Abstract: To meet the demands of compactness and miniaturization of the wideband high power microwave radiation system, an electric-magnetic vibrator combined antenna with an aperture of 20 cm20 cm is designed. By applying the 3D full wave electromagnetic field simulation tool, it is proved that the antenna voltage standing wave ratio is less than 3 and the antenna gain is larger than 2 within the bandwidth of 0.3-1.7 GHz. Meanwhile, the influences of the size of the antenna structure, the length of the current loop and the angle of the antenna aperture on the antenna impedance bandwidth and the gain are investigated. On this basis, fed by the wideband signal with a peak voltage of 226 kV for simulation, the maximum radiation factor reaches 150 kV, the equivalent radiation power reaches 358.8 MW and the radiation efficiency is 70.6%. The results indicate that the electric-magnetic vibrator combined antenna can meet the radiation requirements of the high power wideband microwave, the compactness of the radiation system and high radiation efficiency.