HF Antenna Overview短波天线概述云南监测站业务室2011年 4月-2-Introdu ction介绍BlockDiagramofaRadiocommu nicationLink无线电通信连接框图Anantennaisanimportantelementin acommu nication,DF,monitoringormeasu rementsystem,likealinkofachain.天线在通信系统、测向系统、监测或测量系统中是一个关键的部分，它就像一个环路（把发射和接收连接起来）-3-TheR&Santennadepartmentisdeveloping,marketingandsellingantennasforvariousapplications.R&S公司的天线部正在开发和销售各种应用天线。AntennaDesignDependingonApplication天线的设计取决于我们的应用AntennaDesignDependingonOperationalFrequencyRange天线设计还取决于工作频率范围-4-Typesofwavepropagation:Groundwave,skywaveandfree-spacecommunication电磁波的传播类型：地波，天波和自由空间波Polarization and Antenna Pattern极化和天线方向图FundamentalsofWavePropagation电磁波传播基础PolarizationTypes极化方式-5-Linearpolarization:线极化Planewave平面波(Evectorvariesinamplitudeonly)电场矢量只在幅度上发生改变（电场方向不变）Sinusoidalshape正弦波形状Verticallypolarized/horizontallypolarized垂直极化/水平极化Easiestsolutionofthewaveequation最简单的电磁波方程解-6-Circular polarization圆极化Circularpolarization(RHCandLHC)圆极化（左旋极化和右旋极化）Specialcaseofellipticalpolarization圆极化是椭圆极化的特殊情况(Evectorvariesin amplitudeanddirection)电场矢量在幅度和方向上都发生改变Righthandcircular右旋极化Lefthandcircular左旋极化Source信号源-7-Loss by Polarization Mismatch极化方式不匹配引起的损耗Antennapolarization天线极化方式Evectorofincomingsignal来波信号的电场矢量方向Linearpolarizedantennascancovercircularpolarizedsignalswithreasonablelosses.线极化天线可以覆盖圆极化信号，但是会有一定的损耗。Circularpolarizedantennascancoverbothlinearplaneswithreasonablelosses.圆极化天线可以覆盖线极化信号，但是也会有一定的损耗。-8-Usage of Different Polarization不同极化方式的应使用Low frequencies (10 KHz to approx 5 MHz)低频（10 KHz 到约 5 MHz）Mainlyverticalpolarization(groundwavepropagation)在这个频率范围内主要采用垂直极化（地波传播）Middle and upp...
