Surface acoustic wave (SAW) pressure sensor structure

Claim 1

A surface acoustic wave (SAW) pressure sensor structure, comprising: a SAW pressure sensor including a SAW delay line disposed in an active signal region on a first one of two parallel major surfaces of a substrate, said substrate having a deformable diaphragm formed therein coextensive with said active signal region, said diaphragm having a membrane thickness determined by the relative displacement of said first surface from a parallel interior surface defined by the end wall of a cylindrical cavity formed in the second major surface of said substrate, a vacuum sealing enclosure including a base portion and a cover portion joined in a vacuum sealing relationship and adapted to receive said SAW sensor in a vacuum chamber formed therebetween, said base portion including an orifice therethrough adapted for alignment with said cavity in said substrate; and a cylindrical metal sleeve having a central aperture formed along the length thereof and joined in a vacuum sealing relationship at opposite ends thereof to said cavity and to said orifice for providing a fluid conduit for external pressure signals through said vacuum environment from said orifice to said cavity, said sleeve supporting said SAW pressure sensor in displacement from said base portion at a distance which is from ten to twenty times greater than the wall thickness of said sleeve.