Non-Contact Measurement of Periodic Movements by a 22-40GHz Radar Sensor Using Nonlinear Phase Modulation

A non-contact detection technique of measuring both the frequency and the amplitude of periodic movement using the property of nonlinear phase modulation is proposed and demonstrated by a 22-40 GHz radar sensor. It is shown that this method has the following advantages: (1) no calibration of signal amplitude required for accurate measurement of movement amplitude; (2) ability of self-verification; (3) very simple architecture. The method can be used to detect movements with amplitudes larger than 0.335 of the carrier wavelength for a fixed carrier frequency system and 0.214 of the minimum carrier wavelength for a frequency tunable system. By analyzing and simulating the wide angle incidence effect, it is shown that a proper choice of radio frequency, measurement distance, and antenna pattern can ensure accurate measurement of movement amplitudes.