Monolithic above-IC resonator technology for integrated architectures in mobile and wireless communication

This paper demonstrates the feasibility of an above-IC bulk acoustic wave technology for wireless applications. A double-lattice bulk acoustic wave (BAW) filter with balanced input and output has been designed and integrated as a post-process directly above 0.25 μm BiCMOS wafers comprising RF circuits. This filter, featuring moderate insertion loss of -3 dB and extreme out-of-band rejection (> -50 dB) is used in a simplified RF front-end receiver for the WCDMA standard, as well as in a new type of filtering LNA comprising two broadband amplifiers and one BAW filter.