Coupled Resonator Filters for W-CDMA Duplexer Application

This work presents the design and the measured performances of a duplexer based on bulk acoustic wave coupled resonator filter (BAW CRF) for W-CDMA application. This device is dedicated to be integrated in a RF module for cellular phone. A co-simulation methodology between a 1D acoustic model (Mason-type) and an electromagnetic solver is developed to allow a good prediction of the filter response on a large frequency range. The minimum insertion loss for the Tx and Rx filter is better than -3 dB and the isolation between Tx and Rx ports is greater than 60 dB. The rejection of the Tx filter is better than -50 dB in the Rx frequency range and is up to -67 dB in the Tx frequency range. The CRFs handle up to 27 dBm at Tx center frequency.