Fabrication and performance of coplanar ferroelectric phase shifter

Abstract

Coplanar ferroelectric phase shifters have been fabricated from thin films of barium strontium titanate (BST) and gold coplanar waveguide. The ability for these devices to provide a variable phase shift is based upon the change in dielectric constant of the BST with an applied de bias. We have fabricated coplanar phase shifters by three different series of fabrication steps. For each of the three devices, MgO was used as the substrate, and the BST films were deposited by laser ablation. We describe the coplanar design, material deposition, and the high frequency testing. The phase shifters were tested at frequencies up to 35 GHz.

Key Words:

• Ferroelectric
• thin films
• phase shifter