Streamlined radomes of hypersonic vehicles require electromagnetic (EM) transparency, as well as thermomechanical resistance. Current design methods for high-temperature streamlined radomes are limited to single-frequency designs. This letter presents a design approach for streamlined radomes that achieve dual-band EM transparency within the 4–40GHz range, along with thermomechanical resistance. The design employs a nine-layer silicon nitride ceramic graded dielectric multilayered wall. The realistic non-uniform temperature boundary plays a crucial role, which provides a sufficiently large design space for optimizing EM performance. The designed radomes possess an average insertion loss (IL) of less than 1.00 dB along with a low boresight error (BSE). It is worth noting that the artificial intelligence algorithm accelerates the optimization process by 13 times, making the design more efficient.