Scalable distributed microwave photonic MIMO radar based on a bidirectional ring network

A scalable distributed microwave photonic multiple-input-multiple-output (MIMO) radar is proposed based on a bidirectional ring network. The network is constructed with a fiber ring on which a local node and several remote nodes are distributed. In the local node, radar signals are generated over different optical wavelengths based on external modulation. Employing wavelength-division multiplexing, the radar signals are sent to remote nodes through the fiber ring. In different remote nodes, radar signals modulated on corresponding wavelength are utilized for transmitting or photonic de-chirp processing. Benefiting from the bidirectional ring network, the proposed radar is suitable for large-scale distribution. Together with the pluggable remote nodes, the scalability of the radar is enhanced. A proof-of-concept experiment is demonstrated to verify the feasibility of the system. Measurements of two-dimensional position and velocity of targets are realized. The position error and velocity error are better than 8 cm and 0.20 m/s respectively.