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。     

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。     

Be/spl acute/zier representations for the multiobjective optimization of conformal array amplitude weights

For conformal phased arrays, generally the excitation amplitude of the array elements must be adjusted in order to maintain low sidelobes as the array is scanned. While the desired phase weights for maximum gain are deterministically set by the array geometry and scan angle, the representation of optimum low sidelobe amplitude weights remains an open problem. Following up on prior work using the efficiency-constrained optimization of a modified Bernstein polynomial for low sidelobe conformal array synthesis, a Be/spl acute/zier surface is shown to provide a good representation of the optimized amplitude weights with a reduced number of parameters, while demonstrating /spl epsiv/-constraint multi-objective optimization of conformal aperture efficiency versus sidelobe level. These results are extended to include a Be/spl acute/zier volume representation for the multiobjective optimization of conformal aperture efficiency versus both sidelobe level and scan angle.     

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。     

Reduction of sidelobes in uniformly excited arrays with element pattern control

Uniformly excited arrays of identical elements suffer from high close-in sidelobes. Suppression of sidelobe levels can be achieved by tapering the aperture amplitude distribution, but a more complex feed network results. A novel form of amplitude tapering is described, in which element pattern control in uniformly excited arrays is shown to theoretically reduce close-in sidelobe levels.     

Phase-only control of antenna sum and shaped patterns through nullperturbation

Satisfactory sum or shaped antenna radiation patterns can often be synthesized by modifying just the phase distribution of an initial excitation by an arbitrary amplitude distribution. As examples, we calculate linear and circular apertures with uniform, Taylor, or cosine-section amplitude distributions, affording symmetric sum patterns with low sidelobe levels or symmetric shaped patterns with low ripple and sidelobe levels; linear aperture distributions, affording patterns with low sidelobe levels on one side of the beam; and planar arrays, with uniform or cosine-section amplitude distributions affording φ-symmetric or elongated-oval footprints     

Low sidelobe aperture distribution of multistep amplitude quantization with pedestal

A low sidelobe aperture design method of multi-step amplitude quantization with pedestal is proposed, and general analysis and formulas are described. The computation results compared with our previous method "Multi-Step Amplitude Quantization(MSAQ)" on peak side-lobe level, aperture efficiency, normalized input power and sidelobe degradation with tolerance are given. It is shown that, under the same conditions, the method presented in this paper is better than the MSAQ.     

Further discrete optimizations for continuous aperture illuminations

Two applications of an iterative procedure to establish a means of optimizing theoretical low sidelobe antenna patterns are discussed. Examples described consider discrete element linear array antennas where the parameters involved in the optimization process are coefficients ordinarily associated with continuous aperture illuminations. One application uses the iterative procedure to control far-out sidelobe levels of the far-field pattern to establish array element excitations appropriate for low sidelobe behavior throughout the entire visible region of space. The other application uses the procedure to establish beam port amplitude weightings at a minimum number of beam ports in a multibeam feed network also suitable for low sidelobe antenna pattern behavior.     

Sidelobes control of solid-state array antennas

An aperture design is described for two-dimensional (2-D) solid-state phased arrays that transmits low sidelobes. A five-step amplitude distribution for the aperture was optimized by a gradient search method to achieve -36-dB peak sidelobes. The optimized configuration was applied to a sample array of 36 columns by 14 rows, with 400 modules divided into five groups of power levels. The array performance with the actual module lattice structure taken into account is discussed. Gain drop and sidelobe degradations due to random amplitude and phase errors are also studied     

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。     

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。     

Sidelobe suppression in an E-plane sectoral horn antenna

A finite-difference method is used to design a sectoral horn antenna that uses corner channel inserts to produce a tapered aperture amplitude distribution in the E-plane. The channel inserts effectively suppress sidelobe levels in the radiation pattern. Good agreement is found between predicted and experimental far-field distributions.<>     

混合扫描多子阵平板天线旁瓣电平优化研究

多子阵技术是平板天线动中通降低天线系统高度的重要方法,但其离散口径却带来了高旁瓣,且难以通过传统的不等幅馈电技术得以抑制.文中从理论上分析了混合扫描多子阵平板天线的方向图特性,给出了几种降低旁瓣电平的方法.以降低天线扫描范围内的最高旁瓣电平为目标,采用遗传算法对子阵间距进行优化研究,仿真结果表明子阵间距优化可以显著降低天线的旁瓣电平.该方法与分析结果可为多子阵平板天线的设计提供参考.     

大型稀布相控阵天线设计及其旁瓣电平研究

本文对大型稀布相控阵天线设计及其旁瓣电平进行了研究.在用适当随机法设计稀布阵天线并对三种孔径尺寸,三十种孔径参考幅度分布,九种稀布率,用大周期随机数计算了45000个辐射孔径单元稀布排列方案及其全空域立体波瓣后,首次揭示了一些有价值的结论.最后,用数学回归法给出了精度较高的旁瓣电平计算公式.     

Sidelobe suppression of planar array antennas by the multistage decision method

The sidelobe level of a planar array antenna with equal amplitude excitation can be suppressed by element thinning. The method of element thinning employed here is a kind of multistage decision procedure or steepest descent approach. Although this method gives the local optimum results, the reduced sidelobe level is assured to be within the obtained level over the whole radiation region. The sidelobe level, for example, can be suppressed -29.7 dB where the array contains 3120 elements arranged within a circular aperture capable of 5815 elements if fully filled. The computation time is also discussed, and it is shown that the computation time decreases drastically by the use of the design method.     

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     

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。     

Carrier-to-noise ratio and sidelobe level in a two-laser modeloptically controlled array antenna using Fourier optics

The carrier-to-noise ratio of the microwave signal and the reduction of the antenna sidelobe are discussed for an optically controlled array antenna whose microwave aperture distribution is generated and controlled using Fourier transform and optical/electrical conversion. A two-laser model using two laser diodes whose frequency difference is set to the desired microwave frequency is proposed and compared with a single-laser model using an external modulator. The two-laser model seems to be favorable from the viewpoint of available laser diode output power. The required laser output for the two-laser model can be about 10 dB less than that for the single-laser model. Moreover, relationships between the antenna radiation characteristics and the aperture size of an image mask are investigated. It is clarified that the sidelobe level can be reduced about 20 dB without changing the gain and beamwidth by using a reference optical beam with a tapered amplitude distribution     

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.     

Pattern characteristics of linear arrays using the constrained least squares distribution

The constrained least squares (CLS) distribution is a method for obtaining distribution functions that yield low sidelobe patterns with specified constraints on the aperture efficiency, and are especially useful for the transmit patterns of active array antennas. The widely used Taylor distribution optimizes only pattern performance while the CLS distribution optimizes pattern performance while taking into account the constraints on both the peak element amplitude and the total effective radiated voltage (ERV) of the aperture distribution. The paper compares the pattern characteristics of linear arrays with CLS and Taylor distributions. The results help to establish guidelines on when a CLS distribution would be preferable over a Taylor distribution when a specified aperture efficiency is important.