# Forum

## Diffraction

9 posts by 6 authors in: Forums > CWNA - Enterprise Wi-Fi Admin
Last Post: July 21, 2006:
• Hi Everyone!

Is it true that Diffraction is less on higher frequencies?

Thanks

• AH,

Do you have a copy of the study guide?

-Lou

• Hi Lou.Cal,

I ve read the study guide (page 36-38), but it doesnt state any relationship between Diffraction and Frequency.
It just states that "At high frequencies, diffraction, like reflection, depends on the geometry of the obstructing object and the amplitude, phase, and polarization of the incident wave at the point of diffraction."

How about at low frequencies?

• "Is it true that Diffraction is less on higher frequencies?"

I guess that depends on what you mean by "less", as well as "higher"...

At frequencies in the Land Mobile Service (ie: 450 MHz), a signal will be less affected by diffraction than a signal at 2.4 GHz.

Think of a pager, which operates in the lower frequnencies. A pager signal has much better penetration through, under, over, and around an obstruction than a signal operating at 2.4 GHz.

But if you are asking if there is a big difference between, say, 2.4 GHz and 5.8 GHz, I would have to say no - none that would be noticeable. There would be a significnat difference in diffraction between frequenices in the MHz verses GHz bands, but once you get in the millimeter bands those differencies become less noticeable.

Hope that helps.

• Dennis,
You sound like a very good RF guy and we need more of those here in the forums. I also love your signature line. Perfect. :)

• Thank you Dennis for your answer.

• That's a great signature Dennis! :)

Devinator

• hi

diffraction leads to attenuation, at higher frequencies the wavelength becomes short so that the signal wavefront doesnt maintain its velocity when turning around the obstacles which causes the signal to degrade to a higher degree whereas at lower frequencies the wavelength is longer and the signal wavefront maintains its velocity to some degree so it soesnt get that much degraded...hope i m able to clear myself...

• Devinator Escribi?3:

That's a great signature Dennis! :)

Devinator

Not as theologically correct as yours, but one I have used for many years.

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