Abstract: A piezoelectric sensor and assembly for measuring chemical, biochemical and physical measurands is disclosed. The piezoelectric sensor comprises a piezoelectric material, preferably a crystal, a common metal layer attached to the top surface of the piezoelectric crystal, and a pair of independent resonators placed in close proximity on the piezoelectric crystal such that an efficacious portion of acoustic energy couples between the resonators. The first independent resonator serves as an input port through which an input signal is converted into mechanical energy within the sensor and the second independent resonator serves an output port through which a filtered replica of the input signal is detected as an electrical signal. Both a time delay and an attenuation at a given frequency between the input signal and the filtered replica may be measured as a sensor output.

Abstract: A Quartz Crystal for surface acoustic wave device application defined by the Euler angles lambda (.lambda.) equal about 45.degree. and mu (.mu.) equal about 55.degree. with an acoustic wave propagation direction angle theta (.theta.) equal plus about 10.degree. to minus about 30.degree..

Abstract: A piezoelectric wafer of single crystal berlinite, having a surface defined by an X-axis boule cut at an angle in the range from about 94.degree.-104.degree., provides an improved substrate for a surface acoustic wave device. These cut angles are relatively easy to fabricate, provide excellent temperature compensation in a range from -55.degree. C. to 125.degree. C., and have high piezoelectric coupling coefficient.

Abstract: A piezoelectric wafer of single crystal berlinite, having a surface defined by an X-axis boule cut at about 85.degree., provides a improved substrate for a surface acoustic wave device. The 85.degree. cut angle is relatively easy to fabricate, provides excellent temperature compensation in a range form 20.degree. C. to 100.degree. C., and has high piezoelectric coupling coefficient.