Abstract: Formula of equivalent edge currents for calculating physical optical (PO) field (POEEC) of planar objects given by Antio et al. is extended to calculate PO field of polyhedral structures. In addition, the extended POEEC is modified to reduce the singularity down to only one. The summation of the new POEEC and the less singularity PTDEEC derived by Michaeli gives the GTDEEC which can be used to calculate the total field of polyhedral structures. Bistatic RCS of a cube and finite cylinder are calculated using GTDEEC presented in the paper. The calculated results are in good agreement with those from measured and the other methods. This fact confirms the validity of the formula based on GTDEEC.