The coverage sectorization via the utilization of directional antennas potentially increases system capacity of mobile communication. The vertically narrow but horizontally broad beam widths of antennas have caused very wide inter-sector coverage overlapping and subsequent poor quality of communication such as inappropriate power controls of handsets, irregular inter-sector handover, and undesired inter-cell and inter-sector interferences. A technique based on the utilization of resistive plates to optimize the area of overlapping coverage is thus studied. The undesired electromagnetic (EM) field in the overlapping regions is guided to the main beam of each sector via the EM reflection from the surfaces of the plates. The advantages of the resistive plates are that the edge diffraction, as well as the multipath effects caused by the edges, can be minimized by increasing the resistance on the edges of the surfaces to an extremely large value.