The resonant modes, which are excited at the shielded dielectric hemisphere, are investigated by the theoretical and experimental methods. The low-Q-factor modes of air cavity and high-Q-factor whispering gallery modes of dielectric structure are existed together in the case of high radial index value. The Q-factor value of the whispering gallery modes of the shielded dielectric sphere with the certain correlation between the sizes of dielectric hemisphere and metal shield can be more great than the Q-factor of the whispering gallery modes of the similar open dielectric resonator
