Vertical Feedthroughs for Millimeter-Wave LTCC Modules

This paper reports on novel types of vertical interconnects to be incorporated inside highly integrated LTCC Modules (Low Temperature Co-fired Ceramics). RF-transitions vertically interconnecting the top and bottom side of the LTCC are studied using alternatively CPW (coplanar waveguide) or microstrip feedlines. Vertical DC supply and control lines with integrated RF blocking capacitors are also demonstrated. LTCC test modules were fabricated and the performance of all feedthroughs successfully validated by scattering parameter measurements up to 40 GHz.