Microwave photonic signal generation for radar applications

Signal source is a key component in both the transmitter and the receiver of a radar system, and its property determines the performance of the radar system. Currently, the signal generation based on pure electronic technologies is limited in aspects of carrier frequency, signal bandwidth, and noise properties, which cannot meet the requirement of high frequency, large bandwidth and low noise signals in further high performance radar applications. Microwave photonics, as a newly arisen and promising technology, can generate microwave signals with the advantages of high frequency, large bandwidth and superior noise performance. This paper presents the recent progress of radar signal generation by microwave photonic technologies. Specifically, the generation of high-quality local oscillator signal based on optoelectronic oscillators, and the generation of phase-coded or linear frequency modulated (LFM) microwave signals are discussed. Through the analysis of the above techniques, it is found that microwave photonic signal generation is a promising solution to break through the bottleneck in current radar signal generations.