Fast <scp>3D</scp> microwave imaging inside cavity with minimum number of antennas and modified inverse algorithm

Abstract This article proposes an optimized method for 3D microwave imaging of various unknown objects inside a perfect electric conductor cavity. The total field scattered field technique uses the finite difference time domain method to obtain scattered fields inside a cavity in the forward scattering problem. However, the conjugate gradient method is optimized and used alongside a combined regularization term in the inverse scattering problem, which is essential for the reconstruction process. A dipole antenna is located as an incident wave from the transmitting antenna. Besides, one antenna acts as the receiver. Identifying the unknown objects with different shapes, sizes, materials, and locations using the minimum number of transmitting and receiving antennas, and the newly developed algorithm with less computation time, are the main advantages of this article. Also, the implemented method can be used in the 3D microwave imaging of multi‐scattering problems.