Glass Package for Radar MMICs above 150 GHz

This work presents a novel sensor packaging and a novel transition concept for radar applications above 150 GHz based on glass material. By using laser induced deep etching (LIDE) technology, glass vias and cavities are fabricated without degrading the mechanical stability of glass, as micro-cracks are completely avoided. Especially at high millimeter wave (mm-wave) frequencies, precise structuring on low dielectric loss materials and a high integration density are essential for low loss transitions. In this paper, an ultra compact FMCW radar monolithic microwave integrated circuit (MMIC) at 160 GHz is used to demonstrate this packaging technology. In addition, the high frequency signal is guided by a low loss transition to a deposed antenna via a dielectric waveguide (DWG) providing the antenna front end with mechanical flexibility. Thus, using plated through glass vias (TGVs) and a circulating solder ring, the package is hermetically sealed. The optical transparent glass package has a size of only 5.8\, mm× 4.4\, mm× 0.9\, mm. A minimum measured insertion loss of 2.85 dB at 162 GHz from chip to DWG is achieved. The complete radar system with a range resolution of 12 mm is demonstrated via radar measurement.