Experimentally determining the transduction magnitude and phase and the reflection magnitude and phase of SAW SPUDT structures

An experimental method for determining all the key parameters of a SPUDT (single-phase unidirectional transducer) is presented. These include certain parameters which have not been measured before experimentally (such as the phases of reflection and transduction), as well as parameters which are difficult to measure (such as the propagation loss inside the SPUDT structure). Wave velocities and propagation losses both inside and outside the SPUDT test structure can be determined. In addition, the method determines the frequency dependence of all key model parameters. The method is based on nonlinear least-squares fitting of seven theoretical expressions containing the model parameters to corresponding measured data from a special five-transducer test device. Resulting model parameters have estimated accuracies which are typically 1% to 0.001%. A user-friendly software package using this method displays superposed plots of experimental and theoretical functions