Special glass for packaging of high frequency electronics

Glasses have advantages in RF applications due to their smooth surfaces and their excellent homogeneity. The advantages of glass become more important in the range of mm-waves for frequencies above 30GHz. In the current paper we discuss the properties of a new glass which is in particular suited as a substrate for high gain, high bandwidth mm-wave antennas and filter structures. The new glass, which we call in theis work SCHOTT 8325, has a dielectric loss which is lower than the dielectric loss of standard alkaline free glasses by a factor of 3, and has a low dielectric constant of
$\epsilon^{\prime}=4$
. We discuss the applicability of such a glass for mm-wave antenna and filter applications and show measured data of the dielectric loss for frequencies up to 110GHz. The material shows a Qf value of around 18000 GHz at high frequencies.