The electric and magnetic fields in the immediate vicinity of an antenna are called what?

• A. Near Fields
• B. Far Fields
• C. Transitional Fields
• D. Radiative Fields

Answer: (A)

In the area just around an antenna, the fields behave as the near-field. Here the electric and magnetic fields don’t form a spreading traveling wave yet; energy is largely stored in the fields rather than radiated away. This reactive region features fields that can be out of phase and bound to the antenna, with energy sloshing between electric and magnetic forms. Only farther away do the fields become propagating radiation, forming the far-field where E and H are perpendicular and in phase. There is a transitional radiating near-field region between these, but the immediate vicinity is best described as the near-field.