基于光子学的微波移频方法研究

Microwave Frequency Shift (MFS) technology is widely used in electronic countermeasures, satellite communications and frequency diverse array radar. The MFS method based on photonics has the advantages of large bandwidth and pure spectrum. In order to explore the performance, three MFS methods based on Acousto-Optic Frequency Shifter (AOFS), Sawtooth Phase Modulation (SPM) and I/Q modulation are compared in this paper. The principles of the three methods are illustrated and the corresponding verification systems are built for experiments and analysis. The results show that the three methods can achieve accurate MFS whose spurious suppression ratios are greater than 30 dB. However, the three methods simultaneously have different limitations: the operating frequency, bandwidth, and frequency shift direction of AOFS are relatively fixed which means the tunability is low; methods based on SPM and I/Q modulation have strict requirements on the input driving signal which leads to poor stability.