High rejection Rx filters for GSM handsets with wafer level packaging

We present results of PCS and DCS Rx filters based on thin film bulk acoustic resonator (FBAR) technology for GSM handset application. The typical minimum rejection performances for PCs Rx filters are >18dB in the band of 1830-1910 MHz and 2010-2070 MHz, and >29 dB outside of the 1830-2070 MHz range. The typical minimum rejections for DCS Rx filters are >18 dB in the band of 1705-1785 MHz and 1820-1980 MHz, and >29 dB outside of the 1705-1980 MHz range. The filters consist of seven FBARs electrically coupled in a ladder topology, and are hermetically sealed using wafer-level packaging. The die sizes of PCs and DCS Rx filters are 0.7×0.8×0.25 mm and 0.9×0.9×0.25 mm, respectively.