Wideband Photonic Radar Target Simulator Based on All-Optical IQ Upconverter

Radar target simulator (RTS) is extensively used in the development, debugging, and operation of automotive millimeter-wave radar systems. However, the performance of the traditional RTS based on digital radio frequency memory (DRFM) is limited by the complexity and spurious of radio frequency (RF) front end, the sampling rate of the analog-to-digital converter (ADC), and inherent delays in digital signal processing, which is hard to meet the urgent needs of wide bandwidth, low spurious distortion, high precision, and low delay. To solve this problem, a simple, multiband universal, high precision, and low-spur photonic RTS photonic RTS based on all-optical IQ upconverter is proposed. The experiment shows that the moving direction can be switched by flexible control of up- and down-frequency shifts, and accurate simulation of the target with different speeds can be achieved by a large-range-tunable Doppler frequency shift. In addition, the distance of the target can be flexibly tuned by optical delay, and the radar scattering cross section (RCS) can be simulated by wide-range power attenuation. Due to all-optical operation, the simulator has the advantages of adjustable working frequency (L–K band), large modulation bandwidth (dc to gigahertz level), and high spurious suppression (>30 dB). Moreover, the amplitude and phase of the generated simulated signal can also be adjusted, which is of great value in electronic warfare jamming and forwarding systems.