Shi Taixia, Liang Dingding, Wang Lu, Li Lin, Guo Shaogang, Gao Jiawei, Li Xiaowei, Lin Chulun, Shi Lei, Ding Baogang, Liu Shiyang, Yang Fangyi, Jiang Chi, Chen Yang
Author Affiliations
East China Normal UniversityBeijing Institute of Control EngineeringShanghai Lujie Communication Technology Company Limitedshow less
Abstract
A microwave photonic prototype for concurrent radar detection and spectrum sensing is proposed. A direct digital synthesizer and an analog electronic circuit are integrated to generate an intermediate frequency (IF) linearly frequency-modulated (LFM) signal ranging from 2.5 to 9.5 GHz, with an instantaneous bandwidth of 1 GHz. The IF LFM signal is converted to the optical domain via an intensity modulator and filtered by a fiber Bragg grating (FBG) to generate two 2nd-order sidebands. The two sidebands beat each other to generate a frequency-and-bandwidth-quadrupled LFM signal. By changing the center frequency of the IF LFM signal, the radar function can be operated within 8 to 40 GHz. One 2nd-order sideband works in conjunction with the stimulated Brillouin scattering gain spectrum for microwave frequency measurement, providing an instantaneous measurement bandwidth of 2 GHz and a frequency measurement range from 0 to 40 GHz. The prototype is demonstrated to be capable of achieving a range resolution of 3.75 cm, a range error of less than ±2 cm, a radial velocity error within ±1 cm/s, delivering clear imaging of multiple small targets, and maintaining a frequency measurement error of less than ±7 MHz and a frequency resolution of better than 20 MHz.