A theoretical examination of the properties of the exchange bias phenomenon for sandwich FM/AFM/FM structures, which are actively studied in experiments. Magnetization dependences on the external magnetic field are obtained under the proposed discrete model of ferromagnetic layers of such multilayer structures. It is shown that the magnetization field dependences have a horizontal plateau, a splitting of the hysteresis loop, and asymmetry. We examine the influence of the interface defects on the exchange bias phenomenon and its features. The results are qualitatively consistent with experimental data.