Optimization of BAW resonator performance using combined simulation techniques

Abstract

Filters based upon bulk-acoustic-wave (BAW) resonators are attractive for a variety of RF applications. To master the ambitious specifications and to facilitate a fast and cost economic design, we present an efficient simulation strategy combining different modeling approaches. As the first step, a 1D transmission line model (Mason model) is used for constructing the layer stack to meet the desired resonance frequencies and bandwith. Second, the system of Newton’s equation of motion and Maxwell’s equations coupled by the piezoelectric effect is solved by FEM simulations. Thus, the lateral structure, e. g. specific border regions, can be designed to maximize the Q factor and to minimize the excitation of spurious modes. The theoretical predictions are excellently confirmed by experimental results.