Dielectric compositions of magnesium titanate and devices thereof

Compositions of finely divided inorganic powders useful for forming dielectric layers in multilayer electronic structures of conductive and dielectric layers on an alumina substrate;

• those dielectric layers being capable of producing such multilayer structures having a dielectric constant below 10 and a dissipation factor of 0.6% or less, each at 1 kHz., and a quality factor above about 400 at 1 MHz.;
• the compositions consisting essentially of, by weight,
• a. 65-90% of one or more non-conducting glasses having a softening point greater than 700.degree. C. and a thermal expansion coefficient less than that of alumina, and the balance is
• b. 10-35% of crystalline fillers which are, based on the total weight of the composition,
• 1. 0-25% MgTiO.sub.3 and/or
• 2. 0-35% mixtures of precursor crystalline oxides MgO and TiO.sub.2 capable of forming MgTiO.sub.3
• provided that where the weight of MgTiO.sub.3 in these compositions is less than 10%, the relative proportions of precursor crystalline oxides (2) are such that in the fired dielectric layer(s) in the aforesaid multilayer electronic structure(s) there will be a total of at least 10% MgTiO.sub.3, and further provided that the relative proportions of precursor crystalline oxides are such that in the fired dielectric layers there will be no more than 25% MgTiO.sub.3.