MEMS Pressure Sensor Electrode Amplifies Capacitance

The movable electrode system is segmented into two functional parts: the thin-film dome structure (which provides mechanical response to pressure) and the separate movable electrode plate (which provides the capacitive sensing surface). This segmentation allows each component to be optimized independently - the dome for mechanical performance and the electrode plate for electrical sensing - thereby resolving the contradiction between ease of manufacture and measurement precision

The patent introduces an intermediary movable electrode plate that couples the mechanical deformation of the thin-film dome to the capacitive measurement system. This intermediary element amplifies the capacitance change by providing a larger effective sensing area that moves in response to dome deformation, thus improving sensitivity while maintaining the simplicity of the underlying dome structure

By separating the structural function (performed by the stiff thin-film dome) from the sensing function (performed by the movable electrode plate), the system can maintain high structural integrity while achieving large capacitive response. The electrode plate is designed to move with the dome deformation, translating small dome movements into measurable capacitance changes without requiring the dome itself to be highly flexible

The patent changes the key parameter for sensitivity from dome displacement amplitude to capacitance change amplitude. By using a separate movable electrode plate with optimized geometry and positioning, the system achieves large capacitance changes even when dome displacement is limited by high stiffness requirements, thus decoupling strength from sensitivity