In automobiles, many electronic devices are usually designed to increase safety or enhance the driving experience, and most of them depend on wireless communication to perform their task to the roadside environment. Antennas on a vehicle form the basis of navigation, telemetry, and all kinds of onboard communication. Systems such as Bluetooth, satellite navigation, radio, vehicle tracking, collision notification, and remote diagnostics all depend on high-performance antennas that perform as intended in challenging environments. The demand for antennas in wireless communication system for automotive applications is growing rapidly. These antennas are used in collision avoidance system (CAS), pre-crash safety systems, Vehicle-to-vehicle communications, Global Positioning Systems (GPS), Wireless Local Area Network (WLAN), tyre pressure monitoring system (TPMS) etc. For better effectiveness in these new applications, a small, multi-band, multi-functional antenna is required instead of conventional single band antennas like whip antenna. Printed antenna system mounted in an aperture in the roof of a car is used for broadcast signal reception from 88-108 MHz.
The structure of antenna should be as compact as possible for easy integration into the vehicle and it must be suitable for mass production to minmize the average cost per unit. An automotive system, performance-wise, is required to maintain a low sidelobe level, so that misdetections could be avoided. All these facets pose challenges to the antenna design for automotive radars.