Advanced microwave acoustic filters enabling advanced system concepts

This paper will discuss different concepts for the RF front-end of cellular phones which comprise quad band GSM and triple band WCDMA operation. Different system concepts require filters which meet different specifications. We will show a microwave acoustic duplexer that fulfills all these requirements and thus enables advanced system concepts. It will be shown that the combination of BAW (bulk acoustic wave) and SAW (surface acoustic wave) filters within a duplexer for WCDMA exhibits excellent performance and allows to eliminate the interstage filter in the Rx path.