Abstract: In response to the miniaturization requirements of airborne radar for motion platforms such as rotor unmanned aerial vehicle, frequency modulated continuous wave (FMCW) synthetic aperture radar (SAR) has more advantages in miniaturization than pulsed SAR. A FMCW SAR system is designed and implemented based on the design concept of miniaturization and low power consumption. First, the hardware components of each subsystem are analyzed and elaborated. Then the signal models are designed in detail and the traditional algorithms are improved. Finally, the system performance indicators are verified through the field slide imaging experiment, indicating that the system is effective and feasible, and it can provide an effective reference for the designs of similar systems.