O.L. Balysheva, A.R. Zhezherin, Y.G. Smirnov

Passive SAW- sensor of inhomogeneous deformation was investigated. Relative SAW velocity shifts (dVo и dV), which appear at two points of the wafer because of its distortion, were taken as parameters of deformation. The SAW sensor layout with IDT and differential reflective system was proposed. The differential reflective system consists of two groove groups which placed symmetrically to the IDT. Parameters of deformation are determined by means of information signal analysis. Information signal is the part of sensor reaction on electrical test-impulse. Information signal is the sum of two acoustical pulses, reflected from different points of strained substrate and propagated with different velocities. The result of the sum depends strongly on whether the elementary acoustical pulses added with identical or opposite phases, according to substrate deformation. Through the use of differential reflective system the information signal is very sensitive to deformation parameter changes. The article gives sensitive element simulation results, which were obtained by means of equivalent electrical circuit model. The main sensitive element characteristics were calculated in connection with SAW device layout. The sensitive element reactions on some test signals have been defined. It is shown that the using chirp test signal and corresponding differential reflective system gives the opportunity of measure two deformation parameters (dVo и dV) simultaneously and independently from each other. The main metrological characteristics (measuring range, sensitivity, accuracy) were obtained in accordance with test signal parameters.