Why L-Band ?

L-band corresponds to a wavelength of 24 cm, which, in contrast to the shorter wavelengths in C-band and X-band (wavelength 5.6 cm and 3.1 cm), is characterised by a large penetration depth for the volume scatterers, like vegetation, ice, dry soil and sand. Only by using long-wavelengths L-band is it possible to penetrate thick vegetation down to the ground and, therefore, measure its vertical structure. Another decisive advantage of using long wavelength radar signals is the greatly improved temporal coherence, important for the measurement of surface deformation and glacial motion. Thus Tandem-L will allow global motion measurements of the earth’s surface with cm down to mm accuracy over long periods.

 

Eindringtiefen-X-C-L
Comparison of the penetration depth in X-band, C-band and L-band with 3 cm, 5 cm and 24 cm wavelengths, respectively, for vegetation. While radar waves in X-band are only reflected by the top of the canopy, L-band penetrates to the ground. Only L-band radar systems can receive signals from all areas of the vegetation.

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