非规则曲面共形阵列的优化设计

该文对一个共形在非规则曲面上的H形微带阵列进行了优化及设计。采用自适应混合遗传算法对此共形阵列的辐射方向图进行了优化设计。优化后的辐射方向图在水平方向几乎达到了全向辐射,俯仰面方向图集中辐射在水平方向。最后考虑到相位误差,对优化结果进行了误差分析。结果表明,该文所提出的优化算法对于非规则曲面上共形阵列的设计是有效和可行的。     

基于虚拟阵列变换的共形阵列信号DOA估计

共形阵列是指与载体表面共形的天线阵列,对载体空气动力性能影响小,在军用、民用等飞行器上具有广泛的应用。针对共形阵列信号处理中的角度估计问题,给出了一种基于虚拟阵列变换思想的共形阵列信号DOA估计算法。该算法首先对接收数据进行虚拟阵列变换,利用变换后的数据,采用ESPRIT算法和MUSIC算法相结合,实现了对共形阵列信号二维角度估计。算法对阵列形状限制小,真正实现了适用于任意共形阵列。以圆柱共形阵列为例,通过仿真实验验证了算法的有效性。     

共形阵列幅相误差校正快速算法

基于子空间的联合迭代算法可以实现对空间信源方位和阵列幅相误差参数的联合估计。当对共形阵列进行幅相误差校正时,由于其空域导向矢量不具有Vander monde结构,导致快速高分辨空间谱估计方法无法直接应用,而利用2维谱峰搜索实现空间方位估计的运算量较大,限制了算法在共形阵列上的应用。针对此问题,该文提出一种借助虚拟阵列实现共形阵列幅相误差校正的新方法。该方法利用虚拟阵列的特殊结构快速实现对信源的DOA估计,省去了谱峰搜索过程,因而运算复杂度低,便于工程实现。理论分析和仿真结果验证了所提算法的有效性,可为共形阵列的工程应用提供参考。     

基于改进粒子群算法的共形阵列天线综合

共形阵列天线的赋形方向图综合涉及大量的运算,成为现在研究的一大难点,目前对共形阵方向图综合的研究比较少,且所用算法存在理论复杂、耗时长的缺点。文中运用改进粒子群算法对圆环阵、圆柱阵方向图的综合进行了研究,仿真结果表明,改进粒子群算法能够较快地形成期望方向图,证明了该方法的有效性和实用性。     

低旁瓣球面共形随机稀疏阵列

针对平面阵列不能实现大范围空域扫描,角度分辨率不高的缺点,对比分析了球面共形阵列的辐射优点,后采用均匀随机排列的方法对球面共形阵列进行稀疏,最终在高角度分辨率和较低成本间实现了很好的性价比折衷,有很大实际意义。     

共形微带天线相控阵阵列的仿真优化设计

针对平面阵列天线的诸多缺点,设计了适用于工作频段34～36GHz的共形相控阵天线。依据共形微带天线阵列的设计思想及方法,选取了柱面微带贴片天线做阵列辐射单元,通过CST软件对天线的几何尺寸进行仿真和优化设计,得出了共形天线阵的各种性能指标。仿真结果表明：在该毫米波波段下设计的共形相控天线具有优良的性能,为今后设计出最优的天线阵提供了依据。     

椭球共形阵列增益与等效面积关系研究

为了解各种共形阵列天线增益在空间的分布情况,从而确定共形阵列的形状。以椭球共形阵列天线为例,给出了一种使用等效投影面积来估算共形阵列天线增益分布的方法。考虑天线单元作用范围影响,推导了各个来波方向等效投影面积的数学表达式。在推导出天线单元具体位置的基础上,根据波束合成原理,通过仿真得到了各个来波方向上的增益分布。对比可见,阵列增益的仿真结果与等效面积的数值计算结果曲线形状吻合,可以直接利用等效面积公式调节椭球长短轴比来改变增益。     

基于RWG MoM圆柱共形微带振子天线的全波分析

提出了一种分域求解法,解决了矩量法计算遇到的Sommerfield积分中Hankel函数奇异问题,实现了矩量法分析中全部阻抗矩阵元素的计算.采用三角面对基函数对圆柱分层介质上共形微带振子天线进行了理论分析.仿真验证了文中提出方法的有效性并分析研究了圆柱分层介质上z及ψ方向共形微带振子天线的电磁特性,计算结果与对应平面情况进行了比较.     

球面共形微带天线的优化设计

针对球面共形微带天线带宽窄的缺陷,采用自适应差分进化算法结合矩量法成功实现对球面共形微带天线的优化设计。对自适应差分进化算法中的种群初始化、控制参数的选择等方面进行了详细的讨论。在搜索过程中,提出一种"先测向后定位"的搜索策略,首先采用粗优化方式找到控制天线性能基因的大致位置,然后在找到的位置进行细优化,进一步提高天线的性能。这种粗、细优化相结合的方式在保证优化效果的情况下,大大降低种群的数量,提高了优化效率。最后,分别优化出宽频带以及工作在双频点的球面共形微带天线,优化结果与仿真软件对比,验证了本文分析处理的正确性与有效性。     

基于LCP柔性材料的柱面共形阵列天线设计

采用新型液晶高分子聚合物(LCP)作为基板材料,通过模拟仿真设计了一款工作频率在35GHz的四单元微带共形贴片天线。该共形贴片阵列的增益可以达到13.2dB,3dB波瓣宽度为42.2°,副瓣电平达到-20.6dB。     

基于Matlab的阵列天线数值分析

为了能够快速有效地设计阵列天线,提出了在阵列天线设计过程中引入Matlab进行辅助设计。通过Matlab高效的数值计算能力和强大的绘图功能,直观地归纳出天线性能随着天线结构参数的变化情况,从而为阵列天线设计提供依据。实验结果表明,Matlab高效的数值计算能力可以直观的为阵列天线设计提供指导思路,从而可以快速有效地进行阵列天线设计。     

Design of a small conformal array

The principal objective of this investigation was to determine how to efficiently excite a small conical body over a 2:1 frequency bandwidth such that a prescribed minimun value of gain is exceeded in a60degconical sector about the forward axis of the cone. To achieve the necessary bandwidth, two approaches have been considered. First, an electrically small moderately efficient tunable antenna can be employed to excite currents on the cone. Second, one can employ a wide-band antenna having at least a 2:1 bandwidth. This latter approach was investigated theoretically and found to be feasible but experimental confirmation was not attempted in deference to the first approach that has the potential of greater gain (efficiency). To demonstrate the validity of the first approach a four element conical array was constructed and is described in this paper. Experimental results agreed well with theoretical expectations.     

Phase synthesis of conformal array antennas

A new phase synthesis method for planar and conformal arrays is presented. The method is based on approximate linearized equations for small phase changes in the excitations, which can be determined by the least-squares method and used iteratively to obtain the final solutions for the excitation phases. Several different kinds of contoured beams can be used in the same array by using only phase shifters in the elements, as demonstrated in the calculated synthesis examples     

共形天线阵列极化分集问题

在多模复合制导模式下,被动雷达导引头(PRS)可采用共形天线阵列接收入射信号。共形天线通常为线极化天线,将其摆放在弹体的一周,天线阵列的接收信号将出现极化分集问题。针对该问题,建立了在极化分集条件下共形天线阵列接收信号的数学模型,理论推导极化分集对干涉仪方法测向性能的影响,以及分析干涉仪方法能够正确测向的前提条件,通过计算机仿真实验验证了研究结论的有效性。该文给出了解决共形天线阵列极化分集问题的研究思路。     

Analysis of curved optical waveguides by conformal transformation

The method of conformal transformations is applied to the analysis of waveguide bends. Equivalent structures are obtained that permit solution by traditional methods of optical waveguide analysis. Losses associated with both curvature and with the transition from straight to curved guides are discussed and simple first-order expressions that describe the dependence of the losses on waveguide parameters are derived.     

艇载共形稀疏阵列天线雷达成像研究

基于平流层飞艇平台,研究了共形稀疏阵列天线雷达对静止目标成像及对运动目标探测的问题。针对三叶玫瑰线艇身模型,提出了共形稀疏阵列天线的布阵方式。雷达采用实孔径方式成像,各子阵同时发射多脉冲频分正交信号。利用各子阵多发多收的回波信号,采用后向投影(BP)算法完成各子带信号对静止目标的成像处理,再将子带信号成像结果相参累加以提高静止目标成像的距离向分辨率;将各子阵一发多收的多脉冲回波信号变换到距离-多普勒域,完成静止杂波抑制,对各子带信号采用压缩感知(CS)的方法在二维空间实现对运动目标图像的重建,再将子带信号重建结果非相参累加以提高运动目标探测的信噪比。仿真实验验证了本文方法的有效性。     

一种全向共形微带贴片天线阵的设计

设计制作了一款新结构的垂直极化全向微带天线。天线利用分布于立方体侧面上的四个对称性天线单元的单向辐射实现全向辐射,通过单元辐射结构上加载两臂,增加天线的谐振点,展宽设计天线的带宽,对该天线进行了仿真和测试。结果表明,仿真与测试结果基本吻合。设计的天线带宽覆盖了1.7~2.8 GHz,反射系数S11<–10 d B的相对带宽达到49%,在整个频带内实现了全向辐射。天线结构简单且紧凑,易于加工,可用于移动通信领域。     

Mutual coupling analysis of a conformal array of elements on a cylindrical surface

The analysis of multiport antennas may be approached by resorting to the powerful concept of eigenexcitations of the structure. They may be defined as the eigenvectors of the admittance matrix, i.e., those sets of voltages and currents at the antenna terminals which are related simply by a proportionality factor (eigenvalue of the admittance matrix). Similarly, the eigenexcitations may be alternatively defined as the eigenvectors of the scattering matrix. The analysis for this special kind of excitation is sometimes relatively easy. The general case may then be treated by utilizing superposition principle. An array of infinitely long longitudinal slots equispaced on a conducting cylinder is analyzed in detail. The eigenvectors of the admittance and scattering matrices are easily found because of the symmetry of the structure. Expressions for the eigenvalues of these matrices, and for the radiation patterns due to the array eigenexcitations, are found in the form of infinite series rapidly convergent (even for cylinders of large radius). By using linearity an expression for the radiation pattern of the single excited element in the array environment (the main result of this paper) is then established. Expressions are also given for the coupling (or scattering) coefficients. A number of numerical examples with different cylinder radii are discussed in detail.     

Efficient electromagnetic analysis of a doubly infinite array ofrectangular apertures

An accurate and rapid method is presented for solving the magnetic field integral equation for the equivalent magnetic currents representing a doubly periodic array of rectangular apertures. Ewald's method is used to accelerate the summations associated with periodic Green's function, allowing the Green's function to be determined to nearly machine precision. Galerkin's method is used to discretize the integral equation with Chebyshev polynomials used as the basis and testing functions. Efficient treatment of the “self-term” singularity is emphasized