Electromagnetic analysis of cascaded thick FSS for TM polarization has been carried out in this paper using MM-GSM technique. For the determination of generalized scattering matrix (GSM) of the FSS structure, only the co-polarized TM-TM field interaction is considered because the power coupled through the cross-polarized TM-TE interaction is negligibly small. It is observed that the cascaded FSS show dual-band behavior at 8.8 GHz and 11.66 GHz for TM wave at normal angle of incidence. Further, the transmission characteristics at higher incidence angles have also been investigated.