High power microwave generation by a coaxial virtual cathode oscillator

Jiang, Weihua; Woolverton, K.; Dickens, J.; Kristiansen, M.

doi:10.1109/27.799836

Cited by 80 publications

(30 citation statements)

References 6 publications

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“…5, from which we obtain the microwave frequency of ∼2.1 GHz. This frequency has good agreement with the measurement result [5] which is about 2 GHz. To compare the result of the simulation and the measurement, the FFT on the microwave oscillation obtained by experiment is shown in Fig.…”

Section: Oscillation Frequencysupporting

confidence: 79%

“…To compare the result of the simulation and the measurement, the FFT on the microwave oscillation obtained by experiment is shown in Fig. 8 [5].…”

Section: Oscillation Frequencymentioning

confidence: 99%

“…Experimental results of a coaxial vircator, reported by Texas Tech University team [5]. Simulation of this structure with a FDTD particle in cell code is presented and compared with experimental results [5,6].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Analysis of Output Power Delay in Coaxial Vircator

Moradi¹,

Ghorbani²,

Rahdan³

et al. 2008

PIER B

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Section: Oscillation Frequencysupporting

confidence: 79%

“…To compare the result of the simulation and the measurement, the FFT on the microwave oscillation obtained by experiment is shown in Fig. 8 [5].…”

Section: Oscillation Frequencymentioning

confidence: 99%

See 1 more Smart Citation

Analysis of Output Power Delay in Coaxial Vircator

Moradi¹,

Ghorbani²,

Rahdan³

et al. 2008

PIER B

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show abstract

“…High-power cylindrical diodes have also found application in cylindrical vircators 8 and in high-resolution radiography sources. 9 Again, as for the planar diode, the specialized literature proposes no analytical solutions for the space-charge-limited current in cylindrical diodes, but in the idealized case of 1D rectilinear flow between long coaxial cylinders.…”

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confidence: 99%

Space-charge-limited current in cylindrical diodes with finite-length emitter

Kostov

Barroso

2002

Physics of Plasmas

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In the present paper we extend to two dimensions the classical Langmuir-Blodgett law, which determines the maximum current I LB that can be accelerated by a given voltage across two infinitely long coaxial cylinders. Generalization of the I LB law is established by performing two-dimensional 2D particle-in-cell numerical experiments on a variety of cylindrical diode configurations with a finite-length emitter. It is found that the limiting current in two dimensions I 2D follows a monotonically decreasing function of the emitter length-to-outer electrode radius ratio L/R as expressed by the fitting function I 2D /I LB ϭ1ϩ0.1536/(L/R)ϩ0.0183/(L/R) 2 within 2.5% accuracy for simulation data in which the ratio of the outer to inner radii exceeds 3. © 2002 American Institute of Physics. ͓DOI: 10.1063/1.1446876͔The effect of space charge on the flow of charged particles between two parallel electrodes in vacuum is of great importance in microwave electronics, crossed-field devices, and high-power diodes. In particular, if too much charge is injected into a gap, the resulting electric field becomes sufficiently high to reflect the injected particles back to the emitter, forming a virtual cathode. Limiting currents of vacuum diodes are classical subjects with early works dating back to the beginning of the last century when onedimensional space-charge-limited flow solutions were derived. Only for simple cases, however, such as plane parallel plates, infinitely long coaxial cylinders, and concentric sphere there exist analytical solutions.1 For a planar gap with gap separation D and gap voltage V, the maximum electron current density in a space-charge-limited diode is given by the well-known Child-Langmuir law,where e and m are, respectively, the charge and the mass of the emitted particles, and ⑀ 0 is the free space permittivity. Equation ͑1͒ is derived by assuming zero electron emission velocity and neglecting relativistic effects. Later an analytical solution for limiting current of relativistic electron flow in the planar diode was found, 3 but with the generalization of Child-Langmuir law in two dimensions still remaining a formidable task analytically. So an alternative approach was adopted, namely, the use of particle-in-cell ͑PIC͒ computer simulation to investigate two-dimensional space-chargelimited flow in a planar diode.4,5 About works on cylindrical diodes, particle simulation method was successfully applied for studying the stability of divergent and convergent electron flows in 1D cylindrical Pierce diode. 6 Also numerical experiments were performed to examine electrical properties of charged-particle flows in high-power cylindrical pinchedbeam diode over a wide range of voltages. 7The electron flow between coaxial cylinders is another important topic on beam formation theory, which has laid the basis of many useful gun designs. High-power cylindrical diodes have also found application in cylindrical vircators 8 and in high-resolution radiography sources.9 Again, as for the planar diode, the specialized lit...

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“…Virtual cathode oscillator is one of the promising devices being developed as high power microwave sources [3]. Research efforts on virtual cathode oscillator have been concentrated on efficiency improvement and oscillation frequency control [4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Time-frequency analysis of virtual cathode oscillator

Jiang

2009

2009 IEEE Pulsed Power Conference

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Time-frequency analysis has been carried out for microwave radiation from a virtual cathode oscillator. The results have given clear evidence of mode hopping and frequency shifting. The dependence of mode competition on the diode operation parameters is also identified.The information obtained is considered to be very important for understanding the physical behavior of virtual cathode oscillator.

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High power microwave generation by a coaxial virtual cathode oscillator

Cited by 80 publications

References 6 publications

Analysis of Output Power Delay in Coaxial Vircator

Analysis of Output Power Delay in Coaxial Vircator

Space-charge-limited current in cylindrical diodes with finite-length emitter

Time-frequency analysis of virtual cathode oscillator

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