View Full Version : Why higher frequencies has higher pathloss ?
islam wagih
2013-09-17, 06:41 PM
Dears,
If any one could support me with detailed answer about Why - physically- higher frequencies has higher pathloss ?
Also if any one could provide me with any book about Radio engineering I will be very grateful.
Thanks
auto_art
2013-09-17, 07:02 PM
the answer lies with friss equation.
if you remember the path loss between two isotropic antennas in free space: Path loss in dB
L= 20 log10 (4.pie.d/lambda)
l is loss, lambda is wavelength, d is distance
wavelength we know inversely prop. to freq. hence more frequency more loss.
islam wagih
2013-09-17, 08:02 PM
Thank you for your reply but I want to understand the physical reasons for that :)
the answer lies with friss equation.
if you remember the path loss between two isotropic antennas in free space: Path loss in dB
L= 20 log10 (4.pie.d/lambda)
l is loss, lambda is wavelength, d is distance
wavelength we know inversely prop. to freq. hence more frequency more loss.
wernfried
2013-09-17, 10:10 PM
Hi
Actually the pathloos depends not on the frequency. The reason to have the frequency in pathloss equation is due to effective antenna area which depends on frequency.
Have a look at Wikipedia to find more details: https://en.wikipedia.org/wiki/Free-space_path_loss
Kind Regards
aubidamax
2013-09-18, 12:30 AM
when frequency increase the value of Lamda (length of signal wave) decease which mean the signal at same power have to propagate (move) less distance (increased pathloss) ....
33674
brs
proy1_10
2013-09-18, 05:07 PM
http://en.wikipedia.org/wiki/Free-space_path_loss
Read "Physical explanation"
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