CALCULATION OF ELECTROMAGNETIC ANOMALIES OF PERFECTLY CONDUCTING BODIES BY INTEGRAL-EQUATIONS

Two integral equations applicable to calculating electromagnetic anomalies caused by perfect conductor models are studied. First it is shown that Maue's magnetic field integral equation, originally presented for a whole space environment, is valid for conductors located in horizontally layered space. Structural information for the surrounding space is carried by Green's dyadic functions. Secondly, using the quasi-static approximation for a magnetic field in a free space, a simple static integral equation is derived, in which the scattered magnetic field is represented by fictitious magnetic surface charges distributed on the conductor. The integral equations are solved numerically by the method of moments. Numerical solutions converge with an increasing number of cells. However, an accurate solution requires a large number of cells. The static integral equation is used for calculating airborne electromagnetic anomalies. The effect of thickness and dip angle of the thick plate is considered.