Why higher frequencies has higher pathloss ?

[islam wagih]

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]

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]

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]

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]

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) ....
FIGURE5.jpg
brs

[proy1_10]

http://en.wikipedia.org/wiki/Free-space_path_loss

Read "Physical explanation"