What is Antenna far field distance ?

In the context of antennas, the far-field distance (also known as the far-field region or Fraunhofer region) is the distance from the antenna at which the electromagnetic radiation pattern becomes essentially stable, and the behavior of the radiated waves can be approximated as a spherical wavefront, a plane wave or a well-defined beam. It is a region in which the electromagnetic fields produced by the antenna exhibit certain predictable characteristics. Let us explore far field distance calculator and understand far field formula and its applications.

The far-field distance from an antenna depends on various factors, including the antenna's size, operating frequency, and radiation pattern. It can be calculated using formulas that take into account these parameters. Understanding the far-field region is crucial in antenna design and deployment because it helps engineers determine the coverage area, gain, and radiation pattern of an antenna at a specific distance, which is essential for effective communication and signal reception.

Far field distance calculator

Following calculator takes input as largest of diameter of the antennas from Equipment Under Test antenna and test antenna and operating frequency and provide far field range as output.


Antenna diameter (meters) (input1) :

Operating Frequency in MHz (input3) :


Far Field Range (Output):

EXAMPLE of far field distance calculation :
INPUTS : d = 2.4 meters, Frequency = 6000 MHz
OUTPUT: Far Field distance >= 230.4 meters

Far Field Formula

Following are the antenna range types:
• reactive near field ( up to λ)
• reactive radiating near field ( up to 3*λ)
• radiating (fresnel) near field (up to 2*D2 /λ)
• radiating far field ( >=2*D2 /λ)

The far field distance can be calculated based on antenna diameter ('D') and operating frequency ('f'). It can be expressed as using following formula or equation.

far field range formula

Conclusion : The far field formula and its associated far field distance calculator serve as invaluable tools in various fields of science and engineering, particularly in the realms of optics, electromagnetic wave (EM) propagation and antenna design.

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