Photonics-Based Multidomain Features Extraction for Radio Frequency Signals

A photonics-based multidomain features extraction approach for radio frequency (RF) signals is proposed and demonstrated. Through the time-mapped Fourier transform (TM-FT) and optical interference on the RF signals captured by multiple antennas, the spectrum and the 2-D angle of arrival (AOA) of the RF signals are mapped to the time domain simultaneously. Thus, the simultaneous multidomain features extraction of the RF signals will be guaranteed. In addition, due to the use of the chirped optical pulse with MHz repetition rate as the time window for the features extraction, the proposed scheme can analyze wideband and transient RF signals. In the experiment, the multidomain features of 4-GHz wideband RF signals and 5-ns RF transient signals are extracted, and the signal types are classified successfully. The frequency measurement range of 6–16 GHz with an error of
$\pm$
25 MHz and the 2-D AOA measurement range of
$\pm$
40
$^{\circ}$
with an error of
$\pm$
2.5
$^{\circ}$
are verified. The proposed approach provides an innovative option for real-time multidomain features extraction and classification of RF signals in complex electromagnetic environments.