Vehicle-to-Everything (V2X) communication was born as a worldwide service, within the framework of Intelligent Transportation Systems (ITS) in the 5.9 GHz spectrum, to reduce fatal accidents and keep the traffic flowing in time-varying environments. The reasonably high frequency of operation with regard to most other automotive applications offers short range communications (up to 1 km) with a high data rate, low weather-dependence, and global compatibility and interoperability. However, the increasing trend to miniaturize and hide the antennas to preserve the aesthetics of the automobile has a negative impact on the antenna performance. This framework represents a great challenge from the antenna engineering perspective, and it opens the door to numerous investigations on new antenna concepts and placements to cope with the demanding requirements inherent in a safety system. Omnidirectional radiation patterns are required to be able to receive and send any kind of alert in any direction of space in the horizontal plane in which car traffic runs. The circularity of the far-field patterns in the horizontal plane is notably affected by the proximity of the V2X antenna to other neighboring antennas and by the actual location of the antenna in the automobile. This dissertation investigates the several electromagnetic propagation effects in the 5.9 GHz ITS spectrum affecting the performance of the antennas when considering the vehicle body and the different materials of the car in close proximity to the antennas. The dissertation also investigates different solutions for various antenna placements. From shark-fin antennas on the roof of the car through various mounting positions to implement decentralized macro-diversity antenna systems, to completely hidden micro-diversity antenna systems underneath the roof of the car. The performance of the different antenna solutions is analyzed by means of statistics and exploratory data analysis (EDA) to characterize the stochastic behavior of the radiation patterns at 5.9 GHz under the influence of the vehicle. Full-wave, asymptotic and hybrid simulation techniques are performed depending on the nature of the electromagnetic issue and the results are corroborated by measurements done in an anechoic chamber when dealing with stand-alone antennas or in an Open Area Test Site (OATS) when measuring with the vehicle. Statistical tests are computed to analyze the agreement between measurements and simulations.     «

Vehicle-to-Everything (V2X) communication was born as a worldwide service, within the framework of Intelligent Transportation Systems (ITS) in the 5.9 GHz spectrum, to reduce fatal accidents and keep the traffic flowing in time-varying environments. The reasonably high frequency of operation with regard to most other automotive applications offers short range communications (up to 1 km) with a high data rate, low weather-dependence, and global compatibility and interoperability. However, the inc...     »