Low-frequency, multigigawatt microwave pulses generated by a virtual cathode oscillator

Abstract

An axially extracted virtual cathode oscillator driven by a 4 MV, 80 kA elecron beam has been used to generate microwave pulses with an average peak power of 7.5 GW at a frequency of 1.17 GHz. Peak power efficiency was 5.3% and energy efficiency was 2.3%.

Generalized space-charge limited current and virtual cathode behaviors in one-dimensional drift space

“…10 Boers 11 and Jory 12 have presented pioneering works on relativistic SLC for a planar diode through complex expressions, such as a power series and several special functions, respectively. With the extension of the applications of virtual cathode oscillations into a relativistic range, [13][14][15][16] simple general analytical relativistic solutions for SLC and analytical descriptions of virtual cathode behavior are highly in demanded as basis for facilitating estimations and further theoretical research on space-charge limited electron beam generation, modulation, and microwave generation.…”

Analysis of Output Power Delay in Coaxial Vircator

“…Most vircators consist of an electron-beam diode and a waveguide with the configuration shown in Fig. 2(a) [9][10][11][12][13]. The electron beam is accelerated in the axial direction and is injected through the end wall of the waveguide.…”

High-efficiency virtual cathode oscillator with photonic crystal

“…[16][17][18][19][20][21][22] Along with advantages of VCOs such as high output power, construction simplicity, and capability to operate without application of the external magnetic field, one of the weakest points of vircators is low generation efficiency (0.1%-10%). 7,14,[23][24][25] In basic VCO configurations, this issue is related to low efficiency of microwave output systems or poor bunching of electrons in the VC area. 7,13,26,27 Various modifications of standard vircator design have been proposed and investigated to improve microwave generation efficiency.…”