一种低栅瓣大瞬时带宽相控阵天线的设计方法

宽带相控阵天线一般利用时延补偿技术来实现.首先分析了波束指向的偏移对相控阵天线带宽的限制.接着对子阵均匀划分、不均匀划分、部分相位加权等方法进行了全面分析和阐述.相位的确定是通过遗传算法实现的.证明了采用这些方法,阵列的栅瓣、波束指向偏移都有较大抑制,带宽相应增加,为宽带相控阵天线的设计提供了参考价值.     

基于不均匀超介质的宽带高增益天线研究

提出了一种由双层不均匀频率选择性表面(FSS)结构组成的领结型高增益天线,对其进行了仿真分析。结果显示该天线在不加外匹配网络情况下,|S11|≤–6 dB的阻抗带宽可达到72%,同时有很好的辐射方向图。与均匀频率选择性表面组成的天线相比较,该不均匀性天线带宽为均匀频率选择性表面组成的天线的1.5倍,并且仍然保持低轮廓。这种特性适用于点对点弱信号通信。     

非均匀天线组阵SUMPLE合成相位补偿及信号强度估计

SUMPLE相关算法是深空网天线组阵中信号合成最重要的方法之一.在对SUMPLE相关算法分析的基础上,将均匀天线阵SUMPLE相位漂移补偿方法推广到了非均匀天线阵.根据权值系数的计算方法,提出一种非均匀阵各天线信号强度的估计算法.理论分析与仿真结果表明,所推导的相位补偿方法能有效消除非均匀阵合成信号的相位漂移问题;所提出的天线信号强度估计方法具有较高的估计精度.进行补偿相位估计时,应对权值系数进行低通或卡尔曼滤波,以降低权值系数的随机噪声.     

光模数转换系统中幅度不均匀性的校正(本期优秀论文)

分析了采样时钟的幅度不均匀性对高速光模数转换系统性能的影响,提出了一种校正补偿采样时钟幅度不均匀性的方法.该方法通过对系统光采样时钟进行测量和数据处理,来获取校正因子序列,再用校正因子序列对采样结果进行补偿.对提出的方法进行了实验验证,结果表明:该方法可有效抑制了幅度不均匀性的影响,提高系统有效比特精度.     

测控天线射电星角度标校方法分析

通过对常见射电源辐射特性进行梳理,分析了星体角径、空域分布及天线口径对角度标校的影响,提出了确定目标星体中心点的天线扫描方法以及天线和差电轴不一致性补偿方法,利用最小二乘法完成角度轴系误差修正系数的解算,并采用不同频段、不同口径天线进行射电星无塔角度标校的测试验证,检验了该方法的适用性和有效性.     

大型反射面天线轨道不平度对指向精确度的影响

针对奇台110 m口径射电望远镜高指向精确度特点,在现有天线指向模型的基础上,推导了轨道误差源(轨道不平度)对指向精确度影响的关系模型。基于功率谱函数傅里叶级数系数归并法,建立了天线轨道不平度数学模型。针对国外某完全焊接式50 m天线,轨道水平度测量数据,通过实验数值仿真,采用查表法补偿轨道不平度造成的天线指向误差,使俯仰角误差精确度提高了1.5″,对高指向精确度天线实现的研究提供了有力支持。     

电视11频道双环天线的设计和调试

河南省周口地区广播局试制了安装在边宽50cm拉线塔上的四层四面组合的双环天线。该发射天线的功率增益约为9dB,驻波比1.1以内的频带宽度为23MHz。单元天线的驻波比1.1内的频带宽度达50MHz,占设计频率的20%以上。该天线使用两年来稳定可靠,效果良好。本文简单介绍圆环周长为1.2波长的双环天线的工程近似计算法,用支撑腿上的金属片补偿电容的频带展宽法,以及电缆变阻器采用一段容性电缆并终接半可变电容的补偿方法.文末还对天线的功率增益进行了粗略的讨论。     

电小天线传输线补偿电路的优化设计

本文研究一种电小天线的新型补偿电路,即用短路传输线与天线相并联的方式实现对电小天线的宽带匹配.给出了在满足电压驻波比的前提下,以提高天线效率为准则的优化设计方案.在将天线、补偿电路以及馈电线作为一个整体,从而计算出阻抗、驻波比、效率、增益等参数的基础上,对电路的补偿能力进行了详细的讨论.整个分析过程不涉及具体天线的结构,因而是研究电小天线补偿电路的一般方法.     

TM65 m天线基础和轨道沉降及对天线指向的影响

天马望远镜（简称TM65 m）所建地区属于软土层,为保证望远镜高指向精度,需要坚实的基础支撑高精度的方位轨道平面。2012年7月~2015年7月,基于精密水准测量系统,采用闭合法对基础沉降及轨道面精度共进行了11次测量。测量数据表明基础沉降逐渐趋于均匀沉降,轨道面均方根误差为0.47 mm。测量结果显示天线的基础沉降和轨道面高程随方位角的变化具有相关性,说明基础沉降直接影响了轨道面的精度。采用实验、仿真和理论相结合的方法分析轨道面不平度引起的天线方位轴在东西和南北方向的误差。首先,线性插值测量的轨道不平度数据,提取某方位角对应的天线方位滚轮6支点的高程,然后将高程差作为约束边界条件施加到有限元模型上,最终仿真分析获得不同方位角下方位轴的倾斜量。同时,利用安装在天线座架上的电子倾斜仪对轨道面不平度进行测量,建立了倾斜仪x和y向输出数据与方位轴倾斜及对应方位角的关系模型,经拟合计算得到方位轴的倾斜量随方位角的变化关系曲线。仿真和理论分析结果具有很好的一致性,轨道面不平度对指向精度的影响在4内,分析结果为天线指向模型修正提供了依据。     

微带串馈赋形波束阵列天线设计

利用阵列天线的不均匀性可以实现对辐射单元幅度和相位的控制以达到特殊波束赋形目的。传统设计中,基本没有考虑微带不连续性对微带传输线长度的影响。本文采用仿真方法获得了微带贴片单元的等效参数,综合考虑了微带不连续性对贴片单元长度以及贴片间传输线长度的影响,设计了双层X波段32元串馈矩形微带贴片阵列天线,实现了余割平方赋形波束。运用电磁仿真软件CST对该阵列天线进行仿真,制作了天线实物并进行了实验,结果与预期指标吻合较好。     

大型长波天线支撑塔对电气性能影响分析

大型长波天线通常需要多座高耸铁塔支撑,接地支撑塔及其纤绳对天线辐射性能有一定影响。传统分析方法为解析法,有一定局限性,无法计算局部结构变化对天线电气性能的影响。本文使用基于矩量法的FEKO软件对长波天线进行计算仿真,重点分析支撑塔及其纤绳接地/绝缘对天线电气性能的影响,通过计算分析得出,支撑塔及纤绳绝缘能有效地提高天线的有效高度,从而提高辐射效率,为长波天线工程实施起重要的指导作用。     

Compensation of irradiation in a wide frequency range

Variants of application of the compensation method in a wide frequency range are considered. The method enables one to reduce the irradiation of a human organism and create a low-intensity field region (dark spot) in the near zone of an antenna. Structures with identical antennas, antennas equally spaced from the compensation point, and antennas with planar reflectors are proposed and analyzed.     

超宽带脉冲天线的补偿技术研究

针对超宽带通信系统中脉冲信号传输保真度的问题, 分析了保真度与脉冲天线的相频特性、增益-频率特性的关系, 提出通过调整天线的增益特性来对信号在自由空间产生的传输损耗进行平衡补偿的技术.通过对一款高保真印刷半锥形单极天线(Half-Printed Tapered Monopole Antenna, Half-PTMA)增益-频率特性的仿真分析, 以及将此补偿技术应用到一款超宽带平面单极天线的设计改进, 改进后保真度提高了5%, 验证了文中补偿技术的有效性, 为超宽带脉冲天线的高保真设计提供了有价值的设计依据.     

Accurate DOA estimation using array antenna with arbitrary geometry

The so called universal steering vector (USV) whose locus is equivalent to the array element pattern is applied to the direction of arrival (DOA) estimation by multiple signal classification (MUSIC) algorithm. It is shown that if the USV which includes the effect of the mutual coupling between the array elements is used, the compensation for the received voltage to remove the effect of the mutual coupling is not required any more. The USV for array antennas with arbitrary geometry is derived and evaluated efficiently by using the method of moments (MoM) so that the DOA estimation can be performed accurately by using the array antenna with arbitrary geometry. Numerical examples of the DOA estimation by a dipole array antenna, and an antenna array composed of a monopole antenna and a planar inverted-F antenna (PIFA) mounted on a mobile handset are presented to demonstrate the effectiveness of the proposed method.     

Measurement and evaluation of multi-antenna handsets in indoormobile communication

A method for evaluating antenna diversity systems is presented with an example of a handset using up to four antennas in indoor mobile communication. The method includes a “two-at-a-time” measurement test setup that uses maximum likelihood estimation of the covariance matrix and compensation for the imperfect match, which typically occurs during the design and evaluation process for compact antennas. The diversity performance of the antenna system can be presented as an effective order of diversity, which is the equivalent number of equal power, uncorrelated diversity branches for the same diversity gain at a given probability     

Accurate boresight measurements of large antennas and radomes

A laser-mirror system incorporated into an antenna pattern range is capable of aligning the antenna tower to measure the radome boresight error of large antennas to within 0.1 mrad angular accuracy. The simplicity of the alignment system makes it relatively easy to position the antenna, with or without its radome to a preestablished mechanical reference plane. Hence, deflection of the antenna tower system due to different loadings can be determined which otherwise would be undetected with most range facilities.     

The Millimeter Wave Radiation of a Traveling Wave Sinusoidal Wire Antenna

In this paper, investigation of radiation properties of the traveling-wave sinusoidal wire antennas is extended to the millimeter-wave frequencies (Ka-band) for the antennas whose geometrical dimensions vary in a wide range. Far-field patterns and S-parameters of composed three antenna sets were measured. A mathematical model was constructed for the structure and a MATLAB code based on this theoretical approach was written to calculate patterns, phase and attenuation constants of all investigated antennas. Frequency characteristics and the relation of antenna dimensions with wave parameters were investigated. Measured and calculated patterns were also compared with the constructed far-field patterns obtained by MoM (method of moments) and the MoM current distributions were used to explain the loss mechanisms of antennas. A directive, undistorted and smooth radiation can be achieved only choosing small undulated antennas whose peak-to-peak amplitude to period ratio κ is smaller than 0.4 (κ?<?0.4). It is shown that wavelength of broadside radiation is not equal to antenna period for all antennas, except for very small undulated antennas (κ?<?0.2). This antenna type can be used as a frequency-scan antenna for millimeter wave radars.     

一种多塔中波天线的设计与仿真

占地面积大、征地成本高、场地限制不好布设等问题一直严重制约中波天线的建设。 为了减少中波天线占地面积,提高铁塔的利用率,对天线布局和天馈网络进行优化设计,研究双频共塔匹配网络、阻塞网络和共址多塔天线辐射特性,给出三塔六频率的解决方案。最后,通过仿真论证,给出对应的网络、天线几何结构和辐射性能参数。     

Design method of Yagi-Uda two-stacked circular loop array antennas

A design method which works as a single balanced feed antenna is presented for the Yagi-Uda two-stacked circular-loop array antenna. The antenna is analyzed with a theoretical model consisting of loop elements and feeder sections. The results are compared with experiments. By using the computed and measured antenna currents, the gain enhancement of the antenna is confirmed to be due to both the stacked-loop-array and endfire-array effects. A method of compensation for the reflection loss and a design procedure are discussed in detail. A graphical method is given to estimate the optimum size of the antenna without detailed numerical calculations, and the performance of the designed antenna is demonstrated by experiments. Experimental results are presented for several antennas arranged with different numbers of loops in the endfire and broadside directions