sentences:  The clutter in the main beam is extended over a range of grazing angles and the backscatter coefficient depends upon grazing angle.Clutter will appear in the antenna sidelobes, which again will involve a range of grazing angles and may even involve clutter of a different nature.The calculation is similar to the previous examples, in this case the illuminated area is
  
  which for small beamwidths simplifies to
  
  The clutter return is as before
  
  Substituting for the illuminated area formula_28
  
  This can be simplified to