Spectral characteristics of gaseous media and their effects on propagation of ultra-wideband radiation in the millimeter wavelengths

Some of the principal challenges in realizing modern wireless communication links at millimeter wavelengths are the effects emerging when the electromagnetic radiation propagates through the atmosphere due its complex refractivity. Propagation of the electromagnetic radiation is studied in the frequency domain, enabling consideration of broadband modulated signals. The theory is employed for the analysis of ultra-short pulse transmission in the millimeter wave regime. The atmospheric absorptive and dispersive effects on pulse propagation delay, width and distortion are demonstrated and discussed. Using second order expansion of the propagation factors leads to the derivation of approximated analytical expressions for the delay and width as a function of distance and carrier frequency. Conditions under which pulse compression or expansion occurs were identified. The effects, predicted by the analytical solution, were compared to the results obtained from a numerical simulation, aimed at the calculation of pulse evolution while propagating in the atmospheric media.