US Patent 7461558 Capacitive pressure sensor with sealed reference chamber

A capacitive pressure sensor includes a substrate assembly. The substrate assembly includes a conductive layer and defines a plurality of channels terminating in closed ends. A conductive membrane is mounted to the substrate assembly so that a sealed reference chamber including the channels is defined by the conductive membrane and the substrate assembly. A cap is mounted relative to the substrate assembly and defines one or more apertures so that an antechamber is defined by the cap and the conductive membrane. Differential pressure between the reference chamber and antechamber can cause deflection of the conductive membrane which, in turn, varies the capacitance between the conductive membrane and conductive layer.