By reducing the pulse width of high intensity electric field from nanosecond to sub-nanosecond or picosecond level，it will lead the research of pulses on the structure and function of organisms to a new field. Based on the geometry characteristics of ellipsoid，an Impulse Radiating Antenna composed of an ellipsoidal reflector and a cone radiator was proposed，which could transform the high-intensity picosecond electric pulses to superficial layer of organisms, then kill tumor cells non-invasively. Simulation analysis shows that the electric field of ultra-short pulses are focusing effectively with high amplitude，while the gain and E-field pattern of the Impulse Radiating Antenna are stable. In addition，the Voltage Standing Wave Radio is less than 2 and the return loss is less than －10dB，all of which meet the design requirements of ultra-wideband time domain antennas.