A glass ceramic including an alkali metal earth oxide, e.g. SrO suitable for overmolding a RF component provides a good RF response and good mechanical robustness. Specifically, SrO reduces the flow temperature of the ceramic while maintaining the RF and mechanical performance. The resulting glass formulation contains 10-50 mol % SrO, 5-30 mol % Al2O3, and 20-60 mol % B2O3.