Robust Weak Signal Detection in High-Interference Environments Using Orbital Angular Momentum Waves

Detecting weak signals in high-interference environments is a critical challenge across various fields, including radar and communication systems. Traditional methods often fail when the signal-to-noise ratio (SNR) is extremely low. Here, we propose two novel methods for weak signal detection using orbital angular momentum (OAM) waves. These methods leverage the unique periodic characteristics of synthetic waves composed of OAM and plane waves. By recombining a new electric field using the mean amplitude and phase of the synthetic wave, or the mean of the maximum and minimum amplitudes and the mean phase, we demonstrate the extraction of OAM waves from synthetic waves with an amplitude difference of 22 dB. This corresponds to a power ratio of 158.76 times between the interference and the OAM wave. Our methods enable the detection of weak linear frequency modulation (LFM) signals carried by OAM waves in strong noise backgrounds, even at an SNR as low as -30.98 dB. This represents a significant advancement, providing robust signal detection capabilities that could transform radar detection, radar anti-interference, and communication transmission. Our results are supported by both theoretical analysis and experimental validation.