Vegetation Attenuation for Several Evergreen Shrubs at 31 and 5 GHz

Abstract

Millimeter wave (mmWave) cell sizes are meant to be small, and hence base station heights will often be low. This will increase the probability of a link traversing vegetation. For such cases, it is important to know the range of expected attenuations. In this paper, radio wave attenuation and depolarization effects through several broadleaf evergreen shrubs are reported, based upon measurements at two frequencies, 5 and 31 GHz. From this, we analyze the relationship between this attenuation and the two frequencies, and the shrub density, depth, and measurement geometry. Three different shrub species with different densities and depths, and for different measurement geometries, were employed. Specific attenuations at 31 GHz can exceed 20 dB/m for the densest shrubs. These results will be useful for link budget design, and outdoor and outdoor-indoor models for future mmWave communication.