探地雷达阻性加载天线的应用研究

Analysis on resistive loaded antenna for GPR application

阻性加载技术可以有效拓展天线带宽、降低时域振铃.该文以双纽线构成平面印制天线的辐射臂,分析阻性加载对其频域和时域特性的影响.通过数值仿真,讨论了天线在两种阻性加载方式下阻抗带宽和时域波形的变化.设计了一款指数型微带转平行双线的巴伦,并对巴伦和天线进行了加工及测试.测量结果表明,天线时域波形拖尾振铃小于10%;在0.8～6GHz频带内,天线单元回波损耗小于-10dB.将天线与雷达收发系统集成后,进行地下目标探测实验.雷达探测结果成像清晰、浅层目标分辨率较高.该天线具有超宽带、低振铃、紧支撑等特点,可满足便携式探地雷达的工程化应用需求.

Resistive loading technology could effectively broaden the band of antenna and decreases the later-time ring.An antenna whose arms vary according to lemniscale function is designed,and the influences of resistive loading on the characteristics in both frequency and time domains are investigated.The variation of impedance bandwidth and radiated wave of the antenna related to two kinds of resistive loadings are researched by numerical simulation.An exponential type balun which consists of a microstrip to parallel strip transition is designed for feeding.The measured results of manufactured antenna show that the band of the antenna in which the return loss is less than-10 dB is 0.8-6GHz,and the later-time ring is small than 10 %.An experiment for detecting the buried targets underground is carried out using the integrated radar system.Experimental results demonstrates high resolution ratio especially for shallow targets.The antenna has the advantages of ultra-bandwidth,low later-time ring,and compact geometry,so it is suitable for the engineering application of the handheld GPR.