A 13th-order CMOS reconfigurable RF BPF with adjustable transmission zeros for SAW-less SDR receivers

Current cellular receivers often employ acoustic filters (SAW or BAW) for each communication band due to their high selectivity, low insertion loss, and small formfactor. The need to support multiple communication bands, multi-input multi-output (MIMO) communications, and carrier aggregation necessitates the use of several such acoustic filters with a large overall footprint. These acoustic RF filters employ several high-Q acoustic resonators to create several poles and transmission zeros in a high-order transfer function to achieve low insertion loss within a nearly flat passband, fast roll-off, and highly attenuated stopband. The low quality factor of integrated passive components, specifically inductors, leads to a significant increase of insertion loss (proportional to the filter order and inversely proportional to the component quality factor) and poor stopband rejection for an equivalent RF filter.