气象雷达原理与系统.pdf

气象雷达原理与系统 第三章 雷达天线及伺服系统 气象雷达原理与系统 电子工程学院 大气探测学院 主讲：何建新 3.1 天线的定义及作用 Functions of an Antenna 3.1 天线的定义及作用 Functions of an Antenna 天线：辐射或接收无线电波的装置 • The antenna is one of the most critical parts of a radar system. It performs the following essential functions: • It transfers the transmitter energy to signals in space with the required distribution and efficiency. This process is applied 天线作用:是自由空间传播和导行波（传输线）传播之间的 in an identical way on reception. 换能器。 • It ensures that the signal has the required pattern in space. Generally this has to be sufficiently narrow in azimuth to provide the required azimuth resolution and accuracy. 发射（辐射）:把高频交流电转换成空间传播的电磁波（能量 • It has to provide the required frequency of target position 集中到所要求方向的赋形波束内）。 updates. In the case of a mechanically scanned antenna this 接收 :辐射的反过程，将空间传播的电磁波转换成高频交流电 equate