螺旋天线的快速分析及宽带化设计

研究了一种快速计算螺旋天线电特性的新方法,并结合遗传算法对天线进行了宽带、小型化设计。采用直线段对法向模螺旋天线进行划分,应用合成基函数及合成检验函数的矩量法对阻抗矩阵进行了降阶处理,节省了求解矩阵方程所需的时间和存储量。结合遗传算法对加载法向模螺旋天线上的加载集总元件的值、加载位置以及匹配网络参数进行一体化优化设计,并采用Sherman-Morrison-Woodbury公式快速求解加载后的矩阵方程,提高了优化设计的效率。最后,成功设计了一副工作在100～1000MHz的宽带小型化螺旋天线。     

改进遗传算法对高频宽带加载天线的优化设计

按照某高频地波超视距雷达接收天线阵小型化的要求,在4～8MHz频带内,采用一种改进型遗传算法对高频宽带集中加载天线及其宽带匹配网络进行了优化设计.同时根据天线工程与实践,详细分析了集中加载元件值及加载位置扰动对天线电性能的影响,分析表明,优化设计得到的加载参数对优化不十分敏感.     

加载法向模螺旋天线的研究

采用矩量法分析了法向模螺旋天线加载后的电特性，探讨用加载来实现法向模螺旋天线宽带化小型化的可行性。计算时采用螺旋线段对天线进行划分，然后采用三角形基函数脉冲基检验的矩量法来快速精确计算天线上的电流分布，计算了一些加载螺旋天线的实例。并与直线段划分的矩量法的结果进行比较。最后借助遗传算法优化设计了一付工作在220-400MHz的法向模螺旋天线。     

加载技术在天线小型化设计中的研究

研究学习了加载技术及其与其他小型化、宽带化技术的组合应用,并介绍了加载的优化设计,通过最优化分析寻求加载的最优位置、加载形式、元件值,从而设计满足指标要求的宽带小型化天线。由于天线的方向系数、效率、带宽和体积尺寸等构成矛盾的关系,如何协调和折衷上述关系获得最佳天线结构,成为宽带小型化天线设计的核心问题。研究表明,将加载和其他技术的整合应用是未来天线设计的发展趋势。     

VHF/UHF天线宽带匹配网络的优化设计与实验研究

本文系统地研究了VHF/UHF天线宽带匹配网络的设计与制作.提出遗传算法与模拟退火法相结合的优化设计方法,解决VHF/UHF天线宽带匹配网络制作过程中元件值随频率较大变化引发的难题.最后,利用该方法研制了30~450MHz全向宽带小型化天线的宽带匹配网络.实验表明,带内VSWR＜3.0,且计算结果与测试结果十分吻合.     

一种短波宽带鞭天线的设计方法

设计了一种短波宽带鞭天线.为缩小天线尺寸和提高工作带宽, 采用集总元件和传输线, 运用加载技术和宽带匹配网络技术相结合提高了天线的宽频带特性, 基于矩量法分析仿真天线性能, 混合遗传算法和差分进化算法进行天线加载和匹配网络的一体化优化.根据综合出的天线参数实际制作了一副短波宽带鞭天线, 通过对比实测与仿真电压驻波比(voltage standing wave ratio, VSWR)曲线, 二者吻合较好, 验证了设计方法的正确性.     

复合加载平面螺旋天线的设计

介绍了一种复合加栽的背腔式平面螺旋天线。通过宽带天线加载减小传输段长度,锯齿加载增加螺旋曲线辐射段有效长度,降低腔体高度等方法,对背腔式平面螺旋天线各参数进行综合优化设计,实现了一种小型化、宽频带、复合加载平面螺旋天线。测量结果显示天线在带宽为5：1频率范围内保持了良好的辐射特性。     

VHF宽带小型化套筒天线的优化设计

研究了VHF宽带小型化套筒天线的设计与制作。采用遗传算法与模拟退火法相结合的优化方法，对套筒天线的结构参数以及宽带匹配网络的元件值进行一体化设计。分别采用外插收敛法、[Z]矩阵插值法以及小波变换法来提高矩量法分析计算天线的速度。利用该方法成功的设计了两副全向宽带小型化的套筒天线。     

基于遗传算法优化设计18：1宽带单极天线

基于矩量法理论,采用遗传算法对宽带集中加载单极天线进行了优化设计.根据优化的结果设计了一付天线,在30～540 MHz频率内VSWR<3.5,阻抗带宽达到18∶1,天线高度为1.6 m,适用于移动的载体多频段通信系统.实验结果表明,该方法是有效的和可行的.     

一种宽频带高稳定相位中心导航天线的设计

设计了一款基于阿基米德螺旋天线的宽频带高稳定相位中心导航天线.采用阿基米德螺旋天线结构实现了宽带驻波带宽和轴比带宽,结合三维扼流环结构改善了天线相位稳定度和多径抑制能力.通过有限元电磁仿真软件建立了仿真模型和完成了参数优化设计,所设计的宽带高稳定相位中心导航天线的指标达到:在GPS、北斗、GLONASS和Galileo卫星导航系统的所有工作频点上,输入端口驻波比均小于1.45;在俯仰角-60°~60°主波束范围内轴比小于3 dB,相位稳定度在-2.5°~2.5°,方向图增益均在5 dB以上.相比于未加载扼流环,所设计天线的增益前后比改善2~6 dB（仰角60°和仰角120°对应增益差值）.该研究表明,结合了三维扼流环结构的阿基米德螺旋天线综合性能优异,适于设计宽频带高稳定相位中心天线.     

Design of electrically loaded wire antennas using geneticalgorithms

A novel antenna design procedure based on genetic algorithm (GA) driven optimization is proposed and applied to the synthesis of wire antennas loaded with lumped components. Loading circuit parameters, locations of the loads along the antenna, as well as matching network parameters, are optimized simultaneously. A computational scheme based on the Sherman-Morrison-Woodbury formula for the fast evaluation of the antenna performance for many distinct loading configurations is developed. The GA iteratively guides a population of randomly selected design candidates toward the optimal solution. The success of the proposed procedure is demonstrated through its application to the design of efficient ultra-broadband antennas and their corresponding matching networks     

MAMA: a new methodically designed broadband microstrip antenna using off-the-shelf components

The current paper proposes a new, simple, methodical approach to broadband microstrip antenna design. The approach relies on a reformulation of the antenna-design problem as an impedance-matching problem, in which the antenna is considered to be the matching device required to match the feed line to air. Thus, impedance-matching techniques, such as Chebyshev transformers and a Klopfenstein taper, are employed to determine the antenna parameters necessary to satisfy a set of specifications. Simulation results as well as measured results show that the proposed matched-to-air microstrip antennas (MAMAs) qualify as a new class of broadband microstrip antennas, which have the advantages of relying on a systematic approach (as opposed to the usual trial-and-error procedures that are now prevalent), as well as being very easy to fabricate, using inexpensive off-shelf components.     

一种小型化超短波单极子天线设计

超短波天线在舰船飞机上应用很广,天线的小型化有利于提升其隐蔽性、稳固性,因此对天线的小型化设计显得异常重要。采用加载集总元件和宽带匹配网络的方式,设计了一款新型超短波天线。将宽带匹配网络做成一个微带电路结构与天线辐射单元直接相连的一体化设计,进一步减小了天线的长度;采用 Matlab 和 HFSS 软件联合仿真,并运用遗传算法优化计算全部集总元件的具体数值。天线在100 MHz~400 MHz频段范围内的驻波系数 VSWR(电压驻波比)小于3,水平方向全向辐射。天线和匹配网络总的物理长度仅为255 mm,实现了小型化的要求。制作了天线实物并测量,实测天线参数与仿真参数吻合较好,达到了设计目标。     

Investigation into Polarization of Unloaded and Loaded Microstrip Square-Ring Antennas

The polarization characteristic of unloaded and loaded square-ring microstrip antennas is investigated. Several different loading types like single-stub, dual-stub, notch, gap and shorting-pin are considered and their effects are studied. Loading enables feeding using a 50-Omega probe. The simulation and measurement results show that the loading techniques excite a loaded TMy ₁₁ mode that is orthogonal to the unloaded TMx ₁₁ mode. This indicates that by loading the ring antenna its polarization can be switched adaptively. However, the purity of the loaded and unloaded modes depends on the loading type. For some loading types like gap and shorting-pin, the excitation of the unloaded mode seems negligible, in comparison to the loadings by stub and notch. For the stub and notch loaded antennas the unloaded mode is also present, and its excitation efficiency is frequency dependent. Thus, their polarization plane, which is due to both loaded TMy ₁₁ and unloaded TMx ₁₁ modes, also becomes frequency dependant. The results of this investigation can be useful in selecting the loading methods for high-impedance microstrip ring antennas, and control of their impedance and polarization. The knowledge of the antenna polarization is essential in communications, and its dependence on the loading type can be used as an important parameter in design of adaptive antennas and sensors.     

岸基远程高频表面波雷达小型宽带天线系统的设计

从高频表面波雷达天线工程的角度出发,基于对数周期天线的设计理论,优化设计了一副小型 宽带发射天线;基于端射阵理论,优化设计了一副小型宽带、具有大前后比的双鞭天线,并以此作为阵列天线的基本单元组成六元均匀线阵。文中分析了收发天线的工作原理,并给出了计算机模拟结果。     

FDTD分析探地雷达天线的辐射特性

探地雷达系统一般采用超宽带短脉冲信号,因而其天线系统必须具有较好的宽带性能。只有几种类型的宽带天线能够用于探地雷达系统中,如电阻加载的蝶形天线、TEM喇叭天线及其变形形式。本文将给出一种新型的探地雷达天线,该天线为置于镜像面上且具有离散指数电阻加载的单偶极子。文中将采用FDTD计算和分析该天线在自由空间和有耗媒质上方时的辐射特性。结果表明,通过选择一定的电阻加载形式,可使天线具有较好的辐射波形,从而能够满足实际探地雷达的需要。最后,通过地下目标散射场的理论结果和实验结果说明了本文所采用方法的正确性。     

Circular polarised microstrip patch antennas for broadband and dual-band operation

A novel design of microstrip patch antennas for circular polarisation (CP) is proposed. As an example, two CP patch antennas are investigated: a broadband CP patch antenna and a dual-band CP patch antenna. The proposed structure can be achieved by embedding circular holes in the microstrip circular resonator. By changing the size and position of loaded holes, two orthogonal modes are simultaneously excited with equal amplitude and /spl plusmn/90/spl deg/ out of phase. Without any 90/spl deg/ phase-shifter, the proposed CP patch antennas are excited by single feed.     

Cylindrical transmitting antenna: Tapered resistivity and multiple impedance loadings

A general formulation is presented which treats with accuracy the perfectly conducting antenna, the uniformly resistive antenna, the tapered resistive antenna, and the multiple impedance loaded antenna. The current distribution is obtained in analytic form that is easily used to obtain the effective length and radiated field. The presented theory has application in traveling-wave antenna design. Traveling-wave antennas are of interest for broadband and directional communication. Extensive numerical results are obtained, and comparisons are made with experimental data. The results indicate the feasibility of cylindrical traveling-wave antennas.