Analysis of the natural single phase unidirectional SAW transducer

The calculation of fundamental parameters needed for the analysis of a natural single-phase unidirectional transducer (NSPUDT) is reported. Analytical forms for the NSPUDT parameters on arbitrary crystal cuts are given in terms of material constants and electrode geometry. The acoustic-wave velocity, electromechanical-coupling parameter, power-flow angle, static capacitance, transduction coefficient, and reflection from a single strip due to both electrical and mechanical perturbations are found as a function of the propagation angle on ST quartz. The coupling-of-nodes (COM) theory is then used to analyze a practical NSPUDT device. From solutions of the coupled mode equations, the characteristics of radiation admittance and insertion loss are found. The COM-model is verified by comparison with measurements of a device built on an unconventional orientation on ST quartz.<<ETX>>

[1]  Supriyo Datta,et al.  Surface Acoustic Wave Devices , 1986 .

[2]  Analysis of SAW reflection , 1988, IEEE 1988 Ultrasonics Symposium Proceedings..

[3]  P. Wright.  Low-cost high-performance resonator and coupled-resonator design: NSPUDT and other innovative structures , 1989, Proceedings of the 43rd Annual Symposium on Frequency Control.

[4]  David Morgan,et al.  Surface-wave devices for signal processing , 1985 .

[5]  P. V. Wright,et al.  The Natural Single-Phase Unidirectional Transducer: A New Low-Loss SAW Transducer , 1985, IEEE 1985 Ultrasonics Symposium.

[6]  A. J. Slobodnik,et al.  Microwave Acoustics Handbook. Volume 3. Bulk Wave Velocities. , 1980 .

[7]  T. Thorvaldsson,et al.  Rigorous Derivation of the Mason Equivalent Circuit Parameters from Coupled Mode Theory , 1986, IEEE 1986 Ultrasonics Symposium.

[8]  J.J. Campbell,et al.  A method for estimating optimal crystal cuts and propagation directions for excitation of piezoelectric surface waves , 1968, IEEE Transactions on Sonics and Ultrasonics.

[9]  B. Auld,et al.  Acoustic fields and waves in solids , 1973 .

[10]  H. Haus,et al.  Analysis of Metal-Strip SAW Gratings and Transducers , 1985, IEEE Transactions on Sonics and Ultrasonics.

[11]  P. V. Wright,et al.  A new generalized modeling of SAW transducers and gratings , 1989, Proceedings of the 43rd Annual Symposium on Frequency Control.