A UTD（Uniform Geometrical Theory of Diffraction） is developed for the HF electromagnetic radiation and diffraction field from slot on a conducting convex surface coated with a dielectric layer. With the aid of the caonical problem UTD solution

the dyadic transfer function（DTF） between the source and the radiation（or diffraction） field is derived for the problem. The radiation and diffraction field are expressed by compound Fock’s functions （CFF）. The compound Fock’sfunctions reduce to the geometrical optics field in the deep lit region and are deseribed by creeping waves in the shadow region and also remain uniformly crossing the boundary between lit and shadow region.Some numerical results based on the UTD solution are given and shown to agree well with experiments or exact results.