FDTD analysis of crosstalk between SAW filter and package

A RF SAW filter device is sensitive to crosstalk between package and pads on the substrate. An accurate modeling taking into account the electromagnetic effects of the pattern on the SAW substrate is thus important to the performance of the SAW device. In this paper, a full-wave approach based on the finite-difference time-domain (FDTD) method is employed to investigate the above crosstalk. Our approach has been applied to a single one-port SAW resonator and the frequency response has been obtained. The electromagnetic field distribution over the substrate and the SAW insertion loss are also shown. It is then extended to include simple packaging to reveal the crosstalk between the pad and package. Measurement is also carried out to verify the simulation results.