First Multi-chirp-rate & Multi-band Converged ISAR Powered by Photonic Integrated Circuit

Photonics-enabled multi-chirp-rate & multi-band converged inverse synthetic aperture radar (ISAR) is proposed. The multi-band convergence brings a wide equivalent bandwidth, and more importantly the multi-chirp-rate convergence lends to a greatly simplified receiver hardware (Multiple in One). An integrated photonic prototype is fabricated via lithium-niobate-on-insulator (LNOI) platform, wherein one modulator with ultra-low half-wave voltage for generating multi-chirp-rate & multi-band signal and the other modulator for de-chirping this signal. In the experiment, a linearly frequency modulated (LFM) seed signal with 0.36-GHz bandwidth is applied to generate radar signal with 3 bands (0.36, 0.72 and 1.08 GHz) and 3 chirp rates (1.8×10
⁵
, 3.6×10
⁵
and 5.4 ×10
⁵
GHz/s). An ISAR turntable imaging with a 1.88-cm range resolution is achieved using a single receiver hardware, rather than multiple parallel ones for multiple bands. This multi-chirp-rate & multi-band convergence enables a large equivalent bandwidth and a compact hardware.