Fast Analysis of Border Ring Suppression on BAW Resonators

A procedure based on the Transmission Line Matrix (TLM) method is used to model Bulk Acoustic Wave (BAW) resonators. TLM method was successfully used to model BAW resonators with an homogeneous electrode. In this work, the method is expanded to resonators with discontinuities in the electrode, like the Border Ring. The method discretizes the lateral dimension of the BAW resonator and connects dispersive transmission lines between each node. These transmission lines are assembled into an Y-matrix. This Y-matrix is solved to obtain the field patterns on the electrodes, from which the input impedance of the resonator is calculated. The method is demonstrated capable of modelling the spurious modes suppression and the Border Ring fundamental mode.