Ultra-high Resolution Real-time Radar Imaging Based on Microwave Photonics

Microwave photonic technology is a promising solution to overcome the bandwidth limitations in radar and communication systems. Recently, photonics-based radar has attracted lots of attention because of its ultra-high resolution enabled by the large operation bandwidth. In this report, we review our recent investigations on a photonics-based radar and its application in target imaging. The radar generates broadband linear frequency modulation signal by photonic frequency multiplication, and implements de-chirping in the receiver by microwave photonic frequency mixing. Its large operation bandwidth and real-time signal processing capability make it possible for realize ultra-high resolution and real-time imaging. With an established Ka-band 12 GHz bandwidth photonics-based radar, a range resolution as high as 1.3 cm is achieved. High-resolution and real-time inverse synthetic aperture radar (ISAR) imaging is also demonstrated through a turntable imaging experiment and a field trial target imaging experiment. The results prove that photonics-based radar is an effective solution to overcome the limitations on operation bandwidth and processing speed of current radar imaging technologies. To further improve the radar imaging performance such as a higher cross-range resolution, we propose a possible solution by constructing a photonics-based multiple input multiple output (MIMO) radar, which combines the photonics-based radar with the MIMO technique. Through numerical simulations, we show the advantage of radar imaging with the photonics-based MIMO radar.