Module, antenna, and package design considerations for mm-scale IoT devices

This paper presents a study of antenna-in-package (AiP) design options for mm-scale Internet-of-Things (IoT) applications. Specifically, silicon interposer and organic-based substrates with areas ranging from 2.1x2.1 mm(2) to 6x5 mm(2) are explored as options to package a mm-scale active IoT IC and integrate it with antennas to form a compact module capable of power harvesting and data transmission. The AiP designs considered are electrically-small loop and dipole antennas operating at 900 MHz and 5.8 GHz in the sub-6 GHz bands as well as dipole antennas operating in the 28 GHz mm-wave band. Simulation results show that AiP designs in both silicon interposer and organic-based substrates can achieve similar performance; moreover, we also observed that for a given EIRP limit, 28 GHz achieves the highest range for smaller 2.1x2.1 mm(2) substrates. Initial measurement results on fabricated AiP test structures and complete IoT module samples show the feasibility of electrically-small antenna designs for these applications and highlight associated fabrication, assembly, and measurement challenges.