A Tesla Transformer and a Coaxial Peaking Switch as a UWB Pulse Source
Y. Amala, L. Pecastainga, M. Rivalettoa, T. Reessa, P. Pignoleta, B. Cassanyb, A. Silvestre de Ferronb, L. Courtoisb and E. Merleb
a Laboratoire de Génie Electrique, Université de Pau, 2 av. Angot, 64053 Pau, France,
b CEA CESTA, BP 2, Routes des Gargails, 33114 Le Barp, France
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This paper presents a high voltage pulse source which is able to generate ultra wideband (UWB) pulses during about 1 ns through a 16 antennas array. This UWB source is composed of a 50 kV DC voltage supply, a Tesla transformer to amplify this voltage up to 400 kV, a gaseous pressurized peaking switch and an impedance transformer (50 Ω → 3.125 Ω). This output impedance value corresponds to the input impedance value of a sixteen 50 Ω antennas array. That is why a distributor is needed in order to feed the antenna array. In this paper, the peaking switch and the capacitive line divider used to characterise the generated pulses are particularly described. The peaking switch is based on the principle of a line discharge by means of a high pressure gas switch. It is loaded with a Tesla transformer to obtain a good pulse reproducibility. The main characteristics of the output pulse waveform: (amplitude and rise time) are linked to the properties of the gas switch and particularly to the gap distance, the pressure and the nature of the gas used in the switch filling. The aim is to find a good compromise between various parameters as the output pulse amplitude, the rise time and the repetition rate in order to ensure a better efficiency of the UWB source. Classical voltage measurement techniques do not allow us an estimation of the main characteristics of such an output signal. Therefore a voltage probe was designed and realised to measure both the amplitude and the rise time of the pulses delivered by the generator. This device is based on the principle of a capacitive line divider. Calibration tests (transient and frequency tests) were performed and show that the high cut off frequency, around 2.5 GHz, is consistent with the transient response of the output high voltage waveform. The design, realisation and calibration tests are also presented.
DOI: 10.12693/APhysPolA.115.1115
PACS numbers: 84.70.+p, 07.57.Hm, 84.30.Ng