Computational imaging using a mode-mixing cavity at microwave frequencies

International audienceWe present a 3D computational imaging system based on a mode-mixing cavity at microwavefrequencies. The core component of this system is an electrically large rectangular cavity with onecorner re-shaped to catalyze mode mixing, often called a Sinai Billiard. The front side of the cavityis perforated with a grid of periodic apertures that sample the cavity modes and project them intothe imaging scene. The radiated fields are scattered by the scene and are measured by low gainprobe antennas. The complex radiation patterns generated by the cavity thus encode the scene informationonto a set of frequency modes. Assuming the first Born approximation for scatteringdynamics, the received signal is processed using computational methods to reconstruct a 3D imageof the scene with resolution determined by the diffraction limit. The proposed mode-mixing cavityis simple to fabricate, exhibits low losses, and can generate highly diverse measurement modes.The imaging system demonstrated in this letter can find application in security screening and medicaldiagnostic imaging