Effective reconstruction of small dielectric objects in microwave imaging

Permittivity reconstruction of dielectric objects using gradient methods involves optimization where the object of interest as well as the background solution is optimized. But, when the object size is becoming smaller than the background size, the error in reconstruction has been found to be increasing. In this paper, the problem of reconstructing the small dielectric objects has been overcome by considering geometrical features of dielectric objects prior to optimization procedure. Linear Sampling Method(LSM) has been adopted to retrieve the geometrical features of the object and then the Conjugate Gradient(CG) method is applied to find the optimized electrical properties of the object. Numerical results have been discussed for different object sizes.