Roving Sources, Simulation and Reciprocity

Detailed herein is a post-processing method for modeling the fields of a roving source in an inhomogeneous environment. The method invokes the reciprocity theorem and employs the concept of calibration length and area for the antennas of the problem space. Because the reciprocity theorem is a statement about projections, we show why six simulations are needed to obtain the six components of the electromagnetic field. Detailed FDTD simulations are conducted and validated by measured data, as obtained from several experiments conducted at Lake Pend Oreille, Idaho, USA. Other numerical methods (i.e., finite element, Sommerfeld full-wave, quasi-electrostatic) are also considered to provide additional validation. The problem is germane to naval applications, which justifies the use of extremely low frequencies in the experiment and simulations.