Investigation of Millimeter Wave’s Cross Polarisation Differentiation in Dust and Sand Storms
Keywords: millimeter wave, cross-polarization discrimination, DUSA storms, signal propagation, differential phase rotation, differential attenuation, complex scattering
The performance of electromagnetic wave links in dust and sand (DUSA) storms has become a topic of interest to researchers, especially with emphasis on the attenuation of signal. But the phase rotation and the cross-polarization components are not yet sufficiently treated. This work investigates the cross-polarization differentiation (also known as discrimination) as a result of DUSA storms at high frequency such as the millimeter wave band. The paper proposes mathematical models of propagation of waves in DUSA storms using the forward scattering amplitude of DUSA particles and the Rayleigh technique. The suitability of the Rayleigh approximation for the models are validated by setting three different conditions. The results show fidelity of the technique for evaluating scattering of ellipsoidal DUSA particles for the range of sizes and frequencies considered. The coefficients of the scattering are thus determined and models for attenuation and phase rotation are introduced in terms of visibility. The results obtained from the models show close agreement with some earlier published results when compared. We then computed both the attenuation and the phase rotation differentials and the cross-polarization discriminations are then predicted using the parameters from the models as inputs. The attenuation during dry DUSA storms becomes significant only when the visibility is low and severe. At such visibility, the cross-polarization discriminations also become low (i.e. significant) and the same trend and pattern is observed when the frequency is increased.