Circulator Integrated in LTCC with Screen Printed Co-Firing Ferrite for Space Application

A three-port junction ferrite circulator in Low-Temperature Co-fired Ceramics (LTCC) technology has been designed, fabricated and measured for applications of compact T/R modules in satellite payloads. Specifically, the co-fire-able ESL 40012 ferrite material is dissolved by alcohol and screen printed on Ferro A6ME tapes. The fabricated circulator operates at Ku band and the insertion loss is about 1.5 dB with the isolation higher than 15 dB. Since the screen printed ferrite is relatively thin and occupies small area, it reduces the stress of different materials' shrinkage mismatch during the co-firing. In addition, the fabrication is fully compatible with the conventional LTCC fabrication process. In this article, the circulator's design, the innovative fabrication process and the measurements are reported.