IMPROVED CAPACITIVE BASED PRESSURE SENSOR DESIGN

摘要

A pressure transducer assembly includes a first body, a diaphragm, and an electrode. The diaphragm is mounted between the first and second bodies. The first body and the diaphragm form a first chamber. The second body and the diaphragm form a second chamber. The electrode is disposed in the first chamber. A portion of the diaphragm flexes in a first direction in response to pressure in the first chamber being greater than pressure in the second chamber. A portion of the diaphragm flexes in a second direction, opposite the first direction, in response to pressure in the second chamber being greater than pressure in the first chamber. A capacitance between the electrode and the diaphragm is representative of a difference between the pressures in the first and second chambers. In some embodiments, the electrode is suspended from a hub and spoke mounting. In some embodiments the electrode is entirely metallic. In other embodiments, the electrode includes a ceramic disk with a conductive film formed on the disk and the disk is coupled to the housing with a ceramic rod. In some embodiments, the transducer also has a low thermal coefficient of expansion member connected to the housing for reducing warping in response to temperature changes. In additional embodiments, the disk includes a groove that reduces the effects of temperature variations on a ceramic electrode.