Analysis of C-V2X Antenna Performance on Vehicular Panoramic Glass

Abstract

This paper presents an analysis of a cellular vehicle-to-everything (C-V2X) quarter-wavelength monopole antenna performance when mounted on full glass roof. Antenna gain measurements performed on a full glass roof exhibited a performance degradation in a linear average gain (LAG) 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. Due to a lack of information about the electrical material properties and architecture of the full glass roof sample from the glass supplier for proprietary reasons, a series of gain measurements were performed for the C-V2X monopole when mounted on different glass material samples. The measurement findings suggested the existence of a metal layer in the glass roof sample. Based on this information, the antenna was simulated using a full-wave, three-dimensional electromagnetic field solver on the full glass sample with a low-emissivity (low-E) coating on the edges of the full glass roof. The simulation results showed acceptable agreement with the measurements. A practical solution is suggested to improve the C-V2X antenna performance on the full glass roof. Specific absorption ratio (SAR) analysis is conducted for the passengers in the front and rear seats due to the passenger radiation exposure from the C-V2X monopole antenna mounted on the glass roof. The SAR study showed that the effect of the roof-top C-V2X monopole antenna radiation on the passengers is negligible.