Modeling of electromagnetic and acoustical properties of RF SAW filters from on-chip layout including all electrodes and comparison with experimental data

We describe a successful approach using commercial microwave software to modeling of the full RF filter layout including all electrodes of interdigital transducers and gratings. We use IE3D, a MOM based software by Zeland, to model the imported layout and we use the COM method to describe the acoustic properties of the elements. We benefit from the useful meshing capabilities of IE3D in order to obtain moderate size of the problems intended for solving with ordinary PC in reasonable time. We take special care to define properly ports for combining acoustic responses obtained from carefully fitted experimental COM parameters. With this procedure we are able to predict automatically some very important features of electromagnetic interactions within electrodes used for acoustical excitation, such as coupling between transducers in DMS structures. We describe an example of a two-port resonator with a detailed comparison of all experimental and modeled responses. This work opens the way to a further reduction of uncertainty in RF filter design.