Microwave Propagation Through Sand and Dust Storms (Haboobs)

• Main Author: Ahmed, I. Y.
• Published: University of Newcastle upon Tyne 1976
• Subjects: 621.381
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.447064

The thesis investigates the effects of sand and dust storms on the propagation of microwave radiation. To investigate this the dielectric properties of the basic constituents of these storms, at microwave frequencies, for concentrations varying between 1.3 to 10-6 gm. cm-3 in air, have been determined. The microwave bridge and a phase shifter technique have been used for high (or bulk) concentration studies of sand and dust (1.3 <P <1.9 gm. cm3). A special technique using an open cavity resonator (having high Q-factor) has been used for studies at very low (or powder) concentrations (10 6< P< 10-2 gm.cm3) typically found in storms. The. values of the refractive indices and loss tangents obtained from the open cavity resonator measurements were then compared with those extrapolated from the simpler bulk measurements results and the various well-documented equations (relating permittivities of dispersed particles). The Bottcher and the Bruggeman equations are examples of these extrapolation formulae. In conclusion the open cavity resonator results were preferred. Using the actual experimental results the possible effects of these storms (e. g. attenuation and refraction) on the performance of-communication systems are also discussed.