Radiated EMI coupling analysis between high-speed modules and receiving antennas of mobile devices

This study mainly investigates the impact of high-speed digital modules´ radiated EMI noise on receiving performance of wireless mobile device via built-in antenna coupling. We began with designing dipole and loop antenna to represent the routing and trace pattern for common- and differential- mode current flowing inside digital modules installed in mobile devices(such as Tablet, Notebook computers, and smart phones), and then observed the coupling effect of their EMI noise on receiving antenna ports. Utilization of EMI measuring equipment described in this paper not only can obtain the interference power corresponding to the frequencies and levels of noise from device under test (DUT), we can also derive the radiation patterns related to common- and differential-mode radiation from surface scanning results. We would then further establish the relationship between the DUT characteristics and noise locations to find the optimal placement for noisy DUT and antennas. The result of this study can help to establish the preliminary noise budget for those components built in the wireless communication platforms.