Design of antenna arrays for car radar

Abstract

In recent years, the development and promotion of 'driverless' vehicle have become main trend in the future of vehicles. Automotive radars are equipped in most vehicles for safety enhancement and driving assistant. As the essential component of the automotive radar, antenna dominated performance, size and cost of the radar system. Thus, the development of car radar antenna is a popular research for engineers. This paper is presenting a 77 GHz microstrip patch antenna array that can be applied for automotive radar prototype. The antenna array consists of 8 rows of 1x8 sub-array, a 1-to-8 unequal power divider and a microstrip fed line. First a 1x8 sub-array is designed with width tapering to control current distribution and side lobe suppression. In order to reduce side lobe level (SLL), a 15 dB Dolph-Chebyshev weights distribution is implemented for width tapering. Based on the 1x8 sub-array, a 8x8 array is constructed to achieve better gain performance. The design and simulation of the antenna array are performed in ANSYS HFSS software. The dimension of the 8x8 antenna array is 30 mm x 26 mm. Rogers 3003 is implemented as the dielectric substrate in between ground plane and conducting patch. By HFSS simulation, the S-parameter and radiation pattern are simulated. The 8x8 array achieved maximum gain of 22.3 dB at θ = -1° and SLL of -15 dB.