High-Voltage Drivers Based on Forming Lines with Extended Quasi-Rectangular Pulses for High-Power Microwave Oscillators

Abstract

The paper considers such modifications of an ordinary pulse-forming line (PFL) as double-width and triple-width forming lines (DWFL, TWFL) built around the PFL by nesting one and two additional uncharged lines, respectively, into its free volume inside the inner conductor of the PFL. The theoretical analysis is supported by simulation and experimental data, showing that the TWFL provides a 3-fold increase in the voltage pulse width and that it can be further increased by an arbitrary integer factor k. The results of the numerical simulations also show the electric field behavior and other features, including the edge effect in the TWFL. The proposed method opens up new opportunities for designing compact high-power microwace (HPM) sources.

A Repetitive Low Impedance High Power Microwave Driver

“…The past decade has seen various custom-built HPM drivers around the world, using very different technical approaches [12][13][14][15][16][17][18][19][20][21][22], with peak power ranging from several to several tens of gigawatts. Most of the drivers have a water or oil filled coaxial or Blumlein pulse forming lines (PFL).…”

“…Most of the drivers have a water or oil filled coaxial or Blumlein pulse forming lines (PFL). For example, the very successful SINUS series accelerators from the Institute of High Current Electronics, Tomsk, Russia, featuring in transformer oil insulated PFLs with built-in Tesla transformers, have been widely used [12,13]. They are suitable for driving high impedance (>50 Ω) HPM tubes such as the BWO [23] since the suitable for driving high impedance (>50 Ω) HPM tubes such as the BWO [23] since the oil insulated PFL has characteristic impedance in the range of dozens of ohms.…”

Efficiency of moderately relativistic resonant S-band BWO

“…Further development in research field of high power microwaves radiation in various wavelength ranges is accompanied by an increase of the requirements for the parameters and the quality of high-current electron beams [7,8]. Essentially important are the problems of generating high-voltage "quasi-rectangular" power supply pulses with stable parameters, providing a flat top pulse duration and fast rise time of the pulse in a few ns [9,10], repetitively pulsed HPM generation, optimizing the profile of the guiding magnetic field to obtain electron beams with a low transverse velocity electrons β┴ with respect to their longitudinal velocity (so that β┴ 2 « 1/γ 2 ) etc. There is also the task of achieving high-efficiency generation in a BWO at a level of 1 GW at a more moderate, practically convenient electron beam energy in the range of 450-600 keV and at an electron beam power of less than 5 GW.…”