Scale model experiments to study low-frequency electromagnetic resolution of multiple conductors

Low-frequency analog modeling experiments were conducted to investigate the response of two vertical half-planes to the horizontal loop electromagnetic method. Both insulating and conducting environments are considered. Several characteristic profiles of in-phase and quadrature components caused by diffracting objects were obtained. The results include the following: (1) the response of closely spaced conducting scatterers can be discriminated only if their separation S⩾ the transmitter-receiver separation L; (2) the distance W between the two extreme zero crossovers of in-phase and quadrature components; (3) the quadrature profiles are more sensitive than in-phase curves in resolving the target conductors; (4) for S<0.5 L, much higher estimates of conductance and lower estimates of the depth than actual situations will be obtained if the data is interpreted with the conventional half-space phasor diagrams