Multipath is the phenomenon in which a signal arrives at the receiving antenna by two or more distinct paths. Which option best reflects this definition when placed among distractors?

• A. A signal travels along a single path.
• B. The signal is degraded by atmospheric conditions only.
• C. A signal arrives at the receiving antenna by two or more distinct paths.
• D. The receiver uses multiple frequencies to obtain data.

Answer: (C)

Multipath means a radio signal reaches the antenna via two or more distinct paths, typically caused by reflections, scattering, or diffraction from objects like buildings, terrain, or the ground. The receiver ends up getting several copies of the same signal, each traveling a different distance and arriving with its own delay, amplitude, and phase. When these copies combine, they can either reinforce or cancel each other, leading to fading or intersymbol interference if the system isn’t designed to handle it. That’s exactly what the option states: the signal arrives at the receiving antenna by two or more distinct paths. The other choices describe scenarios that don’t involve multiple separate propagation paths. A single path is the opposite of multipath; atmospheric degradation isn’t specifically about multiple paths; using multiple frequencies relates to diversity or bandwidth, not the arrival via distinct paths.