带反射板的阿基米德螺旋天线

本文用矩量法计算了带有反射板的互补式阿基米德螺旋天线。计算结果表明,这种天线在臂长为1.6λ时,有一带宽为1∶1.2,轴比小于3dB 的圆极化辐射波。天线的输入阻抗为一接近60πΩ的纯电阻,功率增益可达8.6dB,比不带反射板的螺旋天线提高约一倍。     

天线罩加载问题的矩量法仿真与计算

研究天线罩系统在各类飞行器上应用非常广泛.为了保护天线免受恶劣环境的损坏,克服天线辐射引起误差,根据RWG基矩量法(MOM),用计算机仿真分析了天线罩加载后整套天线系统的辐射性能.首先,从表面积分方程(SIE)出发,利用等效原理结合矩量法对目标进行了严格的理论建模,推导出适合编程求解的矩阵方程.通过数值仿真,证明了算法的有效性.最后分别分析了加载体、天线罩对天线辐射性能的影响,并计算了加载复杂模型时天线系统的辐射场分布.证明方法可以改善任意形状加载体对天线系统的辐射影响.     

半波振子天线矩量法的研究

矩量法是将连续方程离散为代数方程组的方法,此法对于求解微分方程和积分方程均适用,本文以半波振子天线为例,系统的阐述了半波振子天线的海伦积分方程的建立,利用矩量法求解海伦积分方程而得半波振子天线上的电流分布,已知电流分布求解半波振子天线在远区的电场表达式和方向图。     

基于PSO方法的智能天线广播波束赋形设计

研究智能天线性能优化问题,为了快速、准确的对智能天线广播波束设计,提出了一种矩量法和粒子群优化相结合的混合方法.采用基于RWG基函数的矩量法对TD-SCDMA板状振子型智能天线阵进行了全波分析,并使用粒子群优化方法设计了智能天线的波束形状.采用MOM全波分析方法作为优化过程的计算核,既考虑了阵列单元间的相互耦合,又考虑了天线的实际形状,综合出了TD-SCDMA智能天线阵列单元的激励幅度和相位.结果表明,混合方法结合天线单元间互耦能够快速、准确的计算出所需要的理想波束,新方法具有实用性,为波束赋形的工程设计提供了依据.     

基于HALLEN方程法的半波天线的参数计算

在现代电磁工程中,对于边界不复杂的问题,可用解析法得到精准解,但较复杂的边值问题用解析法不能得到解答,需要数值法。在此导出HALLEN方程法,用MATLAB软件实现,它能够非常接近解析值,说明其正确性。矩量法是求解电磁场边界值问题中一种行之有效的数值方法 ,利用矩量法将HALLEN法的积分方程化为差分方程,将积分方程中积分化为有限求和,从而建立代数方程组,用MATLAB编程进行数值计算和仿真。最后得出结论 ,矩量法分析能够接近其解析解,说明其正确性。     

车载天线系统的网格划分仿真算法

该文提出了一种基于矩量法的网格划分算法,按照一定的建模原则将天线、无天线的导体面、有天线的导体面分别划分为直导线线元、三角形面元、矩形面元。该算法结构简单,划分过程中的数据存储采用树形结构链表。最后给出了用这种算法获得网格的算例,并用矩量法进行计算,计算结果验证了该算法的正确性。     

混合算法分析卫星星体对导航天线辐射特性的影响

为了测试卫星星体对星载导航天线辐射特性的影响,对太阳翼展开状态下的导航天线进行了数值研究,提出了一种基于矩量法MOM及物理光学法PO的混合算法,将研究目标划分为MOM区及PO区,并进行网格剖分,计算出卫星星体对导航天线影响后的辐射特性,计算结果表明,卫星星体与星载导航天线之间的耦合作用会降低天线主瓣内的辐射增益;同时,考虑到卫星星体的电大尺寸,以金属平台附近的线天线为例,采用矩量法MOM及仿真软件FEKO验证了混合算法MOM-PO的正确性。     

一种相控阵天线REV幅相校正方法的仿真与实践

介绍了基于傅里叶分析的旋转矢量算法(REV),并将该算法应用于相控阵天线各单元的初始幅相误差校正,给出了它的仿真分析和工程实现方法。所使用的校正方法区别于以往采用的REV校正方法,利于减少校正天线对相控阵收发信号的影响。仿真结果显示,校正后各通道的相位和幅度与人为设置的相位、幅度只差一个常数,表明方法是有效的;通过实际测试,校正后的天线方向图与近场校正结果逼近,EIRP比校正前提高1.4dB以上,验证了校正方法的功能和性能。     

P 波段抛物柱面天线的矩量法分析

应用矩量法对波长为0. 70 m 的P 波段抛物柱面天线进行了分析和计算, 该天线的馈源由7 元半波振子阵列构成。分析了馈源阵列偏离抛物柱面焦线时对天线增益、输入阻抗等性能的影响。计算表明, 馈源阵列沿径向向内偏离焦线时, 主要对天线的前后比产生影响, 沿径向向外偏离焦线时,对天线的主瓣和前后比都产生影响。此时, 天线输入阻抗的变化比方向图的变化明显。同样, 馈源振子直径的变化对方向图的影响较小, 而对输入阻抗的影响则较大。还对天线的波束扫描进行了模拟。     

双组引向八木天线的设计

本文给出了一种新型水平极化宽波束八木天线的设计.首先优化单排引向器八木天线,然后,利用引向机理,给出呈一定夹角的双组引向器八木天线结构,实现更宽的E面宽波束.用矩量法进行模拟并进行实物测试,验证了设计的正确性.     

Analysis and design of a novel radial folded waveguide structure for a feeder of a planar radial line antenna

Transmission characteristics of a new type of radial folded waveguide structure, consisting of a bifurcating metal disc with finite thickness between lower and upper radial waveguides and placed unsymmetrically in the folded portion as a general case, are investigated theoretically using a mode matching technique. A novel technique is proposed in which step junctions included in the bifurcating metal disc between lower and upper radial waveguides play an essential role in minimizing reflections caused by finite thickness of the bifurcating metal disc as well as the unsymmetry at the folded region and hence, a complete power transmission is achieved. Based on numerical computations some practical structure which is applied as a feeder for a planar radial line radiating structure of a plasma generating device is designed and perfect matching performance is demonstrated. ©1999 John Wiley & Sons, Inc. Int J RF and Microwave CAE 9: 415–423, 1999     

一种新型3G系统超宽带室内双向天线研究

设计了一种用于第三代移动通信系统的新型室内双向天线。通过采用渐变球激励的形式,解决了环形天线平衡馈电和阻抗匹配的问题,在节省复杂匹配网络的同时得到了很宽的工作带宽,不需附加额外的匹配网络,天线电压驻波比小于1.5时,阻抗带宽达到100%。天线工作在800 MHz~2 500 MHz,低频段增益可达5 dBi,高频段增益可达8 dBi,满足2G和3G移动室内通信在商务写字楼和宾馆酒店走廊两侧覆盖要求,与现有采用全向天线覆盖的方法相比可有效降低室内移动通信网络的建设成本,提高整个通信网络的容量和质量。     

A band‐suppression UWB suspended planar antenna incorporating a slotted spiral resonator

A novel miniaturized planar inverted F‐L antenna assembly is considered for UWB radio operations. The antenna design utilizes the electromagnetic coupling between an air dielectric planar inverted‐F antenna (PIFA) and a parasitic planar inverted‐L (PIL) element, with broadband feeding from a rectangular plate. To improve the functionality of the channel, a simple notch filter has been introduced through a local modification to the broadband feed plate, this takes the form of a simple slotted rectangular spiral resonator which is etched directly onto the plate. This allows the proposed antenna to maintain its full band UWB coverage, with the HYPERLAN/2 band centered at 5.35 GHz to be effectively rejected over the sub‐band 5.15–5.725 GHz, without the need for substantial re‐optimization of its principal structure parameters. The impedance bandwidth operates over the full UWB band, with VSWR better than 2, this performance is not degraded by the presence of the band rejection. The observed gains, radiation patterns, and group delay confirm that the antenna has appropriate characteristics for short range wireless applications. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

基于双焦点设计的平面波束扫描透镜天线研究

为了提升平面透镜天线的扫描性能,以实现波束扫描或多波束应用,首先研究设计了单焦点平面透镜天线,针对单焦点平面透镜天线在大角度扫描时增益降低太快的问题,引入了反射阵和传统介质透镜的双焦点设计方法。基于阵列天线合成理论,计算了双焦点透镜天线的辐射特性。采用多层金属孔阵列单元,建模了平面透镜天线模型,仿真对比了单焦点透镜和双焦点透镜天线的扫描辐射特性。结果表明,在扫描范围（0°-27°）内,双焦点透镜天线的最低增益相对于单焦点透镜天线有明显提升,而且大角度扫描方向图形状也有改善,证明了双焦点的设计方法有效提升了平面透镜的扫描性能。     

一种新型光子晶体基底太赫兹天线设计

设计了一种新型光子晶体基底太赫兹天线,该天线采用光子晶体基板结构可以有效抑制表面波效应,增强向自由空间辐射的方向性,从而提高天线增益。使用Ansoft HFSS 13.0构建太赫兹光子晶体天线的物理模型并进行仿真,该天线工作频率为212 GHz,最大增益约为6.5 d B,并且具有小型化的特点。     

Analysis and design of a novel hat feed with narrow beamwidth for the Fresnel zone plate antenna

Conventional hat feeds have the best performance in very deep reflector antennas because of their wide beamwidth. They also have the advantage of being self‐supported. The disadvantage of this type of feed is its wide beamwidth. To solve this problem, a new hat feed is proposed that can be used as prime‐focus feed for Fresnel zone plate antennas. The novel design, called parabolic hat feed is achieved by appropriate shaping of the hat feed profile. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

A novel approach for electromagnetic inverse scattering of a two‐dimensional perfect electric conductor object

A two‐dimensional shape determination technique for a perfect electric conductor target using electromagnetic inverse scattering is presented. The proposed algorithm uses the scattered field pattern and an inverse scattering technique derived from Green's function to retrieve the geometry of an unknown target. This method uses the scattering field data over a band of observation points, which is synthesized using frequency domain “method of moment” computational technique. We have verified this algorithm with four different types of numerical examples.     

Analysis,modeling, and design of cascaded defected microstrip structure for planar circuits

In this article, two cascaded defected microstrip structures (CDMSs) are proposed to increase the effective inductance. So the cutoff frequencies of filters made by CDMSs can be controlled. The proposed CDMSs have wider stopband characteristic and sharper transition from passband to stopband than defected microstrip structure (DMS). To show the behavior variations of the effective inductance, the DMS and CDMSs have been analyzed, compared, and their design parameters are formulated. These parameters are necessary for a fast filter design procedure. Also, the models of DMS and CDMSs using the very simple lumped element forms are presented according to the physical parameters. The results of the proposed models have been compared with those obtained by full wave analysis. To verify the proposed DMS model, the comparison in response not only has been considered in amplitude but also in phase of all S‐parameters of proposed model and full wave analysis. It is obvious that the stopband is enhanced by periodically cascading the DMS. Surviving of EMC aspects between DMS, DGS, and CDMS is considered and compared. Finally, the theoretical results are validated by comparison with simulations of the structures and experimental results. The simulations from modeling results are found to be in good agreement with the full wave analysis and measurement results in the range of 0.5–35 GHz. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.     

Simple design of broadband circularly polarized two‐arm Archimedean spiral antenna

This article presents a broadband circularly polarized two‐arm Archimedean spiral antenna with a novel simple feeding method. Contrary to the conventional spiral antenna excited by a vertically or horizontally balun, the presented design is directly fed by a coxial cable with a planar feeding section optimized to provide a broadband input impedance matching. An antenna prototype has been fabricated and measured to validate the concept. Measured results of reflection coefficient and axial ratio show a good performance over a frequency range from 1.0 to 3.5 GHz, equivalent to ~111.1%. Within this band, the antenna prototype exhibits bidirectional radiation with broadside gain values of better than 3.6 dBic.     

平面电容传感器参数优化设计及实验

平面电容传感器的性能指标由结构参数决定,如何优化结构参数使传感器达到良好的性能是传感器设计的关键.基于三维有限元仿真模型,研究了感应面积一定的条件下,电极对数、电极宽度与间距比对传感器信号强度、灵敏度及穿透深度的影响.采用神经网络方法优化结构参数,在保证穿透深度的条件下,获得较好的信号强度.研制了不同结构参数的PCB型平面电容传感器,并将其用于介电材料检测,实验结果证明了传感器参数优化测量的有效性.