不规则子阵固态有源阵多阶振幅量化

对不规则子阵固态有源相控阵多阶振幅量化进行理论研究,给出其设计原理与途径。研究结果表明,利用较少量化台阶数,多阶振幅量化阵可实现较低的副瓣电平。尤其对于发射阵而言,该方法有利于减少组件品种和设计成本,适于工程应用。文中给出设计实例,验证了不规则子阵多阶振幅量化的正确性。     

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亚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”。     

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。     

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。     

子阵幅度加权的低副瓣技术研究

在大型相控阵天线中采用子阵幅度加权来降低副瓣是一项简单且实用的技术,并且成本较低,但是在副瓣区域会出现高量化瓣（栅瓣）。如果在阵元级进行幅度加权,就不会出现量化瓣,且会取得非常好的低副瓣的效果。但是由于大型相控阵天线阵元数目比较多,所以采用阵元幅度加权馈电系统会比较复杂,而且成本较高。解决这个问题一个折中的方法就是在子阵进行幅度加权,同时在每个子阵中具有相同序号的阵元加权相同的系数,然后利用子阵系数和阵元系数的乘积来近似只有在阵元进行加权时的期望加权系数。这个近似的方法要比单独采用子阵幅度加权的副瓣电平好（在这里假设所有的子阵都是均匀子阵）。该设计比全部阵元幅度加权简单,而且降低了成本。     

多联骨牌子阵天线阵列低副瓣综合

在大型阵列天线的设计中,应用不规则的多联骨牌子阵可以有效地抑制栅瓣,降低工程成本。在多联骨牌子阵划分阵列的基础上,文中通过遗传算法进行幅度和相位优化,对仿真结果进行对比和分析研究,实现了多联骨牌子阵天线阵列方向图的低副瓣性能和较高的口径效率。     

阵列雷达最优子阵划分研究

在大型的相控阵天线中,为降低系统复杂性及应用成本,需要采用子阵划分技术对天线阵面进行最优划分。首先总结了基于子阵划分的相控阵雷达信号处理流程,在此基础上,从低副瓣的多波束、子阵级自适应干扰抑制等不同方面研究子阵划分技术。对现有子阵划分的研究途径、划分的方法以及各自特点进行研究和归纳。在抑制波束旁瓣方面,建立了求解最优子阵划分的优化数学模型;在自适应抗扰方面,分析了栅零点等影响子阵级自适应处理性能的因素。最后提出了最优子阵划分问题的进一步研究方向。     

随机幅相误差对线阵方向图最高副瓣电平的影响研究

副瓣电平是天线的重要技术指标之一,较低的副瓣电平可以减弱杂波影响、提高雷达的抗干扰能力。但在实际设计天线的过程中,不可避免的会引入随机误差,使得阵列的口径分布发生变化,直接影响天线阵的性能。随机误差的引入最终都可以表现为阵列各个单元的幅度误差和相位误差,故需要分析随机幅相误差对阵列天线副瓣电平的影响。本文以此出发,应用统计学理论,得到计入随机幅相误差后阵列副瓣区副瓣电平的统计特性,并由此分析在整个副瓣区域内最高副瓣电平的统计特性。结合计算机仿真,证明分析计算结果的正确性。     

随机误差对模块化阵列天线副瓣的影响

推导了相位误差、单元位置误差和子阵位置误差的取值范围与模块化阵列天线副瓣累积概率的关系,以及单元位置误差、子阵位置误差与整体位置误差的关系.通过实例说明,激励幅相误差、单元位置误差和子阵位置误差,对实现超低副瓣都是至关重要的.     

K波段低副瓣波导缝隙驻波阵设计

本文设计了一种 K 频段低副瓣波导缝隙驻波阵天线,给出了实现低副瓣的方法。设计副瓣电平为-27dB,缝隙幅度分布按-30dB 泰勒分布计算,结合高频仿真软件 Ansoft HFSS 对各缝隙归一化导纳进行计算,建立仿真模型并优化天线各参数。依据设计结果加工实物并测试其方向图及增益。测试结果表明,该天线在工作频带内波束宽度约 3°,副瓣电平小于-27dB,工作频带内增益大于 30.8dB,仿真结果与实测结果相符,设计满足指标要求。     

Low sidelobe design considerations of large linear array antennas with contiguous subarrays

Design of large array antennas with contiguous subarrays and having very low sidelobe levels of the order of - 40 dB is discussed. The effects of the amplitude quantization, phase quantization and the number of subarrays on the radiation patterns of contiguous arrays are studied, and results are presented for both sum and difference patterns. A linear array of length200 lambdawith different number of contiguous subarrays and having true time delay steering at the subarray level and phase steering at the element level is analyzed. It is shown that peak sidelobe/quantization lobe levels better than - 39 dB for the sum patterns and better than - 35 dB for the difference patterns can be realized withinpm 60degscan and 0.3 percent bandwidth.     

A frequency-controlled active phased array

A frequency-controlled active phased array is introduced for cost-effective base-station applications. The array realizes simple LO-controlled beam steering with a fixed RF frequency, but without phase shifter components. Primary beam squint and pattern distortions, often seen in typical frequency-controlled phased arrays, are substantially reduced by the use of our heterodyne-mixing scheme and new feed network structures. The MMIC amplifiers provide more than 20 dB gain for a desired RF signal at 20 GHz, and effectively suppress the unwanted sideband and spurious LO by more than 40 dB. The K-band transmitter array demonstrates up to 40 degree beam-steering within 0.5 degree scan error and less than 1.3 dB gain error during scanning.     

The peak sidelobe of the phased array having randomly located elements

A formula is derived for the peak sidelobe level of a phased array in which the elements are randomly located. The parameters of the formula are the number and size of the array elements, size of the array, wavelength, beamsteering angle, and signal bandwidth. The theory is tested by measurement of the peak sidelobe of several hundred computer-simulated random arrays. Unlike the case for the conventional array the effect of spatial taper (nonuniform density of element location) upon the peak sidelobe level is minor. The peak sidelobe of the two-dimensional planar array is approximately 3 dB higher than that of the linear array of the same length and same number of elements.     

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.     

约束优化实现超低副瓣相控阵的多阶振幅量化

利用约束非线性最优化方法研究超低副瓣相控阵激励振幅的量化综合问题,通过对相控阵天线优化模型加入适当的约束条件,实现了二维可分离超低副瓣相控阵天线多阶振幅量化和单元间互耦的直接修正,该方法适用于各种形式相控阵天线的量化综合,最后给出了一些计算结果。     

Low sidelobe level in almost uniformly excited array

The sidelobe level of a uniformly excited array can be lowered significantly by reducing the amplitudes of a minority of its elements. The authors describe a genetic algorithm method for determining which amplitudes to reduce and by how much, and illustrate the method by applying it to a 100-element linear array     

有源相控阵天线的近场校准

为实现对相控阵天线的校准,降低幅相误差和阵元失效对天线性能的影响,提出了一种考虑互耦效应的近场校准方法。在利用近场扫描法完成逐一通道校准的基础上,使用旋转矢量法进行二次校准。在应用旋转矢量法（ REV)时,为使被测信号的变化明显,将大规模相控阵天线分为中间、边缘区域进行分区校准。通过二次校准可判定阵元是否失效,提高相控阵天线的幅相一致性;通过分区校准减小阵元间互耦的影响,缩短校准时间。仿真结果表明：此方法用于大型相控阵的校准具有较高的准确性,可改善校准结果。     

子阵级相控阵差波束旁瓣抑制新方法

针对采用单脉冲技术的相控阵系统,在子阵级采用数字加权抑制差波束的旁瓣.利用遗传算法优化子阵级加权,构造了加权向量和方向图等两种适应度函数.对只使用一种适应度函数的常规遗传优化方法进行了改进,提出分阶段、多适应度函数的方法:将优化过程分为两个阶段,并分别使用加权向量和方向图参数作为适应度函数.改进方法提高了遗传优化的稳定...     

Design of phased arrays in terms of random subarrays

Analysis and systematic design of uniform phased arrays with subarrays of unequal sizes are absent from the literature, in spite of the appeal of such architectures to wide-bandwidth beam steering. Unequally sized subarrays are expected to outperform identical, contiguous subarrays in terms of array grating lobes, A uniform linear array that is divided into contiguous subarrays of random sizes is studied. Each array element is connected to a phase shifter, and each subarray is implemented with a common time delayer. Closed-form expressions for the average array factor and the variance of the array factor are developed. These expressions enable the formulation of a design procedure that includes the estimation of the peak-grating-lobe level in terms of the probability that the grating lobes will exceed a desired level     

Constrained feed technique for subarrays of large phased arrays

A technique is presented which combines the subarraying qualities of constrained dual transform beamforming sections and partial overlapping networks to produce arrays of contiguous subarrays. This approach is shown to facilitate wideband scanning or limited field of view coverage with a minimum number of controls and low sidelobes