The rapid development of ultrabooks in recent years, manufacturers position the two WLAN antennas beside the keyboard and motherboard as shown in Figures 1 and 2 because the display panel is too thin for the antennas to be installed. On top of that, with the development of the USB 3.0 super-speed technology, there are more and more laptops with USB 3.0 ports installed in them. Unfortunately, if the USB dongle is plugged in, it radiates the noise power (in the 2.4–2.5 GHz range) that affects the functionality of WLAN antennas in the ultrabooks because the antennas are so close to the USB 3.0 modules. This noise can radiate from the USB 3.0 connector on a PC platform, the USB 3.0 connector on the peripheral device or the USB 3.0 cable. This can result in a dramatic drop in throughput on the wireless link.

In fact, not only do the USB 3.0 modules affect the wireless LAN antennas but also HDMI, LVDS, SATA, PCI Express, and display port…etc have an impact on the WLAN antennas in ultrabooks. The impact of the USB 3.0 super-speed modules on RF wireless communications is a significant problem that computer system manufacturers are facing. With the new Microsoft Windows 8 in the next generation and the development of Windows-To-Go technology as shown in Fig. 3, the Win8 USB dongle, when plugged in, can limit the sensitivity of the WLAN antennas in ultrabooks.

To understand how the USB 3.0 modules affect the WLAN antennas, and quantify the effects of the USB 3.0 noise power on the WLAN antennas in ultrabooks, experiments have been conducted, inclusive of the measurement of the WLAN antennas’ throughput rate, and the measurement of the amount of the noise power received by the wireless LAN antennas. Equipments such as Microwave Power Clamp, System Noise Analyzer (SNA), Noise Floor Measurement System (NFS), and Platform Noise Scanner (PNS) have been developed to help our clients with their critical R&D stage by minimizing platform noise and maximizing RF performance.