Numerical modeling of subsurface communication
Abstract
Techniques are described for numerical modeling of throughtheEarth communication. The basic problem considered is evaluation of the field at a surface or airborne station due to an antenna buried in the Earth. Equations are given for the field of a point source in a homogeneous or stratified earth. These expressions involve infinite integrals over wave number, sometimes known as Sommerfield integrals. Numerical techniques used for evaluating these integrals are outlined. The problem of determining the current on a real antenna in the Earth, including the effect of insulation, is considered. Results are included for the fields of a point source in homogeneous and stratified earths and the field of a finite insulated dipole. The results are for electromagnetic propagation in the ELFVLF range, but the codes also can address propagation problems at higher frequencies.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 February 1985
 Bibcode:
 1985STIN...8532249B
 Keywords:

 Antennas;
 Communication;
 Computerized Simulation;
 Electric Dipoles;
 Electromagnetic Radiation;
 Extremely Low Frequencies;
 Homogeneity;
 Magnetic Dipoles;
 Models;
 Numerical Analysis;
 Soils;
 Stratification;
 Very Low Frequencies;
 Wave Propagation;
 Antenna Design;
 Electromagnetic Wave Transmission;
 Communications and Radar