The present and future trend of RF filters for mobile phones made of piezoelectric materials

Abstract

Recently, SAW filter and FBAR filter, both made of piezoelectric material, are widely used for RF filters of cellular phones. Both filters have many features such as small size, low-cost, and sharp cut-off characteristics which are suitable to cellular phone terminals. On the other hand, each filter has its inherent features and co-exists in the market. In this report, the structures of SAW filter and FBAR filter in contrast and the difference of characteristics and applications will be presented. The future trend of both filters will be also described.