MMIC-to-Dielectric Waveguide Transitions for Glass Packages Above 150 GHz

In this work, novel concepts of an electromagnetically coupled transition and a galvanically coupled transition in glass technology are presented. This enables efficient coupling of signals above 150 GHz into a dielectric waveguide (DWG). Laser-induced deep etching (LIDE) technology provides fabrication of glass holes, cavities, and cutouts with a precision suitable for use in highly integrated mm-wave modules. Based on the package concept presented by Galler et al. (2022), this article introduces an ultracompact galvanically isolated transition from monolithic microwave integrated circuit (MMIC) to a mechanically flexible DWG, offering a minimum insertion loss of 2.95 dB. The simple fabrication provides a cost-effective variant for modern system-in-package solutions. In addition, a galvanic through-plating of the glass cover with through-glass vias (TGVs) and a ring slot structure for the excitation of a DWG are presented. Thereby, the integration density and performance can be further increased. A minimum insertion loss of 2.62 dB within a large 1-dB bandwidth of 18 GHz around the operating frequency of 166 GHz is verified by measurement. Both the transitions cover a high integration density, hermetic sealing, and modular use suitable for requirements of today's modern radar and communication packages.