The Global Status Report on Road released by WHO suggests that a staggering 1.35 million road accidents happen worldwide annually. This has forced the governments worldwide to adopt legislation that make it mandatory to have a few ADAS applications in automobiles in order to improve road safety. An analysis of the automotive market suggests a higher demand for vehicles with 4- and 5-star ratings in Euro-NCAP safety testing. Towards realizing such lofty ideals, the vehicles have a number of different types of sensors deployed for achieving higher safety, situational awareness and vehicle to everything communication (V2X). Automotive Safety Engineers have of late placed excessive demand on vehicular RADARs, which requires an RF front-end like the communication systems on-board to also double as a situational awareness sensor. This has caused the number of antennas onboard the automobile to increase, adding to its kerb weight. In addition, a conflict among the sensors employed for various such ADAS applications in terms of vantage locations that maximize functionality has also been an adverse outcome. The task we report here had aimed for an antenna aperture tuning scheme suitable for long and medium range RADAR sensors, that are employed in various ADAS applications, which would result in a deployable solution with an optimum balance in size, weight, power and cost.
With the ever-increasing number and types of sensors on board autonomous vehicles, their judicious selection and placement has a crucial role to play in the form and functionality of the underlying ADAS applications. RF ADAS applications demands radio front-end aperture sharing and farmed-out locations without compromising on the resolution and imaging capabilities. Antenna arrays with better spatial resolution and imaging capabilities are employed for ADAS applications using RADAR sensors. In this context, an attempt has been made to investigate antenna super-arrays optimized for multiplexed ADAS applications. The sparse superarray is devised by replicating a hexagonal subarray design with 8 isotropic antenna elements. The subarray has a unique novelty attribute in that, they can be individually rotated about the vehicle's longitude axis in order to harness the asymmetry in the antenna beam cross-section defined for a specific ADAS application. Three different replication schemas have been tested, the best out of them has been scaled up for achieving ADAS-optimized replication topologies. Such shared apertures are then mounted on a common platform and shared among the select ADAS applications, viz. pothole detection, cruise control, and pedestrian detection, to showcase their tandem functionality.