Minedetection using ground penetrating radar. Development of new antenna concepts
Publish date: 2001-01-01
Report number: FOI-R--0268--SE
Pages: 119
Written in: Swedish
Abstract
This report summarizes studies and development of conceivable antenna concepts for handheld and vehiclemounted mineradar systems. The study has concentrated on TEM-horns and dielectric rod antennas. Possibilities and limitations of TEM-horn antennas adapted for impulse radar are demonstrated. An antenna for impulse radar involves conflicting requirements of high momentary bandwidth, high antenna gain, small size, possible crossed transmitting and receiving antennas et cetera, and that considerable compromises has to be made. These compromises implies that it isn´t possible to simultaneously achieve high antenna gain and large bandwidth with a single small antenna. Measurements performed with a demonstrator antenna MPAX proved that the antenna can detect metallic mines, anti-tank mines and shrapnel, metal spheres and to some extent antipersonnel mines that are buried in sand and soil. In most applications of dielectric rod antennas these are used over a narrow frequency range. In mineradar applications a very broad frequency range is necessary. An important limiting factor for the bandwidth is the antenna feed. It is proved that in order to obtain a broadband antenna it is advantageous to keep the diameter of the antenna smaller than the diameter of the feeding waveguide. The numerical simulations as well as the experimental evaluation proved that the doublecone rod antenna yields better broadband properties (smaller back lobes, and back lobes that occurs at higher frequencies) than the simple rod antenna.