A quadratic inverse model for RF tomography

The linear model provided by the Born approximation is frequently exploited in inverse scattering problems. Anyway, the limits of validity of the Born model can be extended by a quadratic approximation of the non-linear operator relating the scattered field data to the unknown object function. The aim of this contribution is to present a quadratic approach and describe its experimental validation regarding laboratory tests carried out in the case of dielectric objects. The results of the quadratic inverse approach are compared to the ones of the linear Born model; such a comparison highlights that the quadratic model yields superior reconstruction performance in terms of image focusing and artifact mitigation.