MMW propagation in warm water evaporation ducts

Abstract

This paper focuses on Ka-band (35 GHz) propagation in maritime evaporation ducts using M-profiles derived from high resolution radiosonde observations from locations with warm sea surface temperature (> 25°C) and large M-deficits (ΔM > 60 M-units), and the equivalent ln-linear model fits to the radiosonde M-profiles. The measured radiosonde M-profiles have evaporation ducts that are more closely approximated by a bi-linear model rather than the typical ln-linear model. Using a parabolic wave equation propagation model, the resulting differences in ducted path loss coverage diagrams will be examined and related to the curvature properties of the M-profile near the duct height. The poor fit of the ln-linear model to measured M-profiles results in substantial differences in the RF propagation.