Appropriate Methods to Suppress Spurious FBAR Modes in Volume Production

Standards like CDMA in combination with the US PCS band impose challenging demands on the duplexer unit in the RF circuit of mobile phones. FBAR filters are candidates to fulfil the latest cutting-edge requirements for temperature stability, insertion loss, power durability, bandwidth, and filter skirts. Unfortunately, these filters suffer from spurious resonator modes. In this work we have investigated several suppression methods, which are capable of being applied to volume production