Nonlinear artificial line models for power BAW resonators

The linear artificial transmission line model developed in 1986 by Morris and Hutchens is extended for nonlinear piezoelectric materials. Two new physical circuit models are proposed, one of them taking into account a mechanical nonlinearity while the other considers an electrical nonlinearity. Both nonlinearities are described by third degree polynomials. The measurements of the amplitude-frequency effect and of the frequency characteristic of the second harmonic reflected power have been compared with simulation results. The good agreement for AlN resonators with mechanical nonlinearity suggests that it can be the origin of their nonlinear behavior.