The near zone length is also called the Fresnel zone.

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

Answer: (A)

In propagation around an antenna, the space close to the radiator where the wavefronts are curved and the phase varies across the aperture is the near field. This region is commonly described by Fresnel diffraction concepts, so its length is referred to as the Fresnel zone. The key idea is that, within this zone, the wavefronts aren’t yet essentially planar, and the field cannot be treated as simply a plane wave. Beyond a certain distance, the wavefronts become nearly planar, marking the far-field region (the Fraunhofer zone). So the near zone length being called the Fresnel zone reflects that close-in region where Fresnel-type, non-planar-phase behavior dominates.