Influence of various multilayer LTCC systems on dielectric properties’ stability in GHz frequency range

Abstract

Purpose The purpose of this paper is to create multilayer substrate (composite) from various low temperature co-fired ceramic (LTCC) substrates by their mutual combinations and to analyse influence of these multilayer substrates on dielectric properties in GHz frequency range. Design/methodology/approach GreenTape 951, GreenTape 9K7 and Murata LFC were used to create compound multilayer substrates that include three layers: middle layer is from Murata LFC, and both upper and bottom layers are either from GreenTape 951 or GreenTape 9K7. Shrinkage in all x-, y- and z-axes of all substrates including multilayer substrates were analysed, and influence of different shrinkage on dielectric properties was examined by microstrip ring resonators applied on all mentioned of substrates. Findings The middle layer of Murata LFC has significant influence on shrinkage value of composites which has a good repeatability and minimalizes problems with design of multilayer LTCC devices. Impact of middle layer from Murata LFC on dielectric constant is not significant, but on the other hand Q factor (loss tangent) of these composites is increased according to inhomogeneity between single LTCC layers, especially at frequency around 6 GHz. Originality/value The novelty of this work lies in creating multilayers systems from different types of LTCC substrates to find combination with the most suitable physical and dielectric properties for various purposes in GHz range applications.