Physics-Inspired Convolutional Neural Network for Solving Full-Wave Inverse Scattering Problems

In this paper, to bridge the gap between physical knowledge and learning approaches, we propose an induced current learning method (ICLM) by incorporating merits in traditional iterative algorithms into the architecture of convolutional neural network (CNN). The main contributions of the proposed method are threefold. First, to the best of our knowledge, it is the first time that the contrast source is learned to solve full-wave inverse scattering problems (ISPs). Second, inspired by the basis-expansion strategy in the traditional iterative approach for solving ISPs, a combined loss function with multiple labels is defined in a cascaded end-to-end CNN (CEE-CNN) architecture to decrease the nonlinearity of objective function, where no additional computational cost is introduced in generating extra labels. Third, to accelerate the convergence speed and decrease the difficulties of the learning process, the proposed CEE-CNN is designed to focus on learning the minor part of the induced current by introducing several skip connections and to bypass the major part of induced current to the output layers. The proposed method is compared with the state-of-the-art of deep learning scheme and a well-known iterative ISP solver, where numerical and experimental tests are conducted to verify the proposed ICLM.