Analysis of RF Signal Interference Invasion Into Hard Disk Drive System and Coupled to Read Front-End System

Disk drives' high data rate frequencies now occupy the same radio-frequency (RF) signal frequency bands of wireless communication networks. RF signals invade into the disk enclosure (DE) through the hard disk drive's slots, which are created by the gap between the top cover and the base between screws. Poor immunity DE designs allow wireless RF signals to interfere with the low-amplitude read signal of the customer's data. It is important to find the invasion path of the RF signal interference, and to apply the countermeasure to improve RF immunity. To determine the best configurations for RF immunity from a slot to the read path, this paper compares the RF immunity among four kinds of signal-trace suspension configurations by two kinds of extrinsic RF coupling measurement methods. Analysis shows that proper ground routing of some signal return traces can significantly improve RF immunity, and electrostatic discharge protection.