Patent ID: 7838822

Claim:
A high-field asymmetric-waveform apparatus for a differential ion mobility spectrometer comprising: a first electrode; a second electrode with substantially constant spacing to the first electrode; a first high-voltage waveform generator producing a sinusoidal waveform at a first frequency and at a first amplitude, the first waveform generator electrically connected to the first electrode, the first frequency value being adjustable and first amplitude value being adjustable; a second high-voltage waveform generator, electrically producing a sinusoidal waveform at a second frequency and at a second amplitude, the second waveform generator electrically connected to the second electrode, the second frequency value being adjustable and second amplitude value being adjustable, the second frequency value being a harmonic of the first frequency value; a phase adjusting circuit adapted to adjust the phase of at least one of the waveform generators; wherein the electric field created between the first electrode and second electrode, resulting from the application of the first high-voltage waveform and second high-voltage waveform, is asymmetric and has a time-averaged value substantially equal to zero.