Development of Compact Millimeter-Wave Antenna by Stacking of Five Glass Wafers With Through Glass Vias

This letter proposes a high bandwidth compact linear polarization antenna for the automotive radar millimeter-wave band of 77 GHz using five stacked glass layers scheme with high precision metal layers and through glass vias (TGVs). The radiation part of antenna is composed of four microstrip patches, wherein a single patch is only$0.55\times0.55$mm2, and the overall size of the package is 10$\times 9\times $1 mm3. 6-inch glass wafers with the thickness of$230~\mu $m or$100~\mu $m are employed to achieve high-density interconnects and precise manufacture. The interconnects formed by the TGVs and redistribution layer (RDL) realize direct transmission and signal coupling between layers to improve transmission efficiency. The gain is more than 7 dB at frequency of 77 GHz. This proposed glass Antenna shows the superior advantages of process accuracy to realize miniaturization and System in Package (SiP) compared with that of Low-Temperature Co-fired Ceramics (LTCC) and Printed Circuit Board (PCB).