To address the demand for miniaturized, and low-power Synthetic Aperture Radar (SAR) systems in unmanned platforms, this study developed a high-speed imaging micro-system leveraging heterogeneous System-in-Package (SiP) technology. The system integrates an FPGA, a DSP, multiple DDR3 memory chips, and a LDO. Comprehensive electrical, thermal, and mechanical simulations validated the system’s signal integrity, thermal management, and structural robustness. Electrical simulations confirmed that key signals of DDR3-1600MT/s and 5 GT/s SerDes meet design requirements in terms of insertion loss, return loss, and crosstalk. Thermal simulations verified that the junction temperature of chips remains controllable with the application of a cold plate. Mechanical analysis demonstrated that the stress under thermal cycling and vibration shock conditions remains below the material limits. Imaging experiments showed close agreement between point-target responses, real-world data, and MATLAB simulations, with key metrics such as Peak Side Lobe Ratio (PSLR) meeting performance targets. These results demonstrate the micro-system’s viability for enabling lightweight, high-performance SAR processing in unmanned platforms.