6.2. History

Fratianni investigated the effect of iron cores on the receiving efficiency of VLF loop antennas, in air and underwater [Fratianni, 1950].

Rumsey and Weeks investigated electrically small, ferrite loaded loop antennas. Approximate formulas have been developed for the impedance, efficiency, and Q of electrically small, ferrite-loaded loop antennas. The formulas are based on an assumed knowledge of these parameters for the antenna without ferrite loading. Radiation resistance formulation is also given [Rumsey and Weeks, 1956].

Devore and Bohley investigated an analytical model of a class of electrically small multiturn loop antennas has been formulated and compared with experimental measurements over a frequency range of 3 to 86 MHz. Both air core and magnetically loaded cases were examined. The analytical model described in this paper should prove an effective design aid for a volumetrically constrained antenna of the class [Devore and Bohley, 1977].

Burton et. al. investigated the electromagnetic field of an electrically small loop antenna with a cylindrical core. The infinitely long cylinder may be conducting or insulating. With the help of the principle of similitude, measurements made with a small loop at a high frequency with cylinders of water with widely different conductivities are applied to a very large loop around a mountain at a very low frequency. An approximate equivalent circuit for the loop with a core is described and tested [Burton et. al., 1983].

The goal of this research is to develop and validate a low-frequency modeling code for high-moment transmitter rod antennas to aid in the design of future low-frequency TX antennas with high magnetic moments. modeling code can predict the TX antenna’s gain, maximum magnetic moment, saturation current, series inductance, and core series loss resistance, provided the user enters the corresponding complex permeability for the desired core magnetic flux density [Jordan et. al., 2009].