Vegetation Loss at D-Band Frequencies and New Vegetation-Dependent Exponential Decay Model

With the potential of fixed wireless access (FWA) networks as an alternative to optical fiber, it is necessary to determine vegetation loss at millimeter wave frequencies. In this article, we present vegetation loss measurement results for different types of vegetation, including trees, hedges, and forests, at frequencies ranging from 110 to 170 GHz. An experimental method is proposed to determine the average loss per meter vegetation depth (VD) for different vegetation types. Average losses at 140 GHz range from 0.2 dB/m for an open forest, and up to 9.8 dB/m for dense hedges. As there is a large variance of vegetation loss for different vegetation types, we propose a novel vegetation-dependent exponential decay (VED) model, expressing vegetation loss as a function of VD, frequency, and vegetation density, which is expressed by the plant area index (PAI) parameter. The VED vegetation loss model can be used for network design, and to perform accurate link budget calculations.