Design of exponential gradient TEM horn antenna for ground penetrating radar

Ground Penetrating Radar (GPR) technology is a kind of Ultra-wideband technology for underground targets. In this paper, an ultra-wideband transverse electromagnetic wave (TEM) horn antenna is designed. The size of this antenna is effectively reduced by adopting an exponentially graded horn structure, composite loading. Adding a metal reflector near the feeder further improves the antenna radiation directivity. The simulation results show that the designed antenna size is 0.50mx0.49mx0.33m (0.21x0.20x0.13 lambda). In the range of 0.125 similar to 3.1GHz, the voltage standing wave ratio is below 2, and the bandwidth ratio is 24.8:1. The gain is higher than 11.2dB above 1GHz.