MoL analysis of the mechanical behaviour of acoustic mirrors

Bulk acoustic wave (BAW) resonators are widely used, as they possess superior features when used as filters. BAW devices are less lossy and capable of more power handling in comparison to their rivals like discrete and SAW filters. They comprise of one active, piezoelectric layer, which is mounted on an acoustic isolated platform, that could be either a floating thin membrane or an acoustic mirror. Later - acoustic mirror - is an interleave of low and high acoustic impedance layers each with the length of λ/4. In today competitive and tight market a thorough analysis of any MEMS device is mandatory before manufacturing to inhibit extra cost of primary engineering mistakes. In this paper we employ a numeric techniques called Method of Lines (MoL) to model the mechanical behavior of the layered acoustic mirror structure. As the MoL is very efficient in simulating the EM properties of a layered topology, with a combination of both approaches a BAW resonator can be fully described. In this paper only the mechanical part is treated, its benefits and problems are described.