Study of Graphene-SOI-Based Micro-Ring Resonator for Beamforming Automotive Radars

The development of autonomous vehicles has generated a need for, among others, improving detection and ranging accuracy. Beamforming radars based on electrical solutions are relevant as they can allow informative 4-dimensional (4-D) measurements. However, their bandwidth is limited due to the beam squint. To resolve this problem, optical delay lines (ODLs) based on micro-ring resonators (MMRs) are a promising solution. In this paper, we study the MMR as key ODL building block for future self-driving vehicles requiring radar-based sensing. To allow for continuous delay tuning, MMR based on graphene-silicon waveguide structure is considered. Results show that, for an MMR radius of 20 µm, the delay can be tuned in a range of 10ps for a voltage range of the graphene of 0.1 V, providing a flat delay range of 1.5 GHz.