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Finite-element techniques are applied to the frequency response computation of the input impedance of antennas with the eddy current losses taken into account. Both time-domain and frequency-domain approaches are discussed. Comparison to results for a dipole patch antenna with T-match obtained by assuming infinite conductivity is presented. [ABSTRACT FROM AUTHOR]

Different techniques are investigated to improve the performance of the solution process of 3-D, time-periodic, nonlinear, voltage-driven eddy current problems under the influence of dc bias by the means of the finite-element method. The underlying nonlinear iteration technique is the time-periodic fixed-point method. The benefit of a static approximation to generate an initial solution, i.e., of a static initialization is pointed out. A secant method and a Schur complement technique to carry out the static initialization are compared. The procedures developed are applied to 3-D models of one- and three-phase benchmark transformer problems with dc bias. [ABSTRACT FROM AUTHOR]

A finite element method for the analysis of three-phase, three-limb power transformers under dc bias is presented. The phase voltages and the dc components of the phase currents are assumed to be given. Using parallel algorithms, the steady-state periodic solution is obtained without stepping through the transients using a fixed-point method to solve the nonlinear equations. A novel technique to obtain the starting solution for the fixed-point iterations to ensure fast convergence is introduced. The solution to a large, real world problem is presented. [ABSTRACT FROM AUTHOR]