Multifunctional Ferroelectrics based Devices for Next Generation RF Front-ends

Wireless communications, now within its fifth generation (5G), aims to attain connectivity across billions of devices, transcending geographical barriers and fostering advancements across various domains, such as healthcare, manufacturing, and transportation. However, this advancement presents challenges, notably the necessity to accommodate for numerous radio frequency (RF) bands. Moreover, there is further development toward incorporating millimeter-Wave (mm-Wave) frequencies for high-speed communication. Current RF front-end designs, already complex with over 100 filters and switchplexers, encounter limitations in accommodating these new frequencies within the confined space of mobile devices, demanding innovative solutions.

Towards addressing RF acoustics limitations in front-end architecture, this dissertation presents resonator and filter designs employing two different multifunctional ferroelectric materials: Barium Strontium Titanate (Ba_xSr_1-xTiO₃, BST) and Scandium Aluminum Nitride (Sc_xAl_1-xN, ScAlN). For BST, a number of electrostrictive based reconfigurable filters are presented, which could significantly reduce the size, cost, and complexity of the RF front-end. For ScAlN, a promising and commercialized material for bulk acoustic wave (BAW) technology, a mm-Wave acoustic resonator that overcomes current limitation of frequency scaling in modern RF acoustics is designed and fabricated.

CHAIR: Professor Amir Mortazawi