A high power UWB system with subnanosecond rise time using balanced TEM horn antenna

High power ultra wideband (UWB) systems can be used for various applications like buried target detection, electrical characterization of materials, space debris detection and as a source for vulnerability studies on electronic circuits. A high power UWB radiator system is developed at BARC, Mumbai. This is a 120 kV, 66 Ohm system which can generate intense electromagnetic fields. Any UWB system consists of pulse power system and antenna. Pulse power system for this radiator consists of a Marx Generator and a pulse forming line which can generate a 110 kV, 5 ns pulse with a rise time of ~ 400 picoseconds. A balanced TEM horn type antenna was used in this system. Impedance of this antenna is matched to feed i.e. 66 Ohms at feed end and then gradually varies to match with free space impedance. This antenna can effectively radiate this kind of sub-nanosecond rise time pulse. Designed antenna has an acceptable performance in terms of VSWR in desired frequency range of 150 MHz to 1 GHz depending on pulse parameters. This paper discusses the overall system performance with an emphasis on antenna design details and results.