Coplanar waveguide ferroelectric thin film microwave phase shifters

Abstract

Ferroelectric thin film, such as barium strontium titanate (BaxSr1-xTiO3 or BST), has shown great promise for the fabrication of tunable RF and microwave components. An important tunable microwave device using ferroelectric film is a wideband phase shifter which is the most important component of the phased array antenna. Phase shifters with low insertion loss, low drive power, proper power handling capability, continuous tunability, good impedance match, fast response speed, and low production cost are the key to the development of lightweight phased array antennas. This chapter looks at microwave phase shifter applications of ferroelectric thin films. It starts with the introduction of microwave phase shifter and coplanar waveguide transmission lines, with emphasis laid on the significance and applications of ferroelectric materials. The basic theory of distributed transmission line phase shifters is then discussed. The physical layout design, device fabrication, and microwave characterization of distributed coplanar waveguide transmission line phase shifter using ferroelectric thin film varactors with parallel-plate electrodes are presented in the final two sections. © 2012 by Nova Science Publishers, Inc. All rights reserved.