A high voltage bipolar pulse generated by self-breakdown switch filled in nitrogen and radiated by coaxial-conic antenna is described. It consists of the pulse power systems, switches, bipolar pulse forming line(BPFL) and UWB antenna. The bipolar pulse with the voltage～±100kV, duration≤3.6ns and pulse rate single, 10Hz and 100Hz is realized; and the radiation from the antenna with bandwidth from 150MHz to 1GHz, and peak power radiated efficiency ～６５％ has been obtained. The results of the numerical simulation of the UWB antenna practically coincided with the experimental one ．