Answer to Question #182668 in Electrical Engineering for dd123

Question

What are the near field and far field of an antenna? What are their major differences?

Answer 1

Answer to the question.

-Near field and far field of an antenna are regions of the electromagnetic field(EM) around an object such as a transmitting antenna.

-Major differences between near field and far field.

.In near field power is transmitted over short distance by magnetic field while in far field power is transferred by beams of electromagnetic radiation.

.If Fresnel number is larger than 1 the beam is said to be near field. If Fresnel number is less than 1 the beam is said to near field.

-Far field is sometimes referred to as electromagnetic radiation while near field is reffered to as EM.

-Thermal radiation in near field thermal wells, wires and dots deviates from planks law predictions while in far field field thermal wells, wires and dots significantly expands from planks law prediction.