We have ground-based radar systems, such as the Space Fence, designed to detect pieces down to around 10 cm. Ideally, putting an antenna in space to track debris that is also in space makes intuitive sense. Traditional space antennas are subject to the tyranny of the fairing - basically they have to be able to fit inside the fairing space (i.e. He’s most famous for his work on electromagnetic metamaterials and was part of the team that created the first functioning "invisibility cloak" for microwaves. And if a giant radar antenna assembled out of advanced electromagnetic materials in space by robots doesn’t sound like a fantastical idea, it's unclear what would be.