One embodiment in accordance with the invention includes a capacitive sensing apparatus that includes a capacitive sensor configured to sense an object proximate to a physical capacitive sensing reference surface. The capacitive sensing apparatus also includes a plurality of dielectric materials disposed between the capacitive sensor and the physical capacitive sensing reference surface. Note that at least one of the plurality of dielectric materials has a non-uniform thickness. The plurality of dielectric materials can be configured such that capacitive coupling between the capacitive sensor and the object proximate to the physical capacitive sensing reference surface is substantially constant across the physical capacitive sensing reference surface.