Abstract
The Cerenkov radiation emitted by a fast charged particle moving through one medium and in the vicinity of another medium has been theoretically investigated, employing the invariance of the phenomenological electrodynamic equations of Maxwell. A simple geometry has been considered, this being the case of two coaxial dielectrics and permeable cylinders with a common cylindrical interface and a charged particle moving along their common axis. The results obtained have been discussed with special reference to the case of Cerenkov radiation at microwave and radio-frequency regions. The effect of the phenonema and coherence on the output of the emitted radiation in these cases has been briefly outlined.