Analysis on resistive loaded antenna for GPR application

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 0.8-6 GHz, 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.