A study for grounding effect to improve performance of WWAN

Electromagnetic interference (EMI) from a LCD panel deteriorates the performance of wireless network system (with wireless network cards: Wireless Wide Area Network (WWAN) card) in a notebook. One of the main EMI noise factor, for the wireless network system, is the grounding effect of the antenna in the system. In this paper, the approach to solve the EMI noise of the system is introduced; by using the grounding methods of the system. In order to measure the EMI noise of the WWAN itself, the standard JIG system is developed. Most grounding effects are confirmed experimentally. Because the EMI noise of the WWAN system is difficult to reduce, it is important to know the antenna (with the coaxial cable) itself.