Design of a Compact Multi-Band (Cellular 5g/GNSS/V2x) Antenna and Rigorous Analysis of Antenna Performance on Glass Roofs for Vehicular Platforms

The growing market competition between the automakers led to the implementation of more entertainment systems and extra features to satisfy the automotive customers. The entertainment systems depend on wireless services and communication which led to increasing numbers of antennas mounted on and inside the vehicles. This dissertation is focused on automotive antenna design and the effect of the vehicle environment on the antenna performance. For the first part of the dissertation, a compact multi-band monopole antenna is designed for vehicular roof top shark-fin applications. The proposed multi-band antenna covers 5G sub-6GHz, GNSS and V2X frequency bands starting at 617MHz to 5925MHz. The presented antenna is a three-dimensional monopole antenna with two branches to cover the required bands with compact size to fit inside a roof top shark-fin. The antenna is simulated, optimized and then a prototype is fabricated, and its radiation characteristics are measured when mounted on one-meter ground plane and on a vehicle's roof. For the second part of the dissertation, the analysis of a C-V2X quarter-wavelength monopole antenna performance when mounted on a vehicle's glass roof is presented. Antenna gain measurements performed on a full glass roof exhibited a performance degradation in a linear average gain of 8 dB compared to when the same antenna is mounted on a metallic ground plane. In addition, the antenna radiation pattern on the glass roof had deep nulls. The antenna was simulated using a full-wave, three-dimensional electromagnetic field solver on the full glass sample with low emissivity (low-E) coating on the edges of the full glass roof and the simulation results showed acceptable agreement with the measurements. Simulation shows that the C-V2X antenna performance on the full glass roof can be improved by moving the low-E coating from underneath the glass to top of the glass