Glass Ceramics: An Alternative Substrate for Microwave Integrated Circuits Available to Purchase

This paper presents the results of an investigation into alternative substrate materials to alumina and the associated techniques necessary to utilise them in microwave integrated circuits (MICs). The major driving force for this work was to reduce MIC processing costs without significantly degrading the RF performance. Different glass ceramic systems were assessed and 6–18 GHz gain modules were produced on the most promising of these materials. One glass ceramic material, CMA6, with a dielectric content of 6 • 4, showed a comparable measured gain to that obtained for alumina circuits between 6 and 15 GHz. Cost analysis indicated that, with the reductions in material costs and yield improvements on using glass ceramic substrates, a cost saving of approximately 12% per module is feasible.