Caltech's approach[0] is to make their satellite with solar panels on one side and a transmit antenna on the other, so pretty much the whole area of solar panel

Caltech's approach[0] is to make their satellite with solar panels on one side and a transmit antenna on the other, so pretty much the whole area of solar panels serves as a giant phased array transmit aperture. They claim that this approach can be made very lightweight and might only mass 160 g/m^2. Kilometer space structures need not be very massive, as the loads they are subject to are quite small. More often achieving a certain stiffness, such that the structure doesn't wobble around too much when being repointed, drives design more than resisting structural loads. The main loading case they consider in [0] is solar radiation pressure. Making the entire structure coherent gets interesting as it's expected to flex a bit. However, they have demonstrated methods to correct for this flex[1]. One problem they have is that their satellite has to consist of a number of smaller spacecraft connected to each other in a grid because they can't launch the whole structure at the same time. One person involved with the project had concerns about how they would align each spacecraft to within subwavelength accuracy. [0]https://arxiv.org/ftp/arxiv/papers/2206/2206.08373.pdf https://arxiv.org/ftp/arxiv/papers/2206/2206.08373.pdf [1]https://www.nature.com/articles/s41528-022-00218-z https://www.nature.com/articles/s41528-022-00218-z