This paper presents a broadband microwave vertical transition structure suitable for System on Package (SOP) applications at millimeter-wave frequencies (mmW). The designed structure includes a Microstrip (MS) to Stripline (SL) back to back vertical transition optimized for 60 GHz applications but also suitable for E-band frequencies as well. The mmW transition presented here was fabricated in a Low-Temperature Co-fired Ceramic (LTCC) process using commercially available Ferro A6M tape layers. Design and optimization of this microwave transition was carried out in order to maintain a constant characteristic impedance over the entire bandwidth. A bandwidth improvement of 30% is observed by optimizing the ground via fence of the vertical transition. A maximum of 12 surrounding vias were used due to limitations in the LTCC process. Measurements of this vertical transition show a Return Loss of better than 10 dB for frequencies as high as 90 GHz while maintaining an insertion loss of less than 0.9 dB. A grounded coplanar waveguide (CPWG) to MS planar transition with good electrical performance for up to 110 GHz was also designed and implemented to characterize the vertical transition fabricated.

13th European Microwave Week 2010, EuMW2010: Connecting the World - 40th European Microwave Conference, EuMC 2010

Amaya, R, Li, M. (Ming), Hettak, K. (Khelifa), & Verver, C.J. (Cornelius J.). (2010). A broadband 3D vertical microstrip to stripline transition in LTCC using a quasi-coaxial structure for millimetre-wave SOP applications. In European Microwave Week 2010, EuMW2010: Connecting the World, Conference Proceedings - European Microwave Conference, EuMC 2010 (pp. 109–112).