I am considering doing a PhD on L-Band Polinsar . There is quite a bit of groundwork now in this field with the repeat pass systems from DLR E-SAR and ALOS-PALSAR. I have worked with data from both of these sensors in the past and doing a PhD will be natural continuation.
On the other hand there are disadvantages of doing a PhD too early in the career without an explicit academic bent, or even worse a PhD constrained by commercial interests( not that anything in life is ever unencumbered by it). If anyone wants to offer me any free advice to help me make up my mind feel free to do so.