The ITU Vegetation Model is a radio propagation model

Radio propagation model

A radio propagation model, also known as the Radio Wave Propagation Model or the Radio Frequency Propagation Model, is an empirical mathematical formulation for the characterization of radio wave propagation as a function of frequency, distance and other conditions...

 that estimates the path loss

Path loss

Path loss is the reduction in power density of an electromagnetic wave as it propagates through space. Path loss is a major component in the analysis and design of the link budget of a telecommunication system....

 encountered due to the presence of one or more trees inside a point to point telecommunication

Telecommunication

Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...

 link. The predictions found from this model is congruent to those found from Weissberger’s Modified Exponential Decay Model

Weissberger's Model

Weissberger’s modified exponential decay model, or simply, Weissberger’s model, is a radio wave propagation model that estimates the path loss due to the presence of one or more trees in a point-to-point telecommunication link...

 in low frequencies.

Applicable to/under conditions

• This model is applicable on the situations where the telecommunication
  Telecommunication
  Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...
  
   link has some obstructions made by trees along its way

• This model is suitable for point-to-point microwave
  Microwave
  Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...
  
   links that has a vegetation in their path.

• Typical application of this model is to predict the path loss
  Path loss
  Path loss is the reduction in power density of an electromagnetic wave as it propagates through space. Path loss is a major component in the analysis and design of the link budget of a telecommunication system....
  
   for microwave links.

Mathematical formulation

The model is formulated as:



Where

L = The path loss. Unit: decibel

Decibel

The decibel is a logarithmic unit that indicates the ratio of a physical quantity relative to a specified or implied reference level. A ratio in decibels is ten times the logarithm to base 10 of the ratio of two power quantities...

 (dB)

f = The frequency of transmission. Unit: megahertz (MHz)

d = The depth of foliage along the link: Unit: meter (m)

Points to note

This equation is scaled for frequency specified in megahertz (MHz).

The depth of foliage must be in the units of meters.