I would like to simulate UWB Synthetic Aperture Radar for foliage penetration for military vehicles and I want to choose the suitable radar frequency for that application and the bandwidth. thanks in advance for your help.
VHF, and perhaps UHF depending on foliage. It is a complicated topic. May I suggest beginning with a read of the book "Foliage Penetration Radar: Detection and Characterisation of Objects Under Trees (Electromagnetics and Radar)" by Mark Davis.
Happ, L., Kappra, K. A., Ressler, M. A., Sichina, J. P., Sturgess, K., & Le, F. (1996, May). Low-frequency ultra-wideband synthetic aperture radar 1995 BoomSAR tests. In Radar Conference, 1996., Proceedings of the 1996 IEEE National (pp. 54-59). IEEE.
The choice of frequency will also depend upon the available aperture time. Therefore, for Comparable attenuations, higher frequency will mean smaller aperture time for a required resolutio.