Phased array technology for GPR antenna design for near subsurface exploration

The geophysical explorations for near surface investigations for buried objects are carried out by ground penetrating radar (GPR) using sensors operating at radio and microwave frequencies. It is well realized that focused beaming from an antenna into subsurface yields high resolution (with improved illumination of the target area) and results in better delineation of the subsurface targets. ASTRON (the radio astronomy research center of the Netherlands) has been engaged in developing a new generation of all-sky, full sensitive, multibeam radio telescopes for astronomical research at radio frequencies. Using a highly sensitive tapered slot THEA antenna, measurement beams on the sky are electronically formed and steered as desired. Experimental data show great promise in detecting moving objects in the sky. The existing know-how of focused beaming using phased array technology developed at ASTRON could be extended for better illumination of non-moving subsurface objects for GPR investigations. Stacking (adding) of the data gathered using both the beam-forming transmitting and receiving GPR antennas would result in reduced surface clutter effects and in enhanced detection of the near surface targets. In this paper, the concept of phased array technology in a bistatic mode of operation for GPR application is described.