Delta operator technique to improve the Thomson–Haskell‐method stability for propagation in multilayered anisotropic absorbing plates

A modified version of the transfer‐matrix method that models propagation of heterogeneous plane waves through immersed multilayered plates made of anisotropic absorbing layers is presented. Since this method suffers from numerical instabilities, the so‐called delta matrix operator is applied. As for propagation through isotropic media, the case of propagation in the principal plane of anisotropic media requires us to define sixth‐order delta matrices. This method eliminates numerical difficulties. The same technique is used for propagation out of the principal plane. Fifteenth‐order delta matrices are necessary to get improved results. However, numerical problems persist with computational data corresponding to the usual experimental situations. Then, a modified version of the delta matrix operator is proposed. From the reflection and transmission coefficients expressions, both 15th‐ and 20th‐order delta matrices are necessary to get reliable numerical results, whatever the computational data may be.