Compensation of vehicle-specific antenna radome effects at 5.9 GHz

Future vehicles are expected to integrate multiple radio access technologies to offer traffic information services for Intelligent Transportation Systems (ITS). Dedicated short range communication (DSRC) being designed exclusively for vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication is one of the major candidates to enable such services. The focus of this paper is to shed light on the integration aspects of this technology, especially in regards to the antenna design. A methodology is presented to overcome the difficulties occurring from the integration of the antenna in the radome on the vehicle rooftop. With help of simulations and measurements it is illustrated how the conventionally unwanted dielectric lens effect of the antenna radome resulting in nulls in the radiation pattern can be used to deliberately increase the antenna performance. The performance enhancement by using the antenna radome as a dielectric lens is validated with four prototypes in a semi-anechoic chamber. It is moreover shown that simplified geometrical shapes such as cuboids can be used to describe efficiently the behavior of geometrical more complex radome designs. The greatest advantage of our proposed methodology to enhance antenna performance is that it can be employed without changes of any electronic control units. Thus it can easily be included in a running production cycle without even altering any design elements of the vehicle. To demonstrate to which degree the achieved enhancement on component level translates into system level we also present simulation results of a test scenario including a vehicle and a road-side unit. The outcome of the system level simulations shows substantial improvements in the received signal strength (RSS).