RF filters and diplexers for wireless system applications: state of the art and trends

This paper provides an overview of the current and emerging filter technologies for wireless system applications. Detailed comparisons are given for the various filter technologies used in both base-station and mobile handsets applications. Coaxial, dielectric resonator (DR) and high temperature superconductor (HTS) technologies are addressed for base-station applications while ceramic, multiplayer dielectric, surface acoustic wave (SAW) and film bulk acoustic resonator (FBAR) filters are considered for mobile handsets applications. The current development efforts in each filter technology area are also highlighted.