Single-Shot Compressive Multiple-Inputs Multiple-Outputs Radar Imaging Using a Two-Port Passive Device

This paper presents a compressive technique that simplifies the architecture of multiple-input multiple-output (MIMO) radar imaging systems. By means of a passive device connected to an MIMO array of antennae, a novel approach is introduced to extract the interaction between antennae from a compressed signal measured between two ports. This technique relies on a multiplexing principle that exploits the frequency diversity and it is thus particularly suitable for ultrawideband imaging systems. This paper presents the theoretical principle underlying this compressive technique, defining the key parameters affecting the information retrieval from a measured frequency signal and the prior characterization of the compressive device's transfer functions. Simulations are performed to demonstrate the potential of the technique for MIMO ultrawideband imaging systems and its compatibility with fast range migration algorithms based on fast Fourier transforms. Finally, an experimental validation is performed with a two-dimensional radiating aperture connected to a compressive device, allowing for the three-dimensional near-field imaging of different targets.