Design and Demonstration of a D-Band Scanning Lens Array for Automotive Radar Applications

Abstract

This work presents a lens-based antenna array that can continuously scan a directive beam with a two-way half power beamwidth (HPBW) of the order of 1° for automotive radar applications. The lens array is optimized to perform continuous beam steering in a 20° field of view (FoV), when fed using beamforming techniques that control the amplitude and phase of the array elements. A computational model for deriving the optimal weights is developed, based on a bidirectional ray-tracing methodology that accounts for the antenna radiation characteristics. To further enhance antenna performance, key design parameters including inter-element spacing, vertical displacement, and lens geometry are optimized to reduce grating lobes and mitigate scan loss. The proposed design is validated through full-wave electromagnetic simulations and experimental measurements in D-band on a fabricated 1×4 lens array prototype, with a 1×4 antenna array in-package exciting each lens. The results demonstrate high gain and effective beam steering within the desired FoV, confirming the viability of the approach for high-resolution remote sensing applications in the sub-THz band.