Improved Temperature Stability of Microwave Properties in Tunable Devices Using Substituted Ba 1? x Sr x TiO 3

An improvement in ferroelectric device technology has become possible through optimization of the properties of the ferroelectric materials used to make the devices. The improvements discussed herein impact true time delay line and phase shifter performance by enhancing control over dielectric constant and extending the temperature range of tunability and device operation. Figures of merit were obtained for substituted-Ba 1 m x Sr x TiO 3 materials which have lower, less varying dielectric constant and adequate, less varying tunability at 1 MHz over the mil spec ( m 50 °C to 100 °C) range. For the sample whose figure of merit varies the least, dielectric constant and losses at 20 GHz and room temperature are reported. Dielectric constant and losses at 1 kHz are discussed.