Integrated Millimeter-wave passive devices based on Silicon substrate for SoP application

In this paper, a process to fabricate BCB/Au multilayer stack on low resistivity Silicon (Si) based on the embedded package structure is developed, especially for the first time spin coating of the dielectric material on the Si substrate. Transmission lines, including micro-strip transmission lines and coplanar waveguide (CPW) lines are designed, fabricated and characterized, which performs excellently: insertion loss and return loss of the standard 50 ohm micro-strip lines are less than 0.08 dB/mm and better than 32 dB/mm respectively during the band from 20 GHz to 30 GHz. Additionally, a power divider is fabricated using the thin film micro-strip lines, which applied in the front end of a traffic flow detecting radar. This power divider has such a wonderful performance, such as insertion loss less than 0.45 dB and return loss better than 25dB with an intrinsic size of 1.6 × 0.84 mm².