This paper presents an investigation of the miniaturized radiators for microwave hyperthermia. The physical models are established by using the high frequency structure simulator(HFSS) for 2.4GHz bare antenna, half-bare antenna and coaxial slot antenna for hyperthermia, and tested results using Vector Network Analyzer are also given and compared with the simulation results from HFSS, providing guidance to develop MEMS-based radiators for microwave hyperthermia.