Capacitive pressure sensor

A pressure sensor, comprising:

• a probe body;
• a pressure deflectable diaphragm end formed of a conductive material and coupled to the probe body, the conductive material having a first coefficient of thermal expansion, the pressure deflectable diaphragm end having a first surface defining at least a first portion of a capacitor;
• an alumina disk having a second coefficient of thermal expansion that is less than the first coefficient of thermal expansion, the disk including a metallization layer, with the metallization layer being spaced from the first surface such that the metallization layer at least partially defines a second portion of the capacitor;
• a spring disposed between the probe body and the alumina disc, the spring biasing the alumina disk toward the pressure deflectable diaphragm end;
• and
• an annular shim component disposed at a peripheral region of the alumina disk and isolating the alumina disk from the pressure deflectable diaphragm end, the annular shim being formed of a third material having a third coefficient of thermal expansion;
• wherein the third coefficient of thermal expansion is less than the first coefficient of thermal expansion.

A pressure sensor comprising:

• a probe assembly including:
• a relatively rigid body;
• a distal end having a capacitive pressure sensor, the capacitive pressure sensor capable of producing a sensed capacitance as a result of pressure acting on the capacitive pressure sensor;
• and
• a proximal end opposite the distal end;
• an intermediate circuit enclosure disposed at the proximal end;
• a capacitive detection bridge circuit housed within the intermediate circuit enclosure, the capacitive detection bridge circuit producing an electrical voltage signal proportional to a difference between a reference capacitance and the sensed capacitive signal;
• a remote circuit enclosure;
• a relatively flexible interconnect coupling the remote circuit enclosure to the intermediate circuit enclosure;
• and
• a main circuit disposed in the remote circuit enclosure, the remote circuit enclosure connected to the intermediate circuit enclosure by the relatively flexible interconnect, the capacitive detection bridge circuit transmitting the electrical voltage signal to the main electrical circuit through the interconnect.