A transport theory of millimeter wave propagation in woods and forests

TLDR

The study presents a theory of millimeter‑wave propagation in woods and forests that models vegetation as a statistically homogeneous random medium of scatterers with a narrow forward lobe and omnidirectional background. Using scalar transport theory, the authors characterize the medium with four theoretical parameters and compute coherent and incoherent field intensities for a vegetation half‑space illuminated by a plane wave. The resulting formulas and graphs describe the range dependence of coherent and incoherent intensities and the beam‑broadening of the incoherent component, and they agree qualitatively with independent experimental measurements. Keywords: millimeter‑wave propagation, RF propagation in woods/forests, terrain effects, transport theory, random media, coherent and incoherent field components, range dependence, beam broadening.

Abstract

Abstract : A theory of mm wave propagation in woods and forests is presented which models the vegetation environment as a statistically homogeneous random medium of scatterers characterized by a scatter function (phase function) with a narrow forward lobe and an omnidirectional background. The model describes the medium in terms of four overall theoretical parameters whose numerical values can be determined in principle by comparison of analytical results and experimental data. The scalar transport theory is used to determine the coherent and incoherent field intensities in the forest medium; the problem solved is that of a vegetation halfspace illuminated by a plane wave. Formulas and graphs are presented on the range dependence of the coherent and incoherent intensities, and on the angular spectrum (beam broadening) of the incoherent intensity. Comparison with experimental results obtained by an independent investigation has shown good qualitative agreement of calculated and measured results. Originator-supplied keywords include: Millimeter wave propagation, RF propagation in woods/forests, terrain effects on millimeter wave transmission, Transport theory, Random media, Coherent and incoherent field components, and Range dependence and beambroadening of millimeter waves in vegetation.