EMP simulators are used to test and harden electronic systems in an intense electromagnetic pulse. A horizontally polarized bounded-wave EMP simulator is designed based on a bicone-plate antenna structure, which combines the strengths of traditional bounded-wave simulators and radiating-wave simulators. Simulation and experiments are conducted to study the characteristics and the distribution of the radiation field. The results show that the simulator can generate horizontally polarized electromagnetic pulse and the waveform is double-exponential with a rise time of (2.5±0.5) ns and a pulse width of (23±5) ns. The simulator has a working volume of 5 m×3 m×2 m in which the electric field is no less than 50 kV/m within a 6 dB tolerance. Moreover, the simulator is flexible to increase the working volume while decreasing the field intensity.