AN EXPERIMENTAL STUDY OF GROUND WAVE PROPAGATION ACROSS SEMI-INFINITE STRIPS AND ISLANDS.
COLORADO UNIV BOULDER DEPT OF ELECTRICAL ENGINEERING
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Experimental amplitude and phase measurements of electromagnetic ground wave propagation across semi-infinite strips and islands were conducted for normal incidences. Models for propagation were used with aluminum plates simulating highly conducting media and water simulating imperfectly conducting media. The frequency used was 4.2937 Gcs. An open-end waveguide located at the water surface and a small switching dipole were used as the transmitting and receiving antennas, respectively. Both amplitude and phase measurements were made by using a modulated scattering dipole technique. The theoretical formulation for normal incidence very low frequency VLF ground wave propagation across a simple mixed path was developed by J. R. Wait, using a perturbation technique. Waits work was extended to semi-infinite strips and islands by R. J. King who used an equiavalent formulation in an elliptic coordinate system. In both formulations, an approximate solution for the forund wave attenuation function was obtained. Computer methods were used by King for numerical calculations. The experimental data obtained verified the theoretical calculations and also substantiated the limitations of theory implied in the formulation. Author
- Radiofrequency Wave Propagation