Atmospheric effects in ultra wideband wirless comunications in the Extremely High Frequency (EHF)

The growing demand for broadband wireless communication links and the lack of wide frequency bands within the conventional spectrum causes us to seek bandwidth in the higher microwave and millimeterwave spectrum at Extremely High Frequencies (EHF) above 30GHz. One of the principal challenges in realizing modern wireless communication links in the EHF band is phenomenon occurring during electromagnetic wave propagation through the atmosphere. Space-frequency theory of the propagation of an ultra-wide band radiation in dielectric media is presented. Characterization of the atmospheric medium is via its refractivity leading to a transfer function, which describes the response of the medium in the frequency domain. This description enables the consideration of broadband signals taking into account inhomogeneous absorptive and dispersive effects of the medium. Analytical expressions are derived when a pulse-modulated signal is propagating in a general dielectric material. We demonstrate the approach by studying propagation of ultra-wide band signals, while transmitted in the vicinity of the 60GHz absorption peak of the atmospheric medium at millimeter wavelengths.