Temperature stable piezoelectric substrates for SAW gas sensors

A systematic search of several surface acoustic wave (SAW) substrates and crystallographic orientations has been conducted in an effort to identify temperature compensated cuts. As a result of this search, a sequence of crystallographic orientations along the rotated Y-cut (RYC) in quartz has been identified as appropriate for operation over a broad range of temperatures. Theoretical calculations, in fact, show that different orientations along RYC quartz provide compensation at temperatures ranging from -35 degrees C to over 500 degrees C, thereby allowing one to select an appropriate temperature stable orientation for a particular application. Experimental measurements performed on selected RYCs in quartz have confirmed these predictions of temperature stability.