Photonic-Assisted Broadband Linear Frequency-Modulated Waveform Generation Based on Spectrum Stitching

Owing to the instantaneous bandwidth of linear frequency-modulated waveform (LFMW) generated by electronic methods in radar systems is only a few GHz, it is difficult to meet the future performance requirements for radar signals. To solve this problem, this paper proposes a broadband LFMW generation scheme based on spectrum stitching by using microwave photonic technology to enhance the time-bandwidth product (TBWP) of the LFMW. Firstly, the scheme has a simple structure, requiring only a recirculating frequency shift module, a modulation module, and a baseband waveform generator. Through digital simulation, an LFMW as broad as 6 GHz is generated from a baseband LFMW with 1 GHz bandwidth, and the TBWP is 36 times that of the baseband signal. In addition, the proposed approach has the advantage of high tunability. Finally, the generated signal shows good sidelobe suppression and pulse compression performance by analyzing its autocorrelation function.