Beam Steering Circular Arrays in Elevation and Azimuth Planes for Automotive Radar Applications

Circular antenna arrays offer unique beam steering advantages over linear arrays which may be utilized in adaptive beam steered radar applications. Due to their inherent symmetry, circular arrays may be steered in the elevation plane as well as 360-degrees in azimuth. In this paper, two prototype passively phased circular arrays and corresponding feed systems are presented. The first array is designed for a narrow beam with small physical footprint to scan a conical broadside region. This array is a microstrip patch array designed at 10 GHz using HFSS and three prototypes are manufactured with distinct phase excitations to demonstrate the conical beam steering capability. The second array is designed at 2.45 GHz to scan a 360-degree azimuth region and is an 8-element circular array of CPW-fed dipole-like radiating elements. The microstrip array is fabricated and the experimental results show excellent correspondence to simulation. The second array is under fabrication.