Ultra-Precise Deposition (UPD) Printing for Millimeter Wave Interconnects in D-Band

This paper presents the first millimeter wave (mmW) interconnect in D-band fabricated with the ultra-precise deposition (UPD) printing system by XTPL to the best of our knowledge. To determine the interconnect performance precisely, it has been created between two coplanar waveguide (CPW) transmission lines on Alumina. The two line segments are separated by a trench in the substrate, which is filled with a polymer. It mimics the gap between an MMIC placed in a cavity and the substrate in a future package. The interconnect measurement is de-embedded using a custom TRL calibration substrate. The insertion loss was found to be 0.22 dB on average over the entire D-band for a 20 μm wide trench with an input matching of 27.5 dB on average. An additional investigation of the influence of the trench size shows that it is favorable to keep the interconnects as short as possible. Altogether, this paper demonstrates the usability of UPD printing for mmW interconnects above 100 GHz.