Reducing the Radar Cross Section of Microstrip Arrays Using AMC Structures for the Vehicle Integration of Automotive Radars

Automotive radar sensors for driver assistance systems are usually installed behind the bumper of the car. Multiple reflections between radar and bumper can occur and may lead to a wrong estimation of the direction of arrival of the signal reflected by the target. This paper presents an effective solution to improve the hidden integration of radars in a vehicle. In particular, this paper proposes the design of a low-radar cross section (RCS) millimeter-wave antenna array to reduce the reflections toward the car fascia. The design exploits the properties of artificial magnetic conductors (AMCs) to cancel out the wave backscattered by the antenna array. The integration of the AMC with the antenna array is analyzed in detail. The experimental results prove that the array with low RCS can mitigate the multiple reflections. Moreover, the measurement results show that the proposed antenna has 20 dB RCS reduction at 76 GHz.