Hybrid Active-Passive Beamforming for Scalable sub-Terahertz Antenna Array

For massive multiple-input multiple-output applications in sub-terahertz band, both active and passive beamforming methods encounter challenges. This paper proposes a concept of hybrid active-passive beamforming using a combination of both to address the issues. We also introduce an implementation platform using glass interposer with patch antenna array on polymer build-up layers and integrated-circuit chips embedded in the glass core.