Integrated Waveguide-in-Radome Antenna for V-band In-Cabin Automotive Radar Applications

Abstract

The concept of an integrated waveguide-in-radome antenna is introduced. Even though this concept could be helpful for 76 GHz automotive radar or industrial applications at 120 or 140 GHz, an exemplary design for automotive in-cabin MIMO radar application is presented. The radiator consists of a slotted waveguide antenna manufactured and metalized over the inner surface of the radome. By placing the radome over the metallic ground plane of the printed circuit board, a waveguide is obtained, which routes the signal from the MMIC output to the different radiators of the MIMO antenna. Furthermore, an AMC surface is included to cancel parasitic waves propagating through the radome and improve the radiation characteristics. Excellent free space performance is achieved in the 59-64 GHz band, with impedance bandwidth up to 15%, a FOV of 120° in all planes, and a radiation efficiency of 83%.