The failure of far field electromagnetic theory to be completely useful as a technique for detection theory as applied to the detection of mines and non-metallic objects in soil leads to the idea that perhaps detection is a near field problem. By synthesizing a near field by driving appropriate antennas and using this synthesized near field in a detection system, then increased range and signal processing capability might be expected. The likely components of the near field that would be useful are quardupole and octopole radiation. Feasibility studies of the concept would include calculation and comparing scattering cross sections of typical targets by dipole, quadrupole, and octopole radiation, determination of the arrangement of elements of antennas designed for quadrupole and octopole radiation for maximum directivity and also determination of input impedances for the various antennas.
