Diffraction of electromagnetic waves from planar structures composed of perfect electromagnetic conductor (PEMC) material has been studied, by applying the duality transformations as proposed by Lindell and Sihvola. The characteristics of these PEMC planar structures (step, slot and plate) in terms of co- and cross-polarized diffracted fields have been analyzed. Effects of the PEMC structures have been studied in free space as well as in four different soil models. Perfect electric conductor (PEC) and perfect magnetic conductor (PMC) media are sub-cases of PEMC. Further, we has studied that PEC and PMC are the special cases of PEMC, it means there exists no cross-polarized field.