基于遗传算法多子阵平板天线旁瓣电平优化

从理论上分析了多子阵平板天线的方向图特性,指出其旁瓣电平难以通过传统的不等幅馈电技术得以抑制.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,并在间距优化的基础上讨论了天线单元方向性与不等幅馈电技术对旁瓣电平的影响.仿真结果证明了理论分析的正确性,表明子阵间距优化可以显著降低天线的旁瓣电平,且...     

基于相控阵的全空域多目标测控天线分析

基于抛物面天线的测控系统,已经不能满足全空域内同时多目标测控的需求。针对单站全空域多目标测控中存在的问题,提出了基于球面相控阵的全空域多目标测控天线体制。比较了全空域多目标相控阵测控天线形式,在研究球面相控阵天线原理的基础上,对辐射单元及子阵布局进行了分析与设计,对波束合成后的天线方向图进行了仿真。结果表明:基于球面相控阵的全空域多目标测控天线能够有效解决未来全空域多目标同时测控的需求。     

一种全空域覆盖卫星通信多面相控阵天线

设计了一种可以覆盖全空域的卫星通信相控阵天线,采用七面阵圈成台体的形武,每一面阵上设置四单元的相拉阵天线阵列,其波束分别覆盖空域中不同的部分,其中顶部的面阵形成的波束覆盖上半空间的部分区域,侧面的六个面阵产生的波束分别覆盖低仰角空域。在系统内部采用开关切换的形武,对不同面阵的工作状态进行控制。在每一面阵申,由四单元组成的相控阵可进行波柬扫描,以扩大波束覆盖范围。系统内部的传感系统和有源功率控制设备实现天线对卫星的自跟踪功能。该典型设备可以用于各种移动载体上。     

宽带相控阵天线延迟线分析

采用频率无关移相器的相控阵天线的波束指向会随频率发生变化,实时延迟线是提高宽带相控阵天线波束指向精度的重要方法。分析了子阵级采用延迟线,单元级使用移相器的宽带相控阵天线副辫特性,发现当工作频率改变时,由于阵列存在周期相位误差导致天线副瓣电平抬高。针对此问题,提出单元级精细延迟线方案,消除周期相位误差对天线副瓣的影响。仿真结果表明,这种方法在扩展相控阵天线带宽的同时,明显改善了天线的副瓣特性。     

有源相控阵天线瞬时宽带性能改善研究

采用无色散特性的模拟或数字移相器会导致天线波束指向随频率发生变化,即相控阵天线的孔径效应。工程上一般在子阵级别上采用色散特性的实时延迟线拓展相控阵天线瞬时带宽,但是子阵级延时量化误差会产生周期性栅瓣,导致天线副瓣性能恶化。文中提出在通道(或多通道收发组件)上设置小位延迟线、与子阵级大位延时线叠加使用,消除或改善子阵级延时误差造成的性能恶化。结合X波段有源二维阵列天线,对单元级、子阵级、子阵+单元两级三种情况进行了仿真。仿真结果表明,子阵+单元两级延时方法在扩展相控阵天线瞬时带宽的同时,能明显改善相控阵天线的副瓣特性,且具有较强的工程可实现性。     

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.     

X波段双层16单元正方形径向线螺旋子阵的设计

矩形径向线螺旋子阵的设计是高功率高增益径向线螺旋阵列天线研究的基础,提出并设计了一个X波段双层16单元正方形径向线螺旋子阵,阐述了子阵的工作原理,简要介绍了X波段的辐射单元和耦合探针,重点分析了双层径向线馈电系统,从而得到了一个X波段的子阵模型,并对其进行了数值模拟,结果表明该子阵在8.6～10.1GHz的频带范围内,天线反射系数小于0.1,在9.0～10.0GHz的频带范围内,天线增益大于18.45dB,副瓣电平小于-11.68dB,轴比值小于1.66。     

一种新颖的共形阵非均匀子阵的优化算法

提出了一种新的同时对共形阵非均匀子阵分区和子阵幅度激励进行优化的多目标进化算法，为此设计了新的多目标函数，通过在改进的强度 Pareto 进化算法(SPEA2)使用克隆选择算子和双交换遗传操作算子，从而提高搜索效率和收敛性，可以有效改善整个阵列的辐射特性。 在系统仿真中，结合工程化实际应用，本文提出的 MOEA 算法对 20×20 阵列进行非均匀子阵分区和对各个子阵的幅度激励优化，仿真结果表明其天线阵列在扫描空域的峰值旁瓣电平(PSLL) 以及方位和俯仰波束宽度等性能参数得到明显改善，该方法对改善整个阵列的辐射特性是有效的。     

机载X 波段圆口径平面阵列天线的子阵划分研究

针对机载X 波段圆口径相控阵天线,文中提出了五种典型子阵划分方法,以解决相控阵天线瞬时宽带工作时宽角扫描波束色散的难题,同时,实现指向角偏差、第一副瓣电平、增益、平均副瓣电平、最大副瓣电平等典型参数性能最优化;在仿真分析基础上,总结了子阵划分方法与天线性能之间对应关系。     

部件失效对有源相控阵天线性能的影响分析

有源相控阵天线系统的部件失效会造成天线增益、副瓣电平等性能参数的恶化。在考虑了天线单元幅度和相位的随机误差呈正态分布后,以部件失效的概率分布为依据,分析了包括天线单元失效、子阵失效以及组件失效情况下,天线性能随之变化的趋势。通过算例仿真得出,在文中建立的不同部件失效的数学模型下,天线增益的变化相对平缓,而副瓣抬升则相对较大。计算结果及结论可用于实际相控阵天线性能的评估和工程设计。     

大型阵列天线子阵划分及栅瓣抑制方法

利用遗传算法(genetic algorithm, GA)将大型阵列划分为非均匀邻接子阵,以主旁瓣比作为适应度函数,并对遗传操作增加约束条件,得到具有栅瓣抑制能力的子阵结构。提出了基于子阵级的波束扫描方法,在每个扫描分区内无需改变阵元权值,仅通过子阵级数字波束形成即可完成阵列的波束扫描,并分析了不同扫描角对阵列方向图的影响。为了抑制大扫描角带来的高旁瓣,运用自适应原理使子阵级方向图在高旁瓣位置形成凹陷。分析与仿真结果表明,该方法能够进一步提高阵列方向图的主旁瓣比,增加扫描分区的范围。      

基于方向图综合和空域插值的大型阵多波束形成技术

为了克服大型阵阵元级多波束形成的造价,复杂度和子阵级多波束形成的抑制栅瓣困难的问题,提出了一种方向图综合与空域插值相结合的方法,该方法既可以实现在任意方向上形成多个波束,又可以避免使用大量的数字权,简化了波束形成网络,具有较高的工程实用价值。计算推导和仿真结果均表明此方法是有效的。     

An optical subarray antenna having antenna nulling applications

A linear subarray type optical antenna is considered for adaptive applications. The antenna has a small number of subarrays whose radiation patterns cover the region occupied by targets and interference in a near-optimum fashion. The subarray design is such that very low subarray pattern sidelobes are produced, thereby allowing operation in the presence of additional strong interference outside the subarray beams. The design of a near-optimum sheet metal antenna to perform these functions is described and the performance is analyzed.     

A low-sidelobe partially overlapped constrained feed network fortime-delayed subarrays

Completely overlapped space-fed subarrays have been shown to provide sufficient pattern control to enable (modestly) wide-band arrays using time delays at the input to each subarray and phase shifters at the array face. These configurations are bulky, but have been proposed for space-based use as well as for certain ground-based applications that do not have severe volume constraints. Other applications for space-based and airborne radar require much more compact, constrained array feed networks, but until now there have been few appropriate constrained networks for inserting time delay at the subarray ports without causing high sidelobes. This paper describes one such network that, at the outset, provided far lower sidelobes than the usual contiguous subarrays, but retained closely spaced high lobes near the main beam. This paper presents a synthesis procedure that alters the subarray patterns and reduces nearly all array sidelobes to levels determined by tolerance errors. Several examples are presented that synthesize sidelobes at -40 dB. The resulting network operates over 70% to 80% of the maximum theoretical bandwidth     

一种低旁瓣子阵级自适应波束形成方法

相控阵雷达在军事上的应用日渐广泛,要满足雷达系统性能日益增长的需求,必须采用大孔径天线,以便得到更高的角度和距离分辨率。大型面阵的全自适应波束形成计算量庞大,采用子阵级自适应波束形成可以用较小的代价实现较优的自适应性能。研究了等幅平面阵的子阵级波束形成技术,并针对非均匀划分的子阵结构,采用了子阵级通道噪声功率的归一化处理。该方法不仅能够有效降低子阵级方向图的旁瓣电平,其自适应性能保持良好。仿真验证了该方法的有效性。     

多联骨牌子阵天线阵列的波瓣性能研究

在相控阵天线阵面设计中,为降低系统复杂性及工程成本,通常采用子阵技术来实现。同时,为了较好地抑制栅瓣,文中引入了多联骨牌子阵,给出了两种采用不同子阵结构和排列方式的天线阵列,并对有限视场下的扫描特性进行了仿真。通过对仿真结果进行对比和分析研究,验证了多联骨牌子阵实现阵列方向图低副瓣的有效性。最后,提出了采用多联骨牌子阵进行天线阵列设计需要进一步研究的方向。     

Reducing grating lobes due to subarray amplitude tapering

Subarray amplitude tapering is a simple, lower cost method to generate low sidelobes in an antenna's far-field pattern. Unfortunately, this simple technique also generates unwanted grating lobes. Placing the exact amplitude taper at the element outputs produces the desired far-field pattern, but the feed architecture is complicated and expensive. An alternative to these two techniques is described. A trade-off exists between sidelobe performance and simplicity of design. This trade-off consists of amplitude tapering the subarray outputs and the element outputs in such a way that the element amplitude tapers are identical for every subarray. In this way, the amplitude taper approximates the desired taper much better than subarray tapering alone, yet all the subarrays are identical. Thus, the feed design remains very simple.     

Broadside printed antenna arrays built with dissymmetrical subarrays

The analysis and realisation of printed antenna arrays with low sidelobes using a tapered excitation are described. The array is divided into several independent subarrays, fed at their centres by a low-loss corporate feed network. To achieve the correct radiation pattern, each subarray must exhibit a dissymmetrical source excitation; equations are derived to calculate the transformation ratios along the linear series subarrays. Theoretical and experimental results are in good agreement.<>     

Stacked quasi-elliptical patch array with circular polarisation

A simple stacked subarray antenna with circular polarisation is presented. The antenna is based on a quasi-elliptical patch antenna fed with a 45deg offset microstrip line and a circular patch stacked on top of it via an air substrate. The single-element circularly polarised antenna is sequentially rotated into a four-element synchronous subarray resulting in improvement in antenna performance in terms of impedance bandwidth, gain and axial ratio. The antenna is experimentally verified and the results are reported     

多波束形成的信号接收系统设计

介绍了多波束形成的原理,对接收系统的原理、组成、各部分的特点及实现方法做了详细地说明,着重介绍了ADC同步采样和基于多相滤波正交变换,最后对系统的电磁兼容设计做了简单介绍.