Computation of Electromagnetic Fields Inside Strongly Inhomogeneous Objects Usingthe Weak Conjugate Gradient FFT Method

摘要

The computation of the electromagnetic field inside a strongly inhomogeneousdielectric object is formulated in terms of a domain-integral equation over the object. A weak form of the integral equation is discussed, in which the spatial derivatives are integrated analytically. Doing so, we obtain an equation that is solved very efficiently using the advantageous combination of a conjugate gradient iterative method and a fast Fourier technique (FFT). Numerical computations have been carried out for a strongly inhomogeneous lossy sphere. The incident field is generated by a 1/2 wavelength thin-wire dipole. Subsequently, the absorbed power density inside a CAT-scan generated model of the human body is computed. It demonstrates that the weak form of the conjugate-gradient FFT method can be considered as a comparatively simple and efficient tool for solving realistic electromagnetic wave-field problems.