Investigation and Mitigation of Radio Frequency Interference Caused by Weak Grounding of USB Type-C Receptacle Connector

In modern mobile electronic systems, USB connector has been identified as one of the dominant noise sources for desense issues. In this paper, the noise coupled to the Wi-Fi antenna from a USB connector is investigated. With the assistance of full-wave simulations, the root cause of desense noise is identified as the non-ideal electrical connection between the metal chassis and the USB receptacle shell where it is installed. The proposed radiation mechanism is validated through measurements of a real tablet device, and 15 dB noise level reduction is observed with a better grounding structure.