Calculation of electromagnetic field components in frequency and time domain using dipole source excitation and layered earth model: Documentation of software development

The completely generalized program that calculates the mutual coupling ratios of two loops over an n-layer earth model in four coil configuration (horizontal coplanar, perpendicular, vertical coplanar and ver-tical coaxial) systems has been modified to take advantage of a digital linear filter method. This method rapidly evaluates the many Hankel transform integrals encountered in layered earth electromagnetic modelling. The program is valid for any frequency, coil separation or coil altitude and any resistivities, dielectric constants and relative magnetic permeabilities of the layers. Applying this rapid and thus inexpensive method it has also been possible to develop a computer program that calculates the time domain electromagnetic response of a multilayered earth for the Crone PEM dipole system. The conversion into the time domain involves Fourier series summation of the matched complex mutual coupling ratios of the layered earth models computed by the digital linear filter method.