FMCW Radar Vibration Monitoring via Phase Demodulation

The patent replaces contact-based mechanical vibration sensors (accelerometers) with a non-contact FMCW radar system that uses electromagnetic waves to detect vibrations. The radar transmits chirp signals that reflect off the target object, and the phase information of the reflected signals contains vibration data. This substitution eliminates the need for physical contact while maintaining measurement capability through electromagnetic field interaction instead of mechanical coupling.

The patent introduces electromagnetic waves (FMCW radar signals) as an intermediary between the measurement system and the target object. Instead of direct mechanical contact, the radar waves serve as a mediator that carries information about the target's vibrations without physically attaching to or interfering with the target system, enabling non-invasive measurement.

The patent employs phase demodulation techniques that extract vibration information from the phase component of the reflected radar signal. By changing the measurement parameter from amplitude or frequency to phase information, the system achieves high precision non-contact vibration measurement. The phase of the beat signal contains detailed information about target displacement, velocity, and acceleration without requiring physical contact.

The patent uses periodic FMCW chirp signal transmission where the frequency modulated continuous wave signals are transmitted in repeated cycles. By accumulating and processing multiple periodic signal cycles, the system enhances the signal-to-noise ratio and improves measurement precision through coherent integration, allowing accurate vibration parameter extraction from weak reflected signals.