On the electromagnetic field excitation of smoothly curved wires

A smoothly curved wire of arbitrary geometric form excited by an external electromagnetic field is considered. It has been shown that the exact mixed-potential integral equations (MPIE´s) for the induced current and scalar potential along the wire can approximately be reduced to a system of telegrapher equations for each Fourier mode. Corresponding frequency dependent transmission line per-unit length parameters, inductive and capacitive, now slowly depend on the length of the curve. As example the coupling of a plane wave to a vertical semi-elliptical loop above a perfectly conducting ground is considered. The result of the calculation is in a good agreement with NEC.