An Ultrawideband Antipodal Vivaldi Antenna for borehole radar application

An Ultrawideband Antipodal Vivaldi Antenna with compact structure for borehole radar application is reported in this paper. The antenna is embedded in a cylindrical fiber-reinforced plastic (FRP) structure, operating in the frequency range from 600 MHz to more than 4 GHz. A metal reflector is attached to the cylindrical FRP to improve the direction of the antenna especially in low frequency. The simulation results show that good radiation patterns with direction of 4.6–8.7 dBi in end-fire direction is achieved in the whole working band, which indicates that the proposed antenna is suitable for directional borehole radar system.