Effects of antenna directivity on indoor multipath propagation characteristics at 60 GHz

In millimeter-wave indoor communications systems, the radiation patterns of the antennas at base stations and remote terminals have a significant influence on the channel characteristics. The work reported in this paper investigated the effects of the radiation patterns of the antennas at remote terminals on multipath propagation characteristics. These effects were investigated by indoor propagation measurements at 60 GHz conducted in a modern office room and by ray-tracing simulations based on geometrical optics. Multipath channel characteristics are compared in terms of impulse responses and their RMS delay spreads for an omnidirectional antenna and for three directive antennas with different beam widths. From the results of the measurements and ray-tracing simulations, the use of a directive antenna at the remote terminal is demonstrated to be an effective method of reducing the effects of multipath propagation