Power losses due to steering beam mis-alignment in directional-antenna millimeter-wave systems

Path loss characteristics are usually studied in terms of distance and/or frequency under omni-directional antenna assumptions. When directional antennas are employed, an additional power loss may arise due to the beam mis-alignment between TX and RX beam axes. This paper investigates this additional power loss behavior based on field measurement data. The measurements were conducted in downtown Seoul in the frequency band of 28 and 38 GHz. Both LOS and NLOS measurements show similar results in the average power loss. This suggests that a slight angle deviation results in a significant power loss.