2009 IEEE International Frequency Control Symposium Joint with the 22nd European Frequency and Time forum
DOI: 10.1109/freq.2009.5168328
Institute of Electrical and Electronics Engineers, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 3(57), p. 518-523, 2010
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In this paper we present the design, fabrication technology, and characterization of BAW filters for the Digital Cellular System (DCS) Tx-band at 1.75 GHz. The filters are fabricated with AlN-based solidly mounted resonators (SMR) using iridium electrodes, in an attempt to increase the effective electromechanical coupling factor of the BAW devices and achieve the bandwidth requirements of DCS filters. The design and optimization of the filters is performed with a simulation tool that uses a circuit model to compute the filter frequency response. Tx filters with balanced inputs and outputs and different topologies are designed and fabricated. The experimental filter response is compared with the simulations to determine the suitability of each design. DCS bandwidth requirements are fulfilled by using Ir/AlN/Ir stacks.