Optimizing Signal Integrity in 3-D Sensor Packaging Using Embedded Inverted T-Slot Shielding Structures

To address the escalating signal integrity (SI) challenges in high-frequency 3-D sensor packaging, this study proposes an embedded inverted T-slot shielding structure integrated within redistribution layers (RDLs). Unlike conventional surface-level shielding, the inverted T-slot provides 3-D electromagnetic confinement by intercepting lateral and vertical fields. Full-wave and circuit cosimulations demonstrate up to 20-dB reduction in near-end coupling ( ${S}_{{12}}$ ), with a notable 35-dB improvement in return loss ( ${S}_{{11}}$ ) and a 1.3-dB reduction in insertion loss ( ${S}_{{13}}$ ) across the 0–50-GHz band. Comparative analysis across silicon and glass substrates highlights material-dependent optimization strategies, where glass substrates yield superior impedance matching and silicon substrates achieve stronger coupling suppression. The proposed structure remains fully compatible with standard RDL manufacturing processes, offering a practical and scalable solution for high-density sensor platforms, 5G/6G transceivers, and millimeter-wave (mmWave) communication systems requiring robust SI performance.