Abstract: A simple ultra-wideband transverse electromagnetic(TEM)horn antenna is proposed for the asphalt pavement investigation.Comparing with the conventional TEM horn antenna design in a large size，the size of the proposed antenna is effectively reduced and the impedance bandwidth is largely extended through the proper exponentially-tapered structure and loaded absorbing material.Simulated and measured results show that the proposed TEM horn antenna has a low voltage standing wave ratio below 2 over the whole band from 0.83 to 12.8 GHz，good radiation characteristics and small late-time ringing，which can well meet the requirements of the ground penetrating radar（GPR)system.