Intrinsically switchable ferroelectric bulk acoustic wave filters based on barium strontium titanate thin films

Abstract

Single-standard wireless transceivers are of limited use as multi-mode devices become ubiquitous. Adaptive and reconfigurable RF circuits are necessary to decrease size, cost, and power consumption as well as increase reliability and robustness of wireless devices. In this paper, the design, fabrication, and performance of acoustically coupled and electrically coupled filters based on the ferroelectric barium strontium titanate are discussed. In their off state, the input and output ports are isolated from one another. When switched on with the application of a dc bias voltage, a bandpass filter response is obtained.

Tight-coupled microstrip hairpin bandpass filter

“…On the other hand, the lumped filters are not implemented for narrow bandwidths and can cause unpredictable behavior at higher frequencies (G.T. Bharathy et al, 2019).Apart from lumped filters, intrinsically switchable ferroelectric bulk acoustic wave filters based upon BST (Barium, Strontium Titanate) material provides a compact and low tangent loss circuit designs, which would allow this filter to be used in reconfigurable radio designs (Victor Lee et al, 2013).The advantage of this type of filter is that if the resonators places are precisely determined, then the filter can have a wide bandwidth and low S11 parameter (Victor Lee et al, 2013).On the other hand, the insertion loss and return loss parameters depend highly on the geometry and separation distance between resonators and as such would be highly affected if the simulations were done inaccurately. Furthermore, if the design requires more simulations prior to manufacturing, then it can be argued that the designing with given technology would be time consuming.…”