The far zone is known as which term?

The far zone is known as which term?

• A. Far field
• B. Near field
• C. Fresnel zone
• D. Fraunhofer zone

Answer: (D)

In wave propagation and antenna theory, the far field is the region where radiation behaves like plane waves and the field pattern depends only on angle, not on distance. This is captured by the term Fraunhofer zone, the far-field region named after Fraunhofer. The boundary between near and far fields is typically around a distance of 2D^2/λ from the aperture (D is the largest dimension, λ is the wavelength). Inside the Fresnel or reactive near-field zones, the waves are more curved and the phase across the aperture matters, but once you’re in the Fraunhofer (far-field) zone, those complexities average out and the radiation pattern becomes essentially distance‑independent.

In wave propagation and antenna theory, the far field is the region where radiation behaves like plane waves and the field pattern depends only on angle, not on distance. This is captured by the term Fraunhofer zone, the far-field region named after Fraunhofer. The boundary between near and far fields is typically around a distance of 2D^2/λ from the aperture (D is the largest dimension, λ is the wavelength). Inside the Fresnel or reactive near-field zones, the waves are more curved and the phase across the aperture matters, but once you’re in the Fraunhofer (far-field) zone, those complexities average out and the radiation pattern becomes essentially distance‑independent.