Reflectarray development for improving NLOS radio channel

In urban areas where there are many high buildings, the radio wave from base stations of cellular mobile communications may be blocked by these buildings, particularly in narrow streets right under these buildings. In order to improve the radio channel in these blocked areas, we have carried out researches to develop reflectarray as a passive reflector mounted on the wall of these buildings to scatter the incident wave from the base station antennas to these areas. This report gives a brief review of our previous researches on reflectarray development for improving wireless propagation channel, including development of reflectarray with band-pass filter, dual-band reflectarray, and so on. An outdoor measurement is demonstrated to show the effectiveness of the reflectarray approach in improving the NLOS radio channel in urban areas.