An Efficient Method for Modeling Planar Interdigitated Electrodes for Capacitive Sensing
Sprache des Vortragstitels:
IEEE Sensors 2011 Conference
Sprache des Tagungstitel:
Interdigitated electrodes represent a commonly used planar structure when it comes to implementing capacitive sensors. The electric field decays strongly in the surface normal direction of the electrode arrangement. This can be used to estimate the thickness of dielectric films residing on the electrodes. On the other hand, it can also be used to determine the permittivity of the adjacent half-space, where often a passivation layer is deposited to protect the electrodes from the environment. By using a multiple electrode arrangement utilizing a flexible wiring scheme involving active electrodes and electrically floating electrodes, both the thickness of the layer and the permittivities can be assessed. The exact expressions for the associated capacitances are relatively complex and can be provided in closed form only for the case without a covering layer. In this contribution, we present a highly efficient semi-numerical modeling approach for the calculation of the required capacitances.