I. Introduction
To achieve the level of perception needed for future advanced driver assistance systems (ADAS) or autonomous driving, the sensor data is fused to combine the object detections from different sensors [1]. Hereby, radar sensors are employed, as they are able to provide accurate information on range, velocity, and the direction-of-arrival (DoA) of surrounding objects, even under harsh environmental conditions [2] –[4]. For short-range scenarios, for example automated parking systems, the usage of radar data can improve the detection capability significantly, as the widely used ultrasonic sensors face problems in harsh conditions as heavy rain [5]. Therefore, radar systems with good detection capabilities, even at very short ranges below 1 m, are needed.