A new architecture for a widely distributed dual- band coherent multiple-input multiple-output (MIMO) radar system is illustrated, and its implementation and testing are reported. The system consists in a central unit based on a single mode-locked laser, supporting multiple remote radar nodes linked by standard optical fiber pairs. Every remote node operates both in the S- and X-band, and it can be displaced over distances of several kilometers, allowing to monitor a scene under different angles of view. All the remote nodes share the same oscillator and digital signal processing unit, both located in the central node. This architecture allows to perform centralized data fusion on the signals acquired by the remote nodes, and, by virtue of ...