Investigations of RL-Loaded Bowtie Antenna for Low-Resolution GPR

A resistively-inductively loaded (RL-loaded) bowtie antenna for impulse ground penetrating radar (GPR) is theoretically and experimentally investigated. The antenna has been designed for transmission of Gaussian-like pulses with duration of 6 ns (100 MHz central frequency). As ultra-wideband (UWB) antenna, it is suitable for low-resolution GPR that can be used in tunnel geology forecast. The simulating results and the Smith chart created by the network analyzer are analysed. We implement lumped resistor-inductance loading (RL-loading) to the antenna. Experimental results show that VSWR of the loaded antenna is less than 2.5 in the band 0-300 MHz while the transmission efficiency keeps unchanged basically after loading. The RL-loading raised in this paper makes the narrow pulse generator and the antenna-feed system get matched. Time-domain waveforms and radiation pattern of the antenna are shown in this paper.