The Impact of Signal Quality in Dielectrophoresis Experiments

The impact of signal quality on dielectrophoresis experiments is investigated. Three frequencies providing a positive, a negative, and a vanishing real part of the Clausius Mossotti factor are compared using different signal resolutions. Sinusoidal signals are applied with 3 to 10 bit resolution, a total harmonic distortion of -60 to -20 dB, and a spurious free dynamic range from 27 to 65 dB. An experiment is performed with carboxyl functionalized 4.5 µm polystyrene microspheres in deionized water using an electrode pair in a microfluidic channel. Signal qualities with resolutions smaller than 7 bit induce unwanted DEP forces or lower the net force.