Features of Electromechanical Interactions in MEMS with a Solid-State Energy Source

The work is devoted to assessing the influence of the electrophysical parameters of the electret on the electromechanical characteristics of the variable capacitor with a built-in charge. A model of the variable capacitor with a built-in charge is considered and mathematical expressions are obtained to estimate the maximum possible parameters of MEMS: the critical displacement of the movable electrode, the magnitude of the external voltage and the electret surface charge density. It is shown that the critical displacement of the movable electrode with constant parameters of the dielectric layers and the increasing charge of the electret doesn't change, while the maximum allowable value of the external voltage decreases monotonically. It has been found that as the thickness of the dielectric layers, or their relative permittivities increase the maximum allowable displacement of the movable electrode, the built-in charge, and the applied external voltage also increase. As a result, the internal field of the electret as well as the energy stored by the variable capacitor which is necessary for performing useful work rise too. It has been observed that during the converter assembly process external factors can lead to a significant decrease of the electret effective voltage.