer Simulation Technology,CST)仿真软件分析了带有多层介质天线罩的平板缝隙阵列.用CST对天线罩内的缝隙阵列天线进行仿真分析得到每个缝隙中心点的电磁场分布,对天线罩部分分析采用近场口径积分法分析天线罩部分对平板缝隙阵的影响.通过对该混合方法计算出的带罩平板缝隙阵列天线结果与CST全波仿真结果进行对比来验证该方法的正确性,结果表明:两者吻合很好.由于采用CST软件提取缝隙阵口径场考虑了阵元之间的互耦,较传统的理想阵元模型更加准确.混合方法避免了全波算法解决电大尺寸多层介质天线罩分析过程中耗费计算资源大、时间长的缺点.     

球面近场下相控阵天线口径诊断研究

在近场测量系统中,天线口径诊断是其中一项重要功能,它能够帮助天线设计师发现相控阵天线设计或者网络配置问题.平面近场中的口径诊断技术已经广泛地应用在雷达天线测试中,在球面近场测量中同样需要这种算法.本文基于球面坐标系下电磁场模式方法,得到球面近场条件下的口径反演算法.在仿真模型中计算得到了被测天线的口径场分布,计算结果与理论模型结果吻合.对X波段阵列天线进行了实际测试,得到了不同配置下的阵列天线口径反演结果,经过数据比对,证明了本文算法的幅度反演精度优于1 dB.     

面向远场计算的波谱射线方法

根据天线远区场对口径波谱的局部依赖特性,引入有效近场的概念,提出一种面向远场计算的波谱射线方法,该法采用波谱射线抽取的方法计算有效近场,通过近场空域积分计算远场,适合于具有雷达罩,透镜等近区散射体的天线远场计算。文中以带罩连续口径及阵列天线的远场方向计算为例,验证了方法的正确性和有效性。     

机载超宽带天线罩物理光学分析方法

该文提出了机载超宽带天线罩口径积分-表面积分-自适应网格(AI-SI-AG)分析方法。给出了用AI-SI-AG的计算和实测结果。理论分析和实验结果表明,该算法能够高效地预测定向和全向天线的带罩方向图,理论计算与实际测试符合较好,在工程应用中有较大的实用价值。     

带罩导弹远场方向图数值仿真中积分域的确定

导弹天线罩是用来保护位于高速飞行的导弹前端的天线系统免受外界影响的一种装置,为研究导弹天线罩对天线性能所造成的影响,该文在运用平面波谱-表面积分法分析天线罩综合电性能基础上,详细讨论了为获取带罩导弹远场辐射方向图所采用的数值算法中的积分区域的确定。     

New plane wave spectrum formulations for the near-fields of circular and strip apertures

The plane wave spectrum (PWS) method has previously been applied to analyze the near-field of planar apertures. The main goal of this paper is to present new PWS formulations for the near-fields of strip and circular apertures. Only special cases are developed in detail. For example, the uniform and parabolic aperture distributions are developed for the circular aperture. These new formulations are expressed in terms of either elementary functions or Fresnel integrals. Consequently, they permit considerably more rapid and efficient calculations than previous near-field formulations, by either the PWS or the aperture integration approach. The new formulations are especially advantageous for large circularly symmetric apertures (on the order of100lambdaand larger) in that computational efficiencies are improved by an order of magnitude or two over the original PWS formulation. The improvement over aperture integration techniques is more than a factor of 1000 for the100lambdaaperture.     

Comments on "New plane wave spectrum formulations for the near-fields of circular and strip apertures"

The above paper (see ibid., vol.24, p.438-449, July (1976)) applies a plane wave spectrum (PWS) formulation to diffraction problems involving circular and strip apertures and gives new results in terms of Fresnel integrals for the electric field near the aperture. In this note, a discussion of those new results is presented; conclusions are: As a technique for solving electromagnetic aperture diffraction problems, the particular PWS described gives inadequate results, especially for near-fields, and by using the standard Keller's formula, a geometrical theory of diffraction (GTD) solution for the diffracted field from a circular aperture is obtained, but the solution does not in general agree with the one given     

FDTD-PWS Scheme and Its Application to Analysis of Focusing Properties of Dielectric Lens

The focusing properties of lens are studied by a hybrid scheme that involves the finite-difference time-domain (FDTD) method for the aperture-plane field computation and the plane wave spectrum (PWS) method for the transformation from the aperture-plane field to the focal-plane field. To demonstrate the accuracy and efficiency of this new scheme, a Ka-band lens antenna is simulated and fabricated as an example. Subsequently, the near-field-region and the Fresnel-region fields of this lens antenna are measured by the planar-near-field (PNF) method. It is found that the results obtained by the FDTD-PWS scheme are in good agreement with the measured data. Furthermore, the numerical results and the computational requirements of this new scheme are compared with those of the near-field to near-field (NF-NF) transformation, the aperture integration (AI) method, the geometrical optics (GO)-physical optics (PO) method, and the full FDTD simulation. Both the central processing unit (CPU) time and memory requirement can be reduced efficiently. Finally, the effects of several fundamental issues, including spatial sample parameters, lens material, operating frequency, and designed focal length, on the accuracy of the proposed scheme and on the focusing properties of the lens are investigated.      

Near-field analysis by the plane-wave spectrum approach

Historically, most near-field analyses have relied upon aperture-integration techniques. The purpose of this paper is to point out the advantage of the plane-wave spectrum (PWS) approach for analysis of antenna near fields. The advantage of the PWS approach over aperture-integration techniques is quite substantial throughout the entire near-field region for circular apertures. Furthermore, the advantage increases in proportion to closeness to the aperture. The PWS approach also appears to offer advantage for noncircular apertures, e.g., rectangular, at least for large aperture sizes.     

Compact range reflector analysis using the plane wave spectrumapproach with an adjustable sampling rate

An improved method for determining the test zone field of compact range reflectors is presented. The plane wave spectrum (PWS) approach is used to obtain the test zone field from knowledge of the reflector aperture field distribution. The method is particularly well suited to the analysis of reflectors with a linearly serrated rim for reduced edge diffraction. Computation of the PWS of the reflector aperture field is facilitated by a closed-form expression for the Fourier transform of a polygonal window function. Inverse transformation in the test zone region is accomplished using a fast Fourier transform (FFT) algorithm with a properly adjusted sampling rate (which is a function of both the reflector size and the distance from the reflector). The method is validated by comparison with results obtained using surface current and aperture field integration techniques. The performance of several serrated reflectors is evaluated in order to observe the effects of edge diffraction on the test zone fields     

Plane wave spectrum-surface integration technique for radome analysis

The purpose of this paper is to report an accurate boresight analysis for practical three-dimensional antenna-radome systems. The analysis of practical three-dimensional antenna-radome combinations has been impractical for antenna aperture areas greater than about75lambda^{2}. The principal difficulty encountered is the excessive computation time required for the large number of antenna near field calculations. The key feature of the approach taken by the authors is the use of the plane wave spectrum (PWS) formulation for calculation of the antenna near fields. The PWS formulation provides much improved efficiency over other nearfield analyses and makes this analysis possible. The method can also be applied to analyze other antenna distortion.     

星载SAR功能结构一体化天线技术研究

提出了新型低剖面合成口径雷达(SAR)有源相控阵天线设计方法———多功能结构一体化天线技术,采用高密度互联、新型功能材料等进行模块化、轻量化的系统级集成设计,将系统功能与天线结构相结合,大幅减小了SAR天线的体积,增大了内部可用空间;同时,有效去除天线寄生质量及各分系统间的重复质量。对SAR天线进行了一体化设计验证,结果表明天线性能、结构承载及热控的指标满足要求,多功能结构一体化设计方法对大型有源相控阵天线系统的结构设计有实际指导意义。     

Theory and Applications of Infinitesimal Dipole Models for Computational Electromagnetics

The recently introduced quantum particle swarm optimization (QPSO) algorithm is employed to find infinitesimal dipole models (IDM) for antennas with known near-fields (measured or computed). The IDM can predict accurately both the near-fields and the far-fields of the antenna. A theory is developed to explain the mechanism behind the IDM using the multipole expansion method. The IDM obtained from single frequency solutions is extrapolated over a frequency range around the design frequency. The method is demonstrated by analyzing conducting- and dielectric-type antennas. A calibration procedure is proposed to systematically implement infinitesimal dipoles within existing method of moment (MoM) codes. The interaction of the IDM with passive and active objects is studied through several examples. The IDM proved to predict the interaction efficiently. A closed-form expression for the mutual admittance between similar or dissimilar antennas, with arbitrary orientations and/or locations, is derived using the reaction theorem     

发射天线罩抗微波烧毁理论分析

本文给出了机载宽带大功率发射天线抗烧毁理论分析方法和实验结果 ,从天线近场理论出发 ,计算了天线罩、极化器、密封膜片等处的功率密度。结合材料特性 ,给出了天线罩等的安全距离的计算公式 ,并提出了具体的抗微波烧毁措施。