Design of Omnidirectional Reflectionless Absorbing Surface for Dual-Frequency Microwave Imaging

Inverse scattering-based microwave imaging has been an important subject of scientific research and practical engineering for centuries. In practice, anechoic chambers were always chosen as the optimal operating environment for microwave imaging. With large floor space and ultrahigh cost of an anechoic chamber, microwave imaging experiments in practical engineering applications remain a technical challenge. In this study, dual-frequency and dual-angle reflectionless absorbing units were designed and implemented, based on which a portable miniaturized imaging chamber was further established. For demonstration, practical imaging experiments were performed to reconstruct the profile of the object under imaging (OUI) which verified the effectiveness of the implemented dual-frequency imaging chamber. Taking advantage of the design method, imaging chambers can be customized on demand of the desired size of the OUI. With a dual-frequency imaging algorithm, we foresee the improvement of the image quality of the OUI which is of great importance for practical application.