https://arberobotics.com/product/ is one. It was rumored Tesla themselves wanted to use Arbe radars, but evidently they have ditched the plan and gone radar less. I think AutoX from China is planning to use Arbe as well.
Waymo has its own custom developed 4D imaging radar and I imagine most of the other SDC players have their own versions.
Waymo has its own custom developed 4D imaging radar and I imagine most of the other SDC players have their own versions.