Oxide thin films for tunable microwave devices

Oxide thin films have been studied for frequency and phase agile electronic s. The electric-field tuning of microwave devices employs ferroelectrics, w hile the Magnetic-field tuning uses ferrites. The critical material paramet ers for ferroelectric thin films are the tunability of the dielectric const ant and the dielectric loss. This paper describes the current understanding of the fundamental mechanisms of these properties and the research efforts to improve them in ferroelectric thin films.