At least one pair of capacitively coupled electrodes contained in a structure is used to sense the deflection of a diaphragm in a pressure or force sensor for measuring the pressure or force exerted on the diaphragm. Preferably the structure has properties (such as one or more of the following: dimensions, hardness, area and flexibility) that are substantially the same as those of a real substrate, such as a semiconductor wafer or flat panel display panel.