Hi Sateesh
You can download the kernel 720 from service market place database depend and indent kernel release's.
1. Rename those files from SAPEXE_<patch_level>.CAR to SAPEXE.CAR & SAPEXEDB_<patch_level>.CAR to SAPDB.car.
2. Those two files you can copy to your kernel media
Could you share you portal support package level?
BR
SS