Antenna field concept

[adeel.sid]

Hello
i want to ask that;
"what is the difference b/w antenna near field and antenna far field?"
Please explain in detail
also upload any document (.pdf or other) related to it.
Thanks in Advance

 

[vicky]

HI Dear,

the near and far field is related to the electromagnetic field fo antenna .

near field related to the field nearest to the antenna beyond the near there is far field or infinite field.


The term near-field region (also known as the near field or near zone) has the following meanings with respect to different telecommunications technologies:

The close-in region of an antenna where the angular field distribution is dependent upon the distance from the antenna.
In the study of diffraction and antenna design, the near field is that part of the radiated field that is within a small number of wavelengths of the diffracting edge or antenna.
In optical fiber communications, the region close to a source or aperture.
The diffraction pattern in the near field typically differs significantly from that observed at infinity and varies with distance from the source.




The far-field region is the region outside the near-field region, where the angular field distribution is essentially independent of distance from the source. If the source has a maximum overall dimension D that is large compared to the wavelength, the far-field region is commonly taken to exist at distances greater than D²/λ from the source, λ being the wavelength.

For a beam focused at infinity, the far-field region is sometimes referred to as the Fraunhofer region. Other synonyms are far field, far zone, and radiation field

 

[Alex0131]

These terms are briefly explained in the excerpt "antenna near field" . By the way, somebody knows, whence this excerpt?

 

[adeel.sid]

Thank all of you for support
There is still something I want to ask that:
I heard that;
near field isn't deterministic(Field can be predicted) while
while far field is!"
Is it True?

 

[sundarmeenakshi]

Thank all of you for support
There is still something I want to ask that:
I heard that;
near field isn't deterministic(Field can be predicted) while
while far field is!"
Is it True?

no it is exactly opposite

 

[cesare]

You can take a look at SWRA046A from TI (www.ti.com)