The penetration depth of the radar signal is related to the radar frequency
Higher frequency SAR primarily captures volume scattering near the top of the crop canopy. X-Band provides the best overall classification accuracy.
C-band and L-Band penetrate deeper and interact with other canopy components, and help to improve accuracies of higher biomass crops. Too great of penetration, especially with low biomass crops, results in interactions with the soil.
Multi-frequency SAR provides the best crop specific accuracies
Polarimetric scattering parameters appear to outperform multi-polarization data
Operational crop mapping and in-season crop acreage estimates could be supported by multi-temporal, multi-frequency and polarimetric SAR