Design criteria of solidly mounted thin film bulk acoustic resonator

Solidly mounted thin film bulk acoustic resonator is a major part of study of filter because it could be used in high frequency range and the manufacture is easy. Reflection layer,consists of periodic structure,is a significant condition of this kind of resonator,because it could keep acoustic energy in piezoelectric layer.So the design of periodic structure of reflection layer is a factor of development of this kind of resonator.
Attenuation coefficient is the major control of energy distribution of one dimensional periodic structure.The first band gap width of infinite periodic structure is directly related to attenuation coefficient.However,the attenuation coefficient of finite periodic structure couldn