Research and literature studies within the area of remote sensing to map the outer and inner structures of buildings using SAR (Synthetic Aperture Radar) techniques show promising results. Capability to through wall sensing and rapid mapping of the inner structures of buildings is desirable, e.g. for police, fire brigades, rescue workers, military etc., to obtain an accurate and updated description of a building, its interior structure and surrounding urban environment, in a complex, acute situation. In this report, some results and conclusions from earlier performed electromagnetic (EM) simulations of buildings, with successively increasing complexity and realism, are presented. The EM simulations have been conducted within the FOI project "Bistatic SAR for urban environment". The earlier work has given important experiences, e.g. for selecting suitable parameters and geometries for remote mapping of the outer and inner structures of buildings using SAR. For SAR imaging of buildings with reinforced concrete walls, frequencies in the 0.3- 3 GHz regime should be used. A manual optimization of several parameters is so far needed to obtain good system performance. The performed studies shows remaining challenges in presenting calculated three dimensional (3D) SAR data in an efficient, intuitive way. The interpretation of such images likely can be enhanced by further development of existing methods for visualization. The merits of using more advanced SAR systems, providing 3D information, compared to more conventional SAR-system, providing 2D information, as well as the pros and cons of bistatic versus monostatic SAR system should be investigated in more detail. Further EM simulations should be performed for a realistic urban environment, with several closely located multi-storey buildings and be compared to with data acquired in SAR experiments.