Tunable Filters? Reality Check Foreseeable Trends in System Architecture for Tunable RF Filters

摘要

The perpetual challenge of multiband/multistandard RF solutions for smartphones is to pack additional bands into the same footprint while also improving performance from one generation to the next. Are tunable filters the answer? No, not anytime soon. This article reviews leading trends in the RF front end of smartphones and provides a summary of realistic requirements for a hypothetical tunable RF filter to cover multiple bands and thus displace both switches and regular filters/duplexers. It also reviews the changes in system architecture required to address long-term evolution (LTE) carrier aggregation (CA).