MILLIMETER WAVE PROPAGATION IMPAIRMENTS, MODELS, AND ON-GROUND EXPERIMENTATION

The V and W-bands are becoming of interest to satellite designers due to the large availability of bandwidth and the potential multi-gigabit data rates. Implementation of a satellite communication channel at these frequencies has not been documented in literature, and commercial wireless services at these frequency bands are undeveloped. Furthermore, millimeter waves are affected much more by atmospheric attenuation, with rain being the most detrimental and uncertain. Predictive models of rain attenuation claim some degree of accuracy up to 55 GHz, although they are primarily based on measurements at 40 GHz and below. It is imperative that a high-frequency channel be fully characterized utilizing data at or near the W/V operational frequency. Historically, characterization and model validation has been accomplished via the use of a space-beacon and a distributed network of ground terminals. Although this method is very useful, it is extremely expensive to implement. The eventual application of the research documented in this thesis is the development of a wideband, global satellite communications architecture. Prior to realizing such architecture, propagation effects need to be statistically characterized to ensure a high degree of confidence. Recommendations from the ITU-R of both clear-sky and atmospheric attenuation contributions were taken to create a baseline link-budget model, which is developed in this thesis. An experimental setup, execution, and analysis are presented, which was used to assess the link-budget model’s accuracy during rain. The power loss across a channel was measured during simulated rainy conditions for the frequency range of 10-40 GHz. The experiment was conducted via the use of a rain simulator, which simulates a uniform 60 mm/hour monsoon. A uniform rainfall distribution is ideal for testing model accuracy for rain losses. Prior to accounting for multipath, the model achieved errors of only 8.69%, -4.13%, 3.51%, and 5.52% for 10, 20, 30, and 40 GHz propagation respectively. These results support the developed model, but more data is required to better verify and validate the model. The results presented in this research thesis will serve as a baseline model for further investigations at smaller wavelengths.Air Force Research Laboratory (AFRL)Electrical EngineeringMastersUniversity of New Mexico. Dept. of Electrical and Computer EngineeringChristodoulou, ChristosLane, StevenSchamiloglu, Ed