A Coherent Dual-band FMCW Photonic Radar Based on a Synchronized FMCW Optoelectronic Oscillator

This paper proposes and experimentally demonstrates a novel coherent radar architecture based on a synchronized frequency-modulated continuous-wave optoelectronic oscillator. The approach overcomes intrinsic limitations of conventional RF systems, such as harmonic generation and synchronization difficulties, and allows the generation of wideband FMCW signals. The proposed architecture employs the direct modulation of a tunable laser source to create a swept optical frequency. The configuration, termed anFMCW OEO, inherently produces a widebandFMCWRF signal.We further introduce a synchronization mechanism through the integration of a voltage-controlled phase shifter and a phase-locked loop. This arrangement allows the system to be phase-locked to a stable RF reference. The generation of a coherent dual-band FMCW signal is demonstrated. The generated signals in both X- and Ku-bands achieved bandwidths wider than 1.5 GHz. A radar experiment that detected and tracked a moving metallic plate target validates the feasibility of the proposed system.