Antenna Materials Development in Automotive Radars

Automotive radar sensors are used for various functions, such as blind spot detection (BSD), lane change assistance (LCA), collision mitigation (CM), parking aid (PA), and rear cross traffic alert (RCTA). And the different types of radars are mounted around a car depending on the required functions. Antenna design and materials can be optimized according to the radar types. Recently thermoset materials have started to be used for Print Circuit Board (PCB) antenna for mm Wave applications due to the benefit of simple PCB process, design flexibility and lower cost compared to PTFE. However, the usage of thermoset materials has been limited for car radar antennas because they are generally thermally unstable and have higher loss. By selection of right thermosetting resin system and optimizing resin formulations, we have developed thermoset materials which demonstrate stable Dk/Df after aging at 125C. We confirmed the electric stability at 77GHz using the ring resonator method which considers the effects of dielectric layer, copper foils and the interface between them. The insertion loss of the materials that we have developed is comparable to PTFE materials being used for automotive radar applications.