Frequency-domain formulation for nonlinear method of moments

In this paper a frequency domain formulation of the method of moments taking into account the presence of ferromagnetic materials is presented. By combining the electric field definition, Ohm´s law and Lorentz gauge inside every volume element into which the system is subdivided, a linear algebraic system of integral equations is obtained. Considering the nonlinear constitutive equation H=H(B) and the magnetization M a nonlinear algebraic system of equations is obtained. The unknowns of these systems are the time Fourier transforms of magnetizations and conduction currents. The solution of these systems for a finite number of harmonics gives the frequency domain solution of the problem. The use of pulse functions as subsection bases allows a quick matrix set up especially when regular volume shapes are selected. Calculated results are compared with results obtained with other methods