08-01-2014, 03:10 PM
Measurement Study to Quantify The Attenuation Caused Due To Tree Canopies At 35 Ghz
ABSTRACT:
when the frequency is increased the attenuation is increased but there is a less attenuation window at 35 GHz. So if the devices having the working frequency near about 35 GHz is taken then communication will be effective.
The attenuation due to foliage is also very sensitive to the wavelength. Since the interaction between the tree and the electromagnetic field mainly is due to leaves and branches, the size and shape of these are important. When the wavelength is decreased, the losses increase due to a larger interaction between the incident field and the vegetation elements. This proceeds until the wavelength approach the same size as the scattering body and thus enters the resonance region. The attenuation of the leaves and branches increases with increasing frequency. When the wavelength is much less than the scattering body no resonance effects occur and the attenuation will be purely exponential.
At millimeter-wave frequencies, the dimensions of tree leaves, twigs, and tree branches are large as compared to the wavelength. The tree leaves and branches also usually contain water and hence result in absorption and scattering of electromagnetic waves as they propagate through vegetation. Foliage can not only introduce attenuation and broadening of the beam but also depolarization of the electromagnetic wave (Majeed and Tjuata, 1996).
ABSTRACT:
when the frequency is increased the attenuation is increased but there is a less attenuation window at 35 GHz. So if the devices having the working frequency near about 35 GHz is taken then communication will be effective.
The attenuation due to foliage is also very sensitive to the wavelength. Since the interaction between the tree and the electromagnetic field mainly is due to leaves and branches, the size and shape of these are important. When the wavelength is decreased, the losses increase due to a larger interaction between the incident field and the vegetation elements. This proceeds until the wavelength approach the same size as the scattering body and thus enters the resonance region. The attenuation of the leaves and branches increases with increasing frequency. When the wavelength is much less than the scattering body no resonance effects occur and the attenuation will be purely exponential.
At millimeter-wave frequencies, the dimensions of tree leaves, twigs, and tree branches are large as compared to the wavelength. The tree leaves and branches also usually contain water and hence result in absorption and scattering of electromagnetic waves as they propagate through vegetation. Foliage can not only introduce attenuation and broadening of the beam but also depolarization of the electromagnetic wave (Majeed and Tjuata, 1996).