Series expansion of polarization currents for imaging of large dielectric cylinders

For the reconstruction of a large and high-contrast two-dimensional dielect ric object, an inversion algorithm is proposed where the polarisation curre nt inside the object is expanded in terms of Fourier series in the angular direction and eigenfunctions with orthogonality and completeness relations in the radical direction. By using this algorithm and a hybrid optimization algorithm combining the genetic algorithm and the Levenberg-Marquardt algo rithm, circular dielectric cylinders of a diameter of four wavelengths are reconstructed with multiple incidences of plane waves in the presence of 20 % Gaussian noise in the scattered fields. (C) 2000 John Wiley & Sons, Inc.