Platform Interference in Wireless Systems

Intra-system EMC problems are becoming increasingly common in mobile devices, ranging from notebook PCs to cell phones, with RF/wireless capbilities. These issues range from minor annoyances to serious glitches which impede the functioning of the device. This book gives a thourough review of electromagnetic theory (including Maxwell's equations), discusses possible sources and causes of intra-system interference, shows to use models and analysis to discover potential sources of intra-system EMC in a design, how to use appropriate tests and measurements to detect intra-system EMC problems, and finally extensively discusses measures to mitigate or totally eliminate intra-system EMC problems. With more and more mobile devices incorporating wirless capability (often with multiple wireless systems, such as Bluetooth and WiFi), this book should be part of the reference shelf of every RF/wireless engineer and mobile device designer.

Addresses a growing problem in RF/wireless devices----interference created inside the devices, which impair their operation Covers devices, ranging from laptop PCs to mobile phones to Bluetooth headsets *Explains the sources of such intra-system interference, how to detect and measure such interference, design techniques for mitigating the interference, and proven techniques for eliminating the interference

RF/Wireless Engineers; Mobile Device Designers

Chapter 1: Introduction Describing the problem The Radio Channel Platform emissions impact on a radio receiver Platform to radio isolation requirements Platform RF snapshots 3 meter measurements Platform RF as seen at the radio front end Broad-band measurements in the near field Desktop and notebook platforms Small form factor platforms System components as noise sources Platform RFI sources- Summing it up

Section 2: Platform Signals Chapter 2: The Structure of Signals Harmonic variation with time Signal Asymmetry Variation with duty cycle Non-repetitive signals Spread spectrum clocks Data sequences as signals The impact of equalization Platform display symbols The spectrum of complex symbol sequences Time structure of symbols Comparison of PRBS, clock and symbol sequences

Chapter 3: Analysis of Symbols Ordering finite symbol sets for RFI Wireless performance in the presence of display symbols Measuring interference impact Analysis of differential symbols Signal structure jitter and the impact on EMI and RFI

Section 3: Measurement and Models Chapter 4: Measurement Methods Measurement methods, near field scanning Fields in dielectrics Locating system sources of interference Near field scans of clock ICs Energy flow in the near field and the transition to the far field Broad-band measurements with a horn antenna Measurements with the GTEM cell Far field measurements using anechoic chambers Reverberation chambers

Chapter 5: Electromagnetics Electromagnetic units Maxwell’s equations for the static condition Maxwell’s equations for the time varying condition The electric scalar potential The magnetic scalar potential Radiation mechanisms Chapter 6: Analytical Models The elementary electric dipole The field impedance of the electric dipole The extended dipole model Measured near fields over silicon Building a model of the radiation surface of multiple sources The magnetic dipole Building system models using PCI Express Comparing model and measurement

Chapter 7: Connectors, cables and power planes Power Distribution Radiated Emissions Further investigations with various power topologies Chapter Summary

Section 4: Mitigation Techniques Chapter 8: Passive Techniques Introduction Passive Mitigation Shielding Absorbers Layout Chapter 9: Active Mitigation Frequency Planning Controlling Frequency Content Radio Improvements Appendix A: Appendix to Chapter 2 Appendix B: Appendix to Chapter 3 References