We present a solution of the inverse problem of reconstructing boundary deformations in a coaxial cylindrical waveguide by using a first order perturbation method applied to the dominant TEM-mode. We have applied and investigated different orders of Tikhonov regularization using the L-curve criterion. The reconstruction results from using reflection data are presented and they indicate an agreement between the reconstructed and true continuous functions that describe the deformations of the waveguide boundaries.
QC 20150521