Polyimide aerogel with an intrinsically hydrophobic nature and a dielectric constant as low as 1.19 at a frequency of 2.75 GHz was synthesized by the polycondensation of an alicyclic dianhydride, an aromatic fluorinated diamine, and an amino-substituted polyhedral oligomeric silsesquioxane (POSS) end-capper, followed by a supercritical carbon dioxide drying procedure.