Wideband High-Accuracy Microwave Frequency Measurement and Recognition Enabled by Stimulated Brillouin Scattering

We have developed a high-accuracy, wideband microwave frequency measurement (MFM) system based on frequency-to-time mapping (FTTM) enabled by stimulated Brillouin scattering (SBS). This system, now at the prototype stage, utilizes a broadband linear frequency modulated (LFM) pulse signal as the local signal, which is modulated onto the pump lightwave, while the detected signals are modulated onto the probe lightwave. By analyzing the time values at which Brillouin gain or loss occurs in the pump signal, the frequency of the detected signal can be accurately determined. In experiments, the system successfully measured various signal types, including monotone, multitone, LFM, and Costas frequency modulated signals, as well as their combinations, across a frequency range of 1 GHz to 39 GHz. The system achieves a frequency measurement error below 20 MHz, with a root mean square error (RMSE) of 9.74 MHz, and supports an instantaneous bandwidth of up to 12 GHz across C, X, and Ku bands. Furthermore, leveraging Brillouin loss, the system achieves 100% recognition accuracy for nine distinct microwave signal categories, including both individual and composite signals ranging from 0.47 GHz to 19.47 GHz-a first in the field. Notably, this is accomplished at a system sampling rate of only 50 MSa/s, significantly lower than traditional electronic recognition techniques. This breakthrough represents a significant advancement in electronic reconnaissance and warfare, offering a highly effective solution for frequency measurement and signal recognition with reduced computational and hardware requirements.