Seawater Antenna Range

Bradley Tarrant

Abstract


The aim of the sea water antenna range project is to develop and evaluate designs for an underwater antenna test range, comparing the range and data rate for a given water attenuation and operating frequency. This report begins by validating two separate theoretical models in order to calculate the magnetic field strength at some radial distance away from a time varying current distribution within a salt water medium. It proceeds to the development and characterisation of six loop antenna designs, with a single design chosen for the experimental application within a purpose built wooden tank filled with salt water. Comparisons between the normalised analytically calculated and experimentally measured results identify consistencies in the relationship, with similarities in spatial variations in each waveform for all tested frequencies.
Additional test case scenarios included determining the magnetic field strength attenuation rate by radially incrementing the antenna away from the current distribution for frequencies between 20 MHz to 100 MHz. The results concluded that the two theoretical models presented within this report are applicable for determining the magnetic field strength at any location away from a finite length current distribution within a salt water medium.

Keywords


Electromagnetics; seawater

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