Oxide Thin Films for Tunable Microwave Devices

Oxide thin ®lms have been studied for frequency and phase agile electronics. The electric-®eld tuning of microwave devices employs ferroelectrics, while the Magnetic-®eld tuning uses ferrites. The critical material parameters for ferroelectric thin ®lms are the tunability of the dielectric constant 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 ®lms.