A low-temperature cofired ferroelectric ceramic composition for electrically tunable radio frequency devices is introduced. A sintering temperature of 950degreesC for BaSrTiO3,-MgO was obtained following the combined addition of B2O3 and Li2CO3.The effects of these sintering aids on densification, microstruc-ture, and ferroelectric properties were investigated. The permittivity and dissipation factor values were 234 and 0.0010, respectively, measured at 286.3 K, 1 kHz. The electrically tunable ferroelectric structure for microwave measurement was fabricated throughout the tape-casting process. Measured permittivity was 130 at 26 GHz and tunability >15% (4 V/mum).