Coplanar Phase Shifters Based on Ferroelectric Thin Films

Abstract

Barium strontium titanate (Ba 0.6 Sr 0.4 TiO 3 , short for BST) thin films were prepared by RF-magnetron sputtering. The dielectric tunability, loss tangent, remanent polarization (2Pr) and coercive electric field (Ec) of the BST films are respectively 29.5%, 0.013, 2.29 μC/cm 2 and 22.27 kV/cm at 1 kHz and 20 V. The designed coplanar waveguide (CPW) phase shifter consists of 56 same sections. It is shown that the fabricated lines of electrodes are smooth and the widths at the tip of bottom electrodes are about 5 μm. At the central frequency of 28 GHz and a bias voltage of 20 V, the figure of merit is approximately 13°/dB.

Effects of interface on the dielectric properties of Ba0.6Sr0.4TiO3 thin film capacitors

“…Polycrystalline barium strontium titanate (Ba x Sr 1Àx TiO 3 , short for BST) thin films are potential materials for the applications of microwave devices such as dielectric phase shifters and tunable filters due to their excellent dielectric properties such as high dielectric nonlinearity, low leakage current, long lifetime, large dielectric breakdown voltage, good temperature stability and adjusting Curie temperature [1][2][3][4][5][6].…”