High quality spiral transformer embedded in LTCC substrate

This paper presents a continuance of research regarding design, fabrication and characterization of high inductance integrated passives with good performances. For that purpose a simple square spiral transformer is embedded in a stack formed from commercially available dielectric and ferrite material, with intent of inductance increase along with maintenance of transformer performance. Designed transformer is fabricated in the standard LTCC (Low Temperature Co-fired) technology and characterized. Obtained experimental results show that implementation of a very thin layer of ferrite material increases transformer self-inductance over 80 %, if compared to the same geometry realized purely on dielectric substrate. In addition, good performance (high quality factor value) of the transformer is maintained at the same occupied chip area.