An Equivalent Circuit for a Linear Oscillating Antenna Immersed in an Environment with Time-Varying Conductivity

In summary, it has been demonstrated that an equivalent circuit treatment of antenna response (including resonant behavior) gives reliable results, even when the ambient medium is characterized by time-varying conductivity. The equivalent circuit analysis has been verified by comparison with experimental data and with finite-difference calculations in which the fields are followed in detail. These comparisons have been made at peak conductivities up to 10-3 mho/m (well beyond the "man-survivability" level). Although the verification reported here has been limited to linear antennas, the equivalent-circuit approach is of much greater generality, and is currently being extended to inductively and capacitively-loaded antennas and loop and helix antennas. The development of antenna equivalent circuits is useful for at least two reasons--(1) it (2) it provides a natural way to introduce an SREMP-coupled signal into a network code for vulnerability assessment of a piece of electronic hardware. The antenna equivalent circuit simply appears as an extension of the system circuit.