高频地波雷达接收天线效率对回波信噪比的影响

针对高频地波雷达天线小型化过程中，天线效率降低使接收回波信噪比减小缺乏定量描述的问题。通过对高频频段外部大气噪声以及天线、传输线和接收机引入的内部噪声的分析，推导出了高频地波雷达接收天线效率与接收系统输出信噪比的关系式，并利用此关系式计算出了一定参数下不会降低雷达探测指标的效率范围．经过在以上效率范围内，使用低效率小型化接收天线实测的海洋回波谱，证实了其效率不影响雷达的探测指标．说明了本文得到的关系式的实用性，为高频地波雷达接收天线的小型化设计提供了理论依据．

The Effect on SNR of Received Signal by the Efficiency of the Receiving Antenna of High Frequency Surface Wave Radar

In order to solve the problem that antennas efficiency decrease,turning up during miniaturizing high frequency ground wave redar(HFGWR)'s antennas,makes the signal to noise(SNR) of received signals weaken,which is absent of quantitative analysis,this paper analyzed atmospheric radio noise,antenna internal noise,transmission line noise and receiver internal boise.Here we also developed the relation expression between the efficiency of HFGWR receiving antennas and the output SNR of receiving systems.By using such expression,this paper obtained the efficiency range,in which HFGWR's detected parameters are free of reduction under a certain condition.The sea echo spectrum received by the antenna holding its efficiency in that range indicates that efficiency decreasing doesn't affect the HFGWR's detected parameters.These results approved the application of the relation expression mentioned above and gave the theoretical support for the HFGWR's antennas miniaturization design.