Implementation of Ba_0.6Sr_0.4TiO₃‐ZnO‐B₂O₃ based tunable microwave phase shifters in LTCC technology

Abstract

Tunable dielectric Ba0.6Sr0.4TiO3‐ZnO‐B2O3 thick‐films were analyzed regarding their integration potential into the LTCC technology. Therefore, tunable loaded line phase shifters based on metal‐insulator‐metal varactors with single‐ and double‐printed BST thick‐films were fabricated and co‐sintered inside a four layer LTCC module. Microstructural and chemical investigations showed a sufficient compatibility and adhesion between the silver, BST composite and LTCC layers and a resulting morphology depending on the processing route. The microwave characterization of the LTCC‐embedded phase shifters revealed comparable results to phase shifters with the same design on alumina substrates.