This paper deals with a new theoretical approach using micro- and nano-electromechanical systems to build alternating current (ac) voltage standards. The principle is based on the quadratic variation of the capacitance due to the displacement of at least one of the micro-machined electrodes as a result of an applied electrostatic force. In these systems the voltage reference presents a plateau according to the ac driving current, which makes it possible to define an ideal current-independent ac voltage standard as in dc voltage metrology using Zener diodes. This new approach allows us to define a voltage reference given by the value of the voltage plateau instead of just a single operating point in the well-known pull-in effect approach, in which the variation of the capacitance with the displacement is hyperbolic. Moreover, the working frequency range in this new approach is wider and is no longer limited by the mechanical resonance frequency of the system. Two microsystem architectures are proposed to realize such devices: the first one is based on electrodes in the shape of a triangle and the second one uses split finger electrodes with unequal lengths.
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