The radiator is much more efficient than the solar panels (for obvious reasons), so that’s not the limiting factor.
As to power, Caltech is already at 2-3 pounds per square meter: https://magazine.caltech.edu/post/sspp-space-solar-power-pro...
> Another way to think about it: An SSPP spacecraft with a 60-meter-by-60-meter surface area made using today’s space PV-cell technology would cost $36 million and weigh nearly 9,000 pounds, or almost as much as a Ford F-450 truck. With the ultra-lightweight PV-cell technology Atwater envisions, it would cost just $450,000 and weigh about 300 pounds, or about as much as an IKEA three-seat sofa
That’s megawatt-level solar power under 5 tons using today’s leading edge technology. Starship super heavy can launch 100 tons into LEO.
As to bandwidth, Starlink V3 backhaul capacity is 1 terabit. Microwave radio frequencies have an insane amount of bandwidth.
The Caltech Concept is just that — a concept. No prototype, no tests, no manufacturing, no results. When they achieve this order of magnitude improvement on a prototype scale, that's when we should take them seriously.
I'm referring to the description of "today’s space PV-cell technology" (I believe the lightweight panels used to upgrade the ISS in 2021).
SSPP has already sent prototypes to space: https://www.caltech.edu/about/news/space-solar-power-project....
There's a ton of work being done on lightweight solar panels for space. E.g. https://ascentsolar.com/asti-technology-and-unique-advantage...
I have a lot of respect for Atwater but I'm pretty sure a lot of people at Caltech think this is donor driven research.