A flat-panel repeater includes a housing having a pair of oppositely facing surfaces, at least one antenna element mounted to each of the surfaces for radiating energy in a direction opposite to that of an antenna element mounted to the other of the surfaces, and an electronic circuit mounted within the housing and operatively coupling signals between at least one antenna element on each of the oppositely facing surfaces of the module. Isolation between the antennas on opposite sides of the repeater is improved by various techniques, such as use of adaptive cancellation which removes a significant portion of the feedback signal power, therefore increasing the total system isolation by the same amount. This additional isolation can be used to achieve greater system gain, and therefore significantly extend the range of the system. The repeater may also include a beamforming arrangement for creating a desired antenna pattern of one antenna relative to a base station and a desired antenna pattern of the other antenna relative to subscriber equipment.