Design of FBAR filters at high frequency bands

This article presents a study about the design of film bulk acoustic wave resonator (FBAR) filters at higher frequency bands. FBAR filters are expected to replace traditional filter technologies (SAW and ceramic). This is mainly due to their compatibility with silicon low-cost process, enabling mass production and filter integration on above-IC processes. Nonetheless, increasing the operation frequency of FBAR filters, new acoustical and electromagnetic constraints are introduced to the filter design. These new constraints of designing of FBAR filters are presented. Further, a design technique using higher harmonic modes is addressed. This technique enables the realization of FBAR filters for operation at higher frequency bands (X, Ku, K, and Ka) using the same fabrication conditions of FBAR filters in L, S, and C bands.