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。     

球面共形阵数字波束发射阵列的实现研究

针对高空无线通信平台的应用环境,提出并实现了一种基于球面共形阵列天线发射数字波束形成的方法。在分析了可用于空中平台的球面共形阵列天线的基础上,利用粒子群算法对球面共形阵进行权系数优化,将得到的最优权值进行波束赋形并通过FPGA来实现,在FPGA内用DDS算法和查找表的方法实现对输出信号的幅度和相位调整。对天线单元的各路信号进行仿真和实测,并对仿真结果与实测结果进行对比,结果表明,发射DBF的仿真结果与实测结果基本一致。     

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。     

随机错位子阵阵列天线及其优化设计

针对大型的二维平面阵列天线,将随机布阵的概念应用于子阵布阵中,提出基于子阵的随机错位布阵方式,并采用二进制粒子群算法对随机错位子阵的错位方式进行了优化.仿真结果表明:采用随机错位子阵布阵方式,通过粒子群算法优化后,平面阵列天线可以在扫描范围内得到较低的旁瓣,避免了栅瓣的出现.     

自适应动态Meta粒子群优化算法综合多方向图共形阵列

基于全波仿真得到的广义阵元有源方向图,该文提出一种用于综合多方向图共形阵列的新方法:自适应动态Meta粒子群优化(ADMPSO)算法。在传统Meta粒子群优化(MPSO)算法基础上,定义了优势子群和非优子群的概念,并通过植入非优子群裁减、优势子群规模膨胀以及惯性权重自适应更新等机制,实现了优化过程中多子群的自适应动态调整,全面提高了算法性能。ADMPSO成功用于12元微带锥面共形阵列非赤道面的多方向图综合,综合过程考虑了由共形载体导致的阵元极化指向各异特征,在公共激励存在约束情况下,使阵列同时实现了笔形、平顶,以及余割平方波束总功率方向图,其与该阵列全波数值仿真完全吻合,优化结果和收敛速度相比于其他算法均有显著改善。     

基于机电耦合的有源相控阵天线辐射和散射特性综合优化

针对有源相控阵天线的雷达散射截面(Radar Cross Section,RCS)计算复杂、缩减困难,以及RCS与辐射性能难以兼顾问题,基于阵面结构变形与安装引起的辐射单元位置偏移分析,利用辐射单元相位误差,建立了有源相控阵天线阵列散射因子RCS的机电耦合模型.并基于该耦合模型,应用粒子群优化算法,优化阵面所有辐射单元的安装高度,以实现有源相控阵天线辐射性能和散射性能的全优.仿真结果表明,所建立的耦合模型及综合优化方法能够在保证有源相控阵天线辐射性能的条件下,有效缩减其RCS,具有重要的工程应用价值.     

锥体共形相控阵天线的特性分析

基于电磁场理论推导了锥体共形相控阵天线的阵因子。与平面相控阵天线相比,锥体共形相控阵天线单元间的空 间相位差既与阵元的轴向位置有关,又与阵元的周向位置有关。因此,在进行锥体共形相控阵天线设计时,除采用二维相 控阵形式外,尽量避免采用一维相扫锥体共形相控阵天线。     

基于PSO/FDTD的波导缝隙天线优化设计

设计了一种16阵元波导缝隙天线,其阵元在波导宽边中心线一侧排列。该设计采用泰勒分布进行阵列综合,利用粒子群优化算法(PSO)与时域有限差分法(FDTD)在不同偏置位置对谐振长度进行优化。由于该天线属于非谐振式波导缝隙阵,设计的关键是调整缝隙对宽边中心线的偏移。仿真结果表明天线指标与设计要求吻合,证明了设计方法的可行性。     

一种微带反射阵列天线单元带宽拓展方法

在微带反射阵列天线设计中,采用大小不同、结构相似的多个空心单元于同一层面上嵌套形成组合单元,可以拓展单元带宽.通过几种单元实例计算对比和实验阵面性能的仿真分析,结果表明采用此组合单元可有效拓展阵中单元及微带反射阵列天线系统的工作带宽.应用此组合单元法步骤简单,具有一定的通用性,可为各种反射阵列天线设计和工程实践参考.     

毫米波共形相控阵雷达导引头的阵列稀布优化

该文针对毫米波共形相控阵天线阵列稀布引起的栅瓣问题,提出了一种最优极化(交叉极化电平最小)条件下的阵列稀布优化准则。该方法首先建立毫米波共形相控阵雷达导引头极化辐射方向图的数学模型,通过对圆极化和线极化两种极化方式下交叉极化电平的比较,选取最优极化方式,选定阵列稀布优化的两组基本参数,然后利用改进的粒子群进化(MPSO)算法优化两组参数条件下的阵元分布,对比阵元分布优化后的天线方向图确定阵列稀布优化的基本准则,来有效抑制由于阵列单元稀布而引发的栅瓣效应。仿真试验证明该准则的合理性。     

L频段共形相控阵天线研制

为满足机载系统的需要,给出了共形相控阵天线的分析和设计过程,同时研制了一种高度仅为0.14波长的准八木天线单元。利用三维电磁仿真软件HFSS对天线单元和共形相控阵进行了仿真设计,并研制了一套L频段共形相控阵天线。该天线由天线阵面、波束形成网络和波控器等构成。天线阵面由4个天线单元组成,共形安装在机头上。经实际测试,共形相控阵天线阵面的和波束在扫描范围内增益大于10 dBi,并具有较低的副瓣电平;差波束零深小于-20 dB。     

The RCS of a cylindrical array antenna coated with a dielectric layer

The scattering properties of dielectric coated waveguide aperture antennas mounted on circular cylinders are investigated. Both the single element antenna and the array case are treated. The array antenna consists of 4 /spl times/ 32 rectangular apertures placed in a rectangular grid on the surface of an infinitely long circular cylinder. The problem is formulated in terms of an integral equation for the aperture fields which is solved with the method of moments using rectangular waveguide modes as basis and test functions. An efficient uniform asymptotic technique is used to calculate the excitation vector and the backscattered far-field. The asymptotic solution is valid for large cylinders coated with thin dielectric layers away from the paraxial (i.e. near axial) region. A similar asymptotic solution is used to calculate the mutual coupling in the nonparaxial region. For the self coupling terms and for the mutual coupling in the paraxial region a planar approximation is used with a corresponding spectral domain technique. Numerical results are presented as a function of frequency, angle of incidence, cylinder radius, and electrical thickness of the coating.     

Circularly polarized dielectric-loaded planar antenna excited bythe parallel feeding waveguide network

A new receiving planar array antenna for DBS (direct broadcasting satellite) is proposed. The element antenna is a short waveguide aperture mounted in the ground plane, loaded with a dielectric and polarizers, and excited through its side wall by another feeding rectangular waveguide. The gain of the element antenna loaded with a dielectric is so high that the grating lobes can be reduced sufficiently even if the element spacing in the array is wider than the wavelength in free space. Therefore we can reduce the number of the array elements, and parallel feeding by the low loss waveguide network can be feasible to provide a planar array antenna. This paper describes the experimental results of several kinds of the circularly polarized dielectric-loaded element antennas and the planar antennas fed by the waveguide network. In the 12 GHz band the planar antenna with 64-element radiators has a maximum gain of 31.9 dBi with an aperture efficiency of 94.7%, the 1 dB-down frequency bandwidth of the gain is about 800 MHz (6.7% for a center frequency of 11.85 GHz), and the frequency bandwidth of the axial ratio is less than 1 dB of 850 MHz (7.2%)     

An improved solution for integrated array optics in quasi-opticalmm and submm receivers: the hybrid antenna

A dielectric lens antenna that is a special case of an extended hemispherical dielectric lens and is operated in the diffraction-limited regime is considered. The dielectric lens antenna is fed by a planar antenna that is mounted on the flat side of the dielectric lens antenna, using it as a substrate, and the combination is termed a hybrid antenna. Beam pattern and aperture efficiency measurements were made at millimeter and submillimeter wavelengths as a function of the extension of the hemispherical lens and of lens size. An optimum extension distance for which excellent beam patterns and simultaneously high aperture efficiencies can be achieved is found experimentally and numerically. At 115 GHz the aperture efficiency was measured to be (76±6)% for a diffraction-limited beam with sidelobes below -17 dB. Results for a single hybrid antenna with an integrated superconductor-insulator-superconductor (SIS) detector and a broadband matching structure at submillimeter wavelengths are presented. The hybrid antenna is space efficient in an array due to its high aperture efficiency, and is easily mass produced, thus being well suited for focal plane heterodyne receiver arrays     

Reactively Steered Ring Antenna Array for Automotive Application

A novel type of smart antenna, called a reactively steered ring antenna array (RSRAA), is proposed. The antenna features a conformal configuration with three overlapping one-wavelength ring elements. Directivity can be controlled by changing the values of variable reactance circuits that are embedded in the antenna. The antenna can be mounted on the windshield of an automobile without interfering with the view of the driver. An equivalent model of six dipole elements is derived from the original antenna configuration to enable simple calculation of directivity when a set of reactance values is given. The validity of the proposed equivalent model is confirmed by comparing simulation results calculated by the equivalent model and by the method of moments. Another simulation shows that the conventional reactance domain multiple signal classification algorithm can be applied to the proposed antenna while keeping the estimated direction-of-arrival number equal to the number of reactance circuits. In addition, the characteristics of an RSRAA, which is optimized at 2.4 GHz and is mounted on an automobile, are measured in an anechoic chamber, and directivity control is found to be implemented effectively.     

Far-field pattern analysis of 94 GHz extended hemispherical lens monopulse antennas

In this paper, the far-field patterns are investigated for double-slot antenna array placed on extended hemispherical lenses. The radiation patterns of the extended hemispherical lens fed by single double-slot antenna or double-slot antenna array are computed using ray-tracing inside the dielectric lens and electric and magnetic field integration on the spherical dielectric surface. The computation results show that the sharp null of the difference pattern is below -37dB.     

新型弹载毫米波微带天线阵的设计

本文利用CST 电磁仿真软件进行设计了一种工作于35GHz 的弹载圆柱共形2X8 微带天线阵列,其在? 50mm ×50mm 共形表面布局6 个同结构的阵列天线,采用分时工作的方式,增大了探测距离,并通过改进阵列排列形式增 加了波瓣宽度。并讨论了平面与共形、改进的阵列排列以及不同圆柱半径对共形天线阵列辐射性能的影响。     

Multi-beam switched parasitic antenna embedded in dielectric forwireless communications systems

A nine monopole antenna embedded in a dielectric cylinder mounted on a small ground plane has been designed for IEEE 802.11 applications. Two simultaneous beams are controlled electronically with a front-to-back ratio of 12 dB and 13% bandwidth. The dielectric reduced the footprint by 85% and the antenna volume by 91% compared to an array with similar functionality in air     

一种小型化弹载共形天线的设计

精确制导导弹的隐蔽性以及抗干扰特性对弹载天线的带宽提出了更高的要求,而且在安装空间受限的弹载应用场合,弹载天线必须具有较低的剖面高度才能保证导弹的气动外形及飞行性能,因此,性能优越的超宽带天线以及共形天线成为重要的研究方向。文章以圆台形金属弹体为载体,设计了对数周期天线以及小型化改进的对数周期天线共形于圆台金属弹体表面,并能够组成六元天线阵列。仿真与实验测试结果说明了该设计的合理性。