带平台多阶振幅量化的低副瓣口径分布

本文提出了一种带平台多阶振幅量化的低副瓣口径设计方法并论述了其分析方法和计算公式,给出了本文算法与作者(1993)提出的多阶振幅量化方法在峰值副瓣电平、口径效率、归一化输入功率以及具有容差情况下的副瓣恶化等的计算比较结果。结果表明,在相同的条件下,本文提出的方法优于多阶振幅量化方法。     

机载固态有源相控阵指数约束二维可分离的多阶振幅量化低副瓣口径综合

本文提出了一种用于机载有源阵相控阵具有指数约束的二维可分离多阶振幅量化低副瓣口径设计技术，它能有效地降低水平面和非主平面的峰值副瓣电平并能减少Ｔ／Ｒ组件的品种数。采用二维可分离的设计思想，在工程应用中可大大地减少列馈网络的品种数。计算机仿真计算结果证明了本文的理论分析     

机载固态有源相控阵指数约束二维可分离的多阶振幅量化低副瓣口径综合

本文提出了一种用于机载有源相控阵具有指数约束的二维可分离多阶振幅量化低副瓣口径设计技术，它能有效地降低水平面和非主平面的峰值副瓣电平并能减少Ｔ／Ｒ组件的品种数，采用二维可分离的设计思想，在工程应用中可大大地减少列馈网络的品种数，计算机仿真计算结果证明了本文的理论分析。     

基于泰勒分布线阵特殊旁瓣技术的研究

提出了基于泰勒加权分布线阵特殊旁瓣要求的设计方法,其波束图是由给定的旁瓣级要求来设计的泰勒分布波束图,在实际需要的特殊旁瓣要求上,设计满足了要求的最窄波束宽度波束图。给出了相应的参数设计,并证明该设计能在要求的最大旁瓣级上获得最大阵增益。借助计算机对线阵进行波束图设计。结果表明,使用该方法设计的波束图能满足特殊旁瓣要求和最大阵增益。     

任意阵列的低副瓣宽凹口仅振幅加权口面综合的实数算法

本文给出了一种仅振幅加权的宽凹口低副瓣的口面综合的实数算法,它基于“单元零点向量法”和Ｇｒａｍ—Ｓｃｈｍｉｄｔ正交化方法,此算法能够适用于任意复杂口径天线阵列（包括一维、二维和三维情况）。作为举例,本文给出了此算法对线阵、圆周阵和椭圆周阵的模拟计算结果,结果证明了本算法是行之有效的。     

用有一定电阻的双曲面设计低旁瓣卡塞格伦天线

本文用沿径向有阶梯变化的表面电阻的双曲面来设计低旁瓣卡塞格伦天线 ,给出了双曲面表面电阻值与所需的低旁瓣口径场分布理论值的关系式。计算结果表明 ,只要口径场分布的设计值在低旁瓣口径场分布的理论值上上下波动 ,就能获得与低旁瓣口径场分布的理论值较接近的旁瓣电平和口径利用效率。实测结果与设计结果基本一致。     

固态有源相控阵天线多阶振幅量化及副瓣特性的研究

本文研究了多阶振幅量化二维低副瓣固态有源相控阵天线的口径设计方法，结果表明，这种方法能够有效地降低固态有源相控阵的峰值副瓣电平，并且可适且于任意复杂口径天线。另外，对于随机幅相误差和单元（或Ｔ／Ｒ组件）失而引起的增益损失及峰值副瓣电平恶化也进行了分析。     

Sharp cutoff radiation patterns

A method is described for estimating the available slope (dB/ deg) for the design of a sharp cutoff radiation pattern with a given aperture size, sidelobe level, and ripple factor. Curves are presented which relate slope factor (dB/deg/wavelength of aperture), sidelobe level, and ripple factor. These curves are obtained by defining and evaluating a Chebyshev integral pattern function which is representative of a sharp cutoff radiation pattern.     

A Technique for the Synthesis of Line-Source Antenna Patterns Having Specified Sidelobe Behavior

A new method for the synthesis of line.source antenna patterns having prescribed sidelobe envelope functions is discussed. The patterns obtained are inherently nonsupergained and, in the sense of Taylor patterns, approach the narrowest beamwidth for the given sidelobe behavior. Sample patterns and corresponding aperture distributions, together with required design parameters, are given. The sidelobe envelope functions for those patterns having maximum gain for a given maximum sidelobe level are also presented.     

基于和声搜索的稀布线阵旁瓣电平优化*

采用和声搜索算法研究了带约束条件的稀布线阵峰值旁瓣优化问题.探讨了稀布阵综合中的天线口径、阵元数目以及峰值旁瓣的关系,并拟合了三者的数学模型.仿真结果表明,与现有优化算法相比,改进的和声搜索算法具有更快的收敛速度;在峰值旁瓣优化中,不同阵元数目可获得最佳的天线口径;而在固定天线口径条件下,少量的阵元可获得更佳的峰值旁瓣.天线口径、阵元数目以及峰值旁瓣的相互关系可为稀布线阵的优化设计提供参考和借鉴.     

基于IAA的毫米波人体三维高分辨成像算法

针对利用三维合成孔径技术成像的毫米波人体安检设备成像分辨力低的问题,提出一种将迭代自适应(IAA)技术与合成孔径成像技术相结合的波数域IAA成像算法。波数域IAA技术能估计出每个潜在位置所对应的信号源能量,具有分辨力高、旁瓣低且适合单快拍估计等优点。通过理论模型分析和仿真运算,将重构效果图与传统的匹配滤波方法重构效果图进行对比分析,验证了该算法的有效性;同时随着计算能力的提高,该算法的性能也得到提高。     

高效率低旁瓣天线口面场分布函数研究

在赋形双反射面天线中,口面场分布函数对天线电气性能起到至关重要的作用。口面场分布函数妆接影响天线的增益和近角旁瓣。在传统卫星通信地面站中,要求天线第一旁瓣电平在-14dB以下,口面利用率在90%左右,而射电天文望远镜要求天线第一旁瓣电平小于-20dB,口面利用率要求在85%以上。研究并给出了一种整个口面能量均匀分布而外边缘低锥销的口面场分布函数,可以满足高增益,低旁瓣的要求。     

消减旁瓣的衍射计算

由于光的衍射作用 ,使通过聚焦系统的激光束入射到特定靶面成一光斑 (主光斑 ) ,而在主光斑以外还有次级光斑圈 (旁瓣 )。为了消减旁瓣 ,结合理论分析和神光装置聚焦系统的设计 ,提出了一种新的系统孔径遮挡分割法 ,从光的衍射理论和实验证明这种方法是有效的 ,使旁瓣缩减     

An analytic nonlinear approach to sidelobe reduction

We propose an analytic technique for reducing sidelobe artifacts in synthetic aperture radar data. The technique, called leakage energy minimization (LEM), uses a spatially varying aperture function, the coefficients of which satisfy a simple optimality condition. The integrated sidelobe energy (or leakage energy) characterizing a given aperture weighting function is used as a metric for determining the likelihood of an aperture weighting. When applied to synthetic aperture radar data, the technique can effectively reduce sidelobe levels with negligible loss of resolution. The algorithm is computationally efficient, and its application requires no restrictions on the data sampling rate.     

Least squares pattern synthesis for conformal arrays

The problem of synthesising low sidelobe beams from conformal arrays consisting of few elements and large radius of curvature is addressed. Experimental results are presented for a 12 element array of linearly polarised elements forming a faceted array with radius of curvature 1.5 m. It is shown that by calculation of an aperture correcting matrix, sidelobe levels of 40 dB can be obtained from the array by application of conventional linear array Taylor weights. Beam steering is achieved by aperture phase tapering while low sidelobe levels are maintained     

DESIGN AND ANALYSIS OF MULTI-STEP AMPLITUDE QUANTIZATION WEIGHTED 2-D SOLID-STATE ACTIVE PHASED ARRAY ANTENNAS

An aperture design technique using multi-step amplitude quantization for two-dimensional solid-state active phased arrays to achieve low sidelobe is described. It can be applied to antennas with arbitrary complex aperture. Also, the gain drop and sidelobe degradation due to random amplitude and phase errors and element (or T/R module) failures are investigated.     

多阶振幅量化加权二维固态有源相控阵天线的设计与分析

本文论述了一种多阶振幅量化二维固态有源相控阵天线获得低副瓣的口径设计方法,这种方法可适用于任意复杂口径天线。另外,对于由随机幅相误差和单元(或T/R组件)失效而引起的副瓣电平恶化和增益下降也进行了分析。     

A mathematical theory of antenna arrays with randomly spaced elements

Various probabilistic properties of a large antenna array with randomly spaced elements have been studied. It is found that for almost all cases of practical interest the required number of elements is closely related to the desired sidelobe level and is almost independent of the aperture dimension, the resolution (or the beamwidth) depends mainly on the aperture dimension, and the directive gain is proportional to the number of elements used if the average spacing is large. As a consequence the number of elements required is considerably less than that with uniform spacings. Starting with a given number of elements and a given aperture size, it is possible to improve the resolution by a factor of ten, a hundred, or more by spreading these elements over a larger aperture with little risk in obtaining a much higher sidelobe level and a lower directive gain. In fact, this method offers a solution which is optimum in a certain statistical sense, i.e., all sidelobes are of equal level with equal probability. In addition, this analysis also gives a simple estimate of the sidelobe level of most nonuniformly spaced antenna arrays. In a number of such arrays studied by various investigators with high speed computers, the agreement found is remarkable.     

Line-source excitation for maximum difference slope with given sidelobe level

A method is described for computing the difference excitation of a linear aperture that provides maximum slope ratio with a constraint on the sidelobe level. Elementary Bessel functions are used in the computations.     

圆口径正馈抛物面天线的近场分析

分析了圆口径正馈抛物面天线的近场.采用口径场绕射积分求取了天线的近场及远场方向图,绘制了波束宽度、方向性和最大副瓣电平三个关键参数随场点距离的关系曲线.通过与物理光学法的计算结果对比,验证了该方法的正确性.仿真结果是:随场点距离的减小,波束宽度展宽,方向性减小,最大副瓣电平在一定范围内波动.场点在D2/λ外,远场近似的波束宽度误差小于1%;在0.5D2/λ外,远场近似的波束宽度误差小于10%;在0.5D2/λ内,不能采用远场近似.