**4. Platform noise coupling mechanism**

The interfering noise sources mentioned above may introduce adverse noise to the nearby wireless modules via conduction or radiation coupling or even both. The digital noise coupled from broadband digital or narrow-band RF devices may result in in-band interference and further degrade the performance of wireless communications, and vice versa. Since the digital noise would cover a wide range of frequency, we will illustrate in Figure 18 and 19 the three potential coupling mechanisms between the noise sources and victim circuit or module: conducted coupling, crosstalk coupling, and radiated coupling.

Fig. 18. Different coupling mechanisms.

Fig. 19. Illustration of possible noise coupling for wireless device.

The Figure 20 illustrates the EM interaction between TP and embedded antenna, and the photograph of Figure 21 shows the DCS1800 and PCS 1900 transmitted power coupled to LCD panel.

Fig. 20. EM interaction between TP and embedded antenna.

Fig. 21. Illustration of DCS1800 and PCS 1900 coupling to LCD panel.
