We report our studies on the new designed magnetron-type microwave cavity operating in the TE011-like mode, at the rubidium hyperfine ground-state frequency of about 6.835 GHz. The properties of the cavity resonance were studied as a function of cavity temperature. Numeri-cal FEM simulations were performed and compared to the experimental results. They shed light on the influence of different design parameters on temperature-dependent behavior of the cavity.