Ultra-high resolution displacement-sensing doppler radar

A method for detecting object displacements using a Doppler radar, the method comprising:

• generating a transmitted signal of a first frequency;
• radiating the transmitted signal toward a target object to cause the transmitted signal to be reflected off the target object;
• receiving a returned signal reflected off the target object carrying displacement-induced phase delays corresponding to a type of detected displacement of the target object;
• mixing the received signal with a local oscillator (LO) signal to generate a down-converted intermediate frequency (IF) signal, wherein the down-converted IF signal carries the displacement-induced phase delays;
• processing the down-converted IF signal so that the displacement-induced phase delays is converted into a modulated pulse signal;
• and
• converting the modulated pulse signal into an output signal having a voltage value indicative of the detected displacement.

A displacement-sensing apparatus, comprising:

• a transmitting antenna;
• a receiver antenna;
• and
• a continuous wave (CW) Doppler radar coupled to the transmitting antenna and the receiver antenna, wherein the CW Doppler radar further comprises:
• a first frequency synthesizer configured to generate a transmitted signal of a first frequency, which is radiated by the transmitting antenna toward a target object;
• a low noise amplifier (LNA) configured to amplify a received signal outputted by the receiver antenna, wherein the received signal is generated based on a returned signal reflected off the target object, and wherein the returned signal carrying displacement-induced phase delays corresponding to detected displacements of the target object;
• a mixer configured to mix the received signal and a local oscillator (LO) signal to generate a down-converted sine-wave intermediate frequency (IF) signal, wherein the down-converted sine-wave IF signal carries the displacement-induced phase delays;
• a rectifier configured to convert the sine-wave IF signal into a square-wave IF signal, wherein the displacement-induced phase delays are embedded in the rising/falling edges of the square-wave IF signal;
• a phase demodulation module configured to convert the displacement-induced phase delays into a modulated pulse signal;
• and
• a low-pass filter (LPF) configured to convert the modulated pulse signal into an output signal having a voltage value indicative of the detected displacements.