Antenna Array on Glass Interposer for 6G Wireless Communications

This article demonstrates integrated packaging solutions for antenna components in D-band by using a glass-based package. We design sub-terahertz (sub-THz) patch antennas at 140 GHz frequency band using HFSS simulation and form arrays of patch antennas for 6G (sub-THz) wireless communication applications. The patch antennas and feeding networks are implemented using microstrip structures on the top of the interposer, with ground planes beneath. Build-up layers of dry polymer films are laminated on a glass core for multilayer copper metallization, and copper structures are patterned on the polymer layers. For precise fabrication of the antenna and feeding structures in a package, we implement the semi-additive patterning (SAP) process to deposit the copper structures. Adequate measurement methods are applied to address difficulties in $D$ -band antenna measurements. By forming patch antenna arrays, we obtain 10 dBi gain using a four-element linear array and 14 dBi gain using a 4-by-4 2-D array. The bandwidths achieved for these arrays are 7% (10 GHz) and 5% (7 GHz), respectively, based on return loss measurements. Overall, the measurement results present a good match to the simulation. Antenna structures on glass substrates demonstrated in this article represent the basic building block for heterogeneous integration of $D$ -band front-end module (FEM) in glass-based package.