Wavelength division sensing RF vibrometer

A wavelength division sensing RF vibrometer which is implemented as a tunable carrier frequency Doppler radar sensor was used for the first time to accurately measure mechanical vibrations of complex patterns. The amplitude ratio of a pair of baseband harmonics under different carrier wavelengths was used to obtain the vibration patterns. A software-controlled PLL was built to generate carrier frequencies from 5.5 to 6.5 GHz. The accuracy of the recovered vibration pattern using the noncontact RF vibrometer rivals other contact measurement instruments, such as LVDT and accelerometer.