裹冰对垂直极化单偶极子天线性能的影响分析

严寒冬季,高山广播电视转播台天馈线系统被冰雪包裹之后,造成天馈线系统驻波比（WSVR）变大,反射功率增加,最终导致发射机保护停播。本文就襄冰对垂直极化单偶极子天线性能的影响进行深入的研究分析,并提出解决办法。     

调频广播发射天线改为垂直极化的讨论

引言在当今科学技术条件下,广播电台的广播信号的传播形式多种多样,但主要仍是依靠发射电波。在覆盖服务区内,受众不受地点、气候、设施等条件限制,可灵便、轻巧地从随身携带的收音机或车载收音机获得广播信息。这也是目前广播独有的优势。因此,广播电台除了要办好节目外     

改善偶极子板天线水平场形的方法

1引言偶极子板电视发射天线频带范围宽、增益高、结构简单。江苏如东电视台,有三个频道采用这种天线,各频道天线的配置方式相同,均取正置、等功率90“相位馈电。一般说来电视发射天线的水平场形应基本满足特定服务区域的需要,问题是特定服务区域的地形一般并不规则,电视发射塔也不恰巧就建在服务区的中心位置上,如东地处平原地带,东西长、南北窄,电视塔的位置偏东,如图1所示。对于特定的服务区天馈线应有特定的配置方式,如何使如东电视台九频道偶极子板天线的水平场形与地形基本吻合,从而使天线有较高的辐射效率,本文将就这个问…     

在发射塔顶加桅杆安装垂直极化天线的实践

目前广播电台是以发射电波覆盖服务区为主,而随着无线发射广播节目套数的增多,若采用多工发射方式,则因原有的天馈系统容量偏小而需更换,使费用大大增加;若安装一套新的天线系统,则因现有的发射塔已挂满天线而无空余位置.通过对多种方案的可行性进行对比研究后,我们采用在现有发射塔顶部加装10m高桅杆挂装垂直极化天线的方案,取得了良好的效果.     

飞机V形尾翼共形垂直极化合成天线

共形天线因其低剖面特性被广泛应用于现代飞行器中,垂直极化天线也是现代通信系统中最为简单经济的天线形式.基于目前天线设计中少有通过极化合成实现垂直极化特性的方法,提出一种与V形尾翼共形且具有垂直极化特性的合成天线,给出了以对称振子为合成单元的闭环解析公式,该公式可应用于任何角度、任何距离、任何激励的天线组合形式.通过HF...     

一种新型偶极子刀形机载天线

一般的偶极子天线频带比较窄,应用非常局限。本文在利用偶极子特性的基础上,结合工程实际,设计出了一种新型的平面印刷领结偶极子天线。通过实际测试,显示该天线在展宽后的频带上增益较高,可以承受大功率,工程实用性强。     

折叠偶极子天线的设计

射频识别(RFID)应用中的天线设计需考虑的最重要因素是低价位、小剖面和小型化,而为了最大功率传输,天线的输出阻抗必须和其后的芯片的输入阻抗匹配。本文介绍一种新颖的简单结构折叠偶极子天线,所需的输入阻抗能通过选择合适的几何参数轻易获得,这对设计特殊阻抗的天线非常有用。     

偶极子分形天线的驻波特性

提出一种新型偶极子分形天线，给出该分形天线的驻波曲线，同时讨论自相似性与驻波频段的对应关系及该分形天线与其对应的偶极子天线的驻波变化关系。     

垂直极化天线和环天线对高仰角天波接收能力浅析

垂直极化天线和环天线均为短波通信的常用天线。在复杂地域进行短波通信时,为解决通信盲区问题,可采取高仰角天波传播。短波天线对高仰角天波的接收能力决定了通信质量。本文分别对垂直极化天线和环天线进行分析,比较其接收高仰角天波的能力。     

DAB单偶垂直极化天线

本文简要分析介绍DAB单偶垂直极化天线的制作,以及DAB单偶垂直极化天线的调试,天线系统指标VSWR≤1.05。     

一种X波段正交极化偶极子天线阵设计

为解决X波段机载雷达变极化速度较慢的问题,设计了一种可实现脉间变极化的偶极子天线阵.该天线阵采用正交排列薄片电偶极子阵元,并加装垂直贴片和反射板,通过同轴线耦合巴伦进行馈电.利用改造后的阵元组成了一个4×4的16元矩形栅格、矩形边界均匀平面正交极化天线阵,利用射频开关控制馈电线路实现快速变极化,通过高频结构仿真(HFS...     

Low Profile Miniaturized Planar Antenna With Omnidirectional Vertically Polarized Radiation

A novel miniaturized cavity-backed composite slot loop antenna (CBCSLA) with low profile and omnidirectional radiation similar to a short dipole is presented. The antenna displays vertical polarization while having less than lambda/100 dimension in height. The geometry of the antenna is inspired from a small magnetic loop which is realized using a slot configuration on metallic ground. Since a small slot loop antenna cannot be impedance matched, a composite geometry is devised that acts like as a small slot loop and can easily be impedance matched using this configuration. The diameter of the CBCSLA can be made as small as lambda/10 or smaller. The feeding mechanism is designed in a manner to create a circumferentially-constant current distribution around the composite loop while effectively matching to a 50 Omega coaxial feed from the antenna center. Additional methods are discussed to further enhance the bandwidth and achieve a dual-band response. The antennas are designed, fabricated, and measured. It is shown that despite their small lateral dimension and extremely small height, the miniaturized cavity-backed slot loop features extremely well input impedance match, uniform radiation pattern, low cross-polarization levels and expected gain.     

对数周期振子天线分析与设计

采用感应电动势法分析了对数周期振子天线,对对数周期振子天线的终端传输线影响进行了认真的研究,最后在保证电气指标最优的情况下,设计出结构尺寸最小化、强度最大化的终端短路对数周期振子天线.     

Analysis of Eccentered Dipole Antenna for Borehole Radar

A dipole antenna in a borehole may be placed away from the center of the borehole, and this eccentricity produces additional complicated electromagnetic fields, which may influence borehole radar signals. In this paper, we analyze an eccentric dipole antenna in a borehole for borehole radars. Our approach is an extended version of the pseudoanalytical formulation that was previously applied for analyzing an induction logging tool and a dielectric logging tool. The proposed equations are suitable for modeling the finite dipole antenna, utilizing a method-of-moments. The eccentricity of the radar sonde has two consequences. First, it modifies the antenna characteristics such as its impedance, and second, it changes the electromagnetic field inside the borehole, owing to the change of the structure of the cylindrical layers. These two changes are evaluated by the proposed algorithm and two types of experiments. The first one is a measurement of the input impedance of a monopole antenna which is in cylindrical layers on a ground plane in air. The second one is about the transmission between two antennas, one of which is eccentered in cylindrical layers. This experiment was done in granite at a field test site and on a ground plane in air. In the field experiments, we controlled the position of the radar sonde in a borehole and made the antenna eccentered artificially. We found that a 4-cm displacement resulted in changes of 4 dB in amplitude and 4 ns in time delay. Comparing the experimental and calculated data obtained by the present method shows the validity of the proposed analytical formulation.      

一种新型弹载偶极子天线分析与设计

给出了一种新型结构的弹载偶极子天线,采用基于自补结构的蛇形振子作为辐射器,并用矩量法对振子结构进行优化,采用简化形式的锥形BALUN以实现平衡馈电。测试结果表面该天线具有良好的E面全向特性和宽带特性。主要分析了该天线的辐射特性,最后给出并分析了实测数据。该天线具有结构紧凑、馈电简单、带宽较宽、易于制作等优点。     

超宽频带小尺寸对数周期偶极子天线设计分析

文章研究了超宽频带对数周期偶极子天线(LPDA)的结构,对15～110MHz超宽频带对数周期偶极子天线的尺寸参数进行了设计,根据设计分析,对于超短波波段超宽频带对数周期偶极子存在的天线纵向尺寸较大的问题对该天线纵向尺寸进行了设计创新,从而使天线在包括工作带宽、增益、方向图等电特性参数不变差的前提下使纵向尺寸设计值从29...     

短波双极天线应用方法研究

双极天线是一种常用的短波天线,该天线对不同来波方向的电磁波的接收具有方向性。在组网中存在多家电台时,很难保证所有电台的来波都有最佳的接收角度,从而导致通信质量下降。通过分析双极天线上电流(或场)与来波方向的关系,在求得该函数近似解的基础上,通过数学仿真,立足实际应用情况,探讨双极天线的另类架设方法,使得组网通信效果更佳。     

Design and Analysis of Circularly Polarized Dielectric Resonator Antenna

Wireless Personal Communications - The paper presents a novel method for the improvement in the bandwidths by mode merging of the circularly polarized dielectric resonator antenna (CPDRA). The...     

利用三角振子天线改善对数周期天线的低频性能

介绍三角振子天线在宽频带对数周期天线低频段的应用并用软件计算三角天线的输入阻抗,通过实测证明该方法是正确的。