3.9 LOOKING AHEAD

Chapter 4 examines RF propagation and explains how reflection, diffraction, absorption, fading, and multipath can change a modulated field as it travels. These effects help explain why field strength and exposure can vary substantially with location even when transmitter output remains stable.

Chapter 5 then relates transmitter output to antenna gain, polarization, radiation pattern, and the spatial distribution of RF fields. Chapter 6 applies peak, RMS, average-power, and duty-cycle concepts to emissions, exposure, and dose, providing the foundation for the biological, assessment, and standards chapters that follow.