Discussion about generation mechanisms of third-order nonlinear signals in surface acoustic wave resonators based on simulation

Abstract

In this paper, we discuss the generation mechanisms of third-order nonlinearity in surface acoustic wave (SAW) devices on the basis of simulation results, which are obtained by a proposed method for this discussion. First, eight nonlinear terms are introduced to the piezoelectric constitutive equations, and nonlinear stress and electric flux fields are estimated using linear strain and electric fields calculated by a linear analysis, i.e., the coupling of mode simulation. Then, their contributions are embedded as voltage and current sources, respectively, in an equivalent circuit model, and nonlinear signals appearing at external ports are estimated. It is shown that eight coefficients of the nonlinear terms can be determined from a series of experiments carried out at various driving and resulting frequencies. This is because the effect of each nonlinear term on the nonlinear signal outputs changes markedly with the conditions. When the coefficients are determined properly, the simulations agree well with some measurement results under various conditions.

Investigation on Third-Order Intermodulation Distortions Due to Material Nonlinearities in TC-SAW Devices

“…Good crystallinity leads to longer lifetime. Therefore, to retain the metal electrode crystallinity, Nakagawa et al [9] introduced a titanium (Ti) layer underneath the Al layer in order to reduce the acoustic strain generated by the SAW in the Al layer [17]. It should be noted that the material and wave polarization used in [9] and [17] are different from our investigation.…”

Research in Nonlinearity of Surface Acoustic Wave Devices

“…Apart from the possible causes, generation points of nonlinear signals [7][8][9][10][11][12][13][14], whether in the substrate or in electrodes, are also important. Previous works show that the secondorder nonlinearity in SAW devices on 42 • XY-LiTaO 3 (42-LT) substrates is mainly generated by the crystalline asymmetry on the surface of a piezoelectric substrate, and the nonlinear dielectric constant and the electrostrictive constant contribute to the generation of secondorder nonlinear signals.…”

“…Furthermore, the width of the electrode also has a great influence on the nonlinear effect. Usually the wider the electrode width, the more obvious the nonlinear effect [9][10][11][12][13][14].…”

“…Even so, research teams including Qorvo, Murata, and Chiba University [3,6,[8][9][10][11][12][13]22,31] have built and implemented the measurement systems on harmonics and intermodulation of nonlinearity for SAW devices. Moreover, our team also developed a harmonics and intermodulation measurement platform for SAW resonators, filters, and duplexers both on-chip and on PCB board.…”

Properties of engine oil measured using a surface acoustic wave sensor

“…An SAW device is mainly used as a high-frequency electronic device such as a filter. [5][6][7][8][9] SAW devices have been applied to sensors and actuators. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] As the SH-SAW can propagate at a liquid=solid interface, a liquid sensor is realized with an SH-SAW sensor.…”