平面三角形单极子天线展宽带宽研究

介绍了一种利用变形地板来展宽平面三角形单极子天线带宽的方法。通过在天线地板上刻蚀对称的变型L型缝隙,天线的阻抗带宽增加到2.5~10.8 GHz,带内驻波比(VSWR)＜2。对比没有刻蚀缝隙的天线,不仅工作频带得到展宽,而且保持了较好的辐射性能。测量和仿真结果表明,天线的工作频带能够覆盖整个超宽带(UWB)范围。     

利用接地板开槽减缩微带贴片天线的RCS

接地板开槽可以改变微带天线的辐射特性及阻抗特性,在微带贴片天线的频带展宽中已有所应用。该文给出了微带贴片天线散射特性的矩量法求解过程,并分析了接地板开槽对天线雷达截面(RCS)的影响。与短路针加载相结合,给出了一种接地板开槽形式。结果表明,据此设计的微带贴片天线在较宽频带内实现了RCS的减缩,同时天线的辐射性能保持良好,对天线的隐身有一定的借鉴作用。     

Development of PSO-ANN Ensemble Hybrid Algorithm and Its Application in Compact Crown Circular Fractal Patch Antenna Design

The traditional methods of designing antennas are not suitable in case of fractal antennas due to non availability of accurate mathematical design expressions. Recently, ANN model relating the physical and electromagnetic parameters of the fractal antenna to be designed is used as objective function of the optimization algorithm and it has been shown as an effective approach. In presented paper, ANN ensemble model has been used as the objective function of a PSO algorithm to calculate the optimal dimensions of a circular fractal antenna for desired resonant frequency. It has been established that ANN ensemble has better performance than the constituent ANN models. The design accuracy of the proposed hybrid algorithm is validated through the simulation and experimental results of the designed antenna. The size reduction capability of the proposed fractal antenna is used to design an antenna for 5.8 GHz WLAN band with a size reduction of 41.64% compared to simple circular microstrip antenna. The miniaturization of the antenna will lead to the design of compact devices for wireless communication systems.     

小型圆形贴片谐振器宽带带通滤波器设计

提出了一种频率在3.1~6.5GHz范围内的新型小型宽带带通滤波器。该滤波器结合圆形贴片谐振器的多模特性,通过引入输入端和输出端之间的耦合,增加了传输零点。通过三维仿真软件Ansoft HFSS中建模并优化,实现了通带内抑制在-20dB以下,低频段在1.9GHz处产生一个传输零点,高频段在7.6GHz处产生一个传输零点,带外抑制在-20dB以下。实测滤波器的结果与仿真结果基本一致,验证了设计的有效性。     

Koch分形与H形开槽相结合减缩微带贴片天线RCS

文中首次将Koch分形与H形开槽相结合应用于微带贴片天线RCS减缩中.设计了一副分形开槽微带天线.与工作在同一频率的矩形微带天线进行了比较,天线增益损失只有0.8 dBi,而天线的谐振峰值却得到了有效控制,天线RCS在带内减缩1.8 dBsm,在带外实现2 dBsm-14 dBsm的RCS减缩.设计天线具有较好的辐射特性和散射特性.     

宽带宽方向双倒F 振子天线设计

本文采用双倒F 振子天线（DIFA）结构设计一种宽带宽方向图天线。双倒F 振子天线不但具有单倒F 振子天线低轮廓、宽波束优点,还具有较宽的阻抗带宽特性。实测显示单元双倒F 振子天线在驻波比小于1.8 的情况下,阻抗带宽大于25%,在0°±85°区域内天线方向图增益≥-2dB。     

Design of a Compact Millimeter-Wave Microstrip Antenna with Wide Bandwidth and Broad Beamwidth

Design of a novel compact millimeter-wave microstrip antenna with wide bandwidth and broad beamwidth is presented. In the structure, multiple layers and a parasitic element as well as a coupling aperture are used to achieve wideband, while a conducting cylinder and the coupling aperture are used to obtain broad beamwidth. Finally, phased array with eight present elements has been designed as an example. Compared to traditional microstrip antennas and arrays, present antenna and array are of smaller dimension and broader beamwidth as well as wider bandwidth.     

圆形波导中线天线的辐射和互阻抗＊

本文采用并矢格林函数,场量变换和反应原理讨论了圆形波导中线天线的辐射和互耦合,给出了场强和互阻抗的普遍公式。波导是半无限长的,端面反射系数为Γ.天线的长度、馈电点和它们在波导中的位置都是任意的。作为例子,我们给出了四种特殊情况下的互阻抗公式,并进行了讨论。     

阻抗加载对微带天线辐射和散射的影响

计算了阻抗加载对微带天线RCS的影响，以及加载不同阻抗时天线的辐射性能。结果表明，阻抗加载主要降低天线带内RCS。适当的阻抗加载能有效降低天线RCS，同时还能保证天线的辐射性能。     

实用套筒天线宽带特性研究

本文采用Fourier变换的方法,给出了分析套筒天线的通用程序;系统研究了各参变量对天线阻抗特性的影响并给出了相应的曲线。在此基础上,总结出一种行之有效的理论设计和实验调整方法并利用此法设计了实用的工作于40MHz～88MHz的套筒天线。理论结果与实验测试相吻合。     

Design and Analysis of a Compact Dual-Band Serpentine-Shaped Patch Antenna with Folded Stub Lines for C- and X-Band Applications

Journal of Communications Technology and Electronics - Abstract—Antenna miniaturization plays an important role in modern wireless communication and has got some serious limitations. Gain and...     

一种基于FDTD的简单有效的天线阻抗计算方法

本文从有源区的软激励时Yee差分方程出发,推导了一种适用于理想的间隙激励(δ-gap source)和探针激励的天线输入阻抗新的计算公式,该方法简洁、有效,公式物理意义明确,能够有效地消除硬激励(hard source).计算天线阻抗时,在频率很低接近零时阻抗值的严重失真,使得应用时域有限差分法计算天线输入阻抗变得更加快捷适用.最后,本文应用该方法分别计算了一个单极子天线和同轴馈电的微带天线,单极子天线的计算结果和前人的计算结果吻合得很好,并且消除了频率接近零时以前计算结果的严重失真,微带天线和已有软件的计算结果进行了比较,得到了满意的结果.     

Synthesis of Combined Radiating and Filtering Structures Based on a Symmetric Slot Transmission Line

A model of a travelling wave printed slot antenna based on a symmetrical slot transmission line is considered. It is shown that a longitudinal segmentation allows to develop an analytical method of synthesis in the frequency domain, based on the approaches of smooth irregular transmission lines theory. A general method of synthesis is presented, and its specific features related to the slot line characteristics and an unknown distribution of the propagation constant are addressed. Method approbation was successfully demonstrated by synthesis of ultra-wideband structures with predetermined rejection bands.     

波导缝隙阵天线的电磁散射特性分析与校验

本文提出利用矩量法和等效边缘电磁流方法混合研究波导馈电的缝隙阵天线的频率响应和散射问题 ,得到数值结果 .分析了基函数的确定法则和波导缝隙阵天线的频率特性的决定因素 ,确定了计算波导缝隙阵天线散射特性时波导的作用是不可忽略的 .通过实验校验 ,分析了理论计算的误差来源 ,充分证实了本文方法的有效性和准确性     

双极化微带天线单元及二元阵的FDTD法分析

本文用FDTD全波分析法研究了双极化方形贴片单元的物理参数,即馈线宽度、相对介电常数和基片厚度对天线谐振频率、反射系数和隔离度的影响.比较了这些参数对二元阵和单元性能影响的不同,同时研究了阵列互耦随天线参数的变化情况.     

腔体内单极天线的电流分布及输入阻抗的研究

本文利用矩量法与并矢格林函数相结合,研究了腔体内单极天线(或探针)的电流分布及输入阻抗。通过选择分段正弦基函数,不但使矩阵阶数大大减小,而且改善了矩阵元素级数的收敛性。本文的数值结果还给出了腔体内有耗介质对输入阻抗的影响。     

Influence of Inhomogeneities in a Stratified Ground on the Field of a Circular Loop Antenna

This paper extends earlier works on three-dimensional scattering from a finite obstacle in a stratified halfspace, treated by means of the T-matrix method. In this paper we consider a general source configuration above the ground, that excites the subsurface medium and its inhomogeneity. Explicit expressions are given for the magnetic dipole, the circular, and rectangular antenna loops. Numerical examples, which show the effect of an extended source on the ground, are given for the circular antenna loop.     

Application of Sampling Theorem to the Synthesis of Transmission Line Tapers and Antenna Radiation Patterns (Correspondence)

In this note it is demonstrated how the sampling theorem may be used to reduce the problems of transmission line taper synthesis and antenna aperture field synthesis to that of optimizing a polynomial. In both cases the problem may be stated mathematically in the following form: find the function g(x) which is zero outside the domain - /spl pi//spl les/x/spl les//spl pi/ that will yield a desired f(u) where f(u) is given by the fourier transform of g(x).