Accession Number:

ADA123669

Title:

ULF Near Fields in Layered Media.

Descriptive Note:

Final technical rept. Nov 81-Nov 82,

Corporate Author:

PACIFIC-SIERRA RESEARCH CORP LOS ANGELES CA

Personal Author(s):

Report Date:

1982-10-01

Pagination or Media Count:

43.0

Abstract:

This report derives formulas for ULF near fields using a five-layer, stratified model of the earth-air-ionosphere system, and gives numerical results for a frequency of 0.1 Hz and ranges between 5 km and 5 Mm. It assumes a semi-infinite, finitely conducting ionosphere 50 km above a three-layer earth, comprising a moderately conductive overburden, a resistive layer, and a highly conductive mantle. It, therefore, accommodates the two-dimensional confinement of the fields between the earth and the ionosphere as well as possible waveguides in the resistive layer. However, it omits waves that might be guided in the ionospheric F-layer and ignores lateral variations in the earths conductivity. The ionosphere is found to influence the signal by causing its range dependence to change from inverse cube to inverse square beyond about 50 km. That result increases the maximum range predicted for ULF near-field communication systems. Author

Subject Categories:

  • Electrical and Electronic Equipment
  • Electricity and Magnetism
  • Radiofrequency Wave Propagation
  • Radio Communications

Distribution Statement:

APPROVED FOR PUBLIC RELEASE