Design of the PCB embedded active IC structure for ultra-thin wearable application with low-RFI

Abstract

The ultra-thin design is essentially required for mobile and wearable applications, while the multiple operations are needed to be integrated in tiny space of the product. For achieving ultra-thin design and low radio-frequency interference (RFI) characteristics, the PCB embedded active IC structure was proposed in previous studies. However, there were limitations for fabricating the structure: One is difficulty to test, the other is high cost of the process, and the other is still exposure to RFI. In this paper, we propose the structure that can be fabricated by using normal PCB process with an anisotropic conductive film (ACF) bonding. The structure, which we propose, can overcome the limitations of the previous PCB embedded active IC structure. Among limitations, RFI could be effectively reduced by noise field reduction of radiation and conduction. The shielding effectiveness is key factor for reducing radiated field coupling, and signal integrity (SI) and power integrity (PI) factors, such as crosstalk and PDN mode resonance is critical factor for reducing conducted field coupling.