Ba1−xSrxTiO3 thin-film-based X-band selective coplanar waveguide microwave resonator using SiO2 as buffer layer

Open-circuited coplanar waveguide (OC-CPW)-based filters have many applications in microwave and transmission line circuits. CPW-based resonant structure with ferroelectric thin film provides advantages including small size, light weight, tunable frequency, etc. The purpose of the current work is to fabricate the novel design of X-band (8.2–12.4 GHz) microwave resonator on thin film of Barium Strontium Titanate (Ba0.5Sr0.5TiO3 or BST) on bare silicon (Si) substrate with and without silicon dioxide (SiO2) as buffer layer. The pattern of microwave resonator has been successfully designed using conventional UV-photolithography technique on Pulsed Laser Deposition (PLD)-grown thin films of BST. The resonating frequencies with minimum return loss of devices fabricated on BST/Si and BST/SiO2/Si substrate recorded as 7.8 GHz and 10.02 GHz, respectively. The resonating frequency of microwave resonator on BST/SiO2/Si substrate lies in X-band region. OC-CPW microwave resonator on (a) BST/Si and (b) BST/SiO2/Si OC-CPW microwave resonator on (a) BST/Si and (b) BST/SiO2/Si