Reconfigurable Transfer Function BST Acoustic Wave Lumped Element Resonator Filters

This paper reports on the design, manufacturing and testing of intrinsically-switchable ferroelectric barium strontium titanate (Ba
(x)
Sr
(1-x)
TiO
3
, BST) acoustic-wave-lumped-element (AWLR)-based RF filters. For the first time, we demonstrate RF filters with unique reconfigurable transfer function characteristics (all-pass-to-bandstop response and bandpass-to-all-reject response), enhanced fractional bandwidth (FBW), i.e.> kt
²
and operational frequencies as high as 2 GHz. The reconfigurable filter prototypes are directly integrated onto the Si wafer after BST thin film growth and are able to reconfigure their filtering response through application of a DC bias voltage.