Virtual cathode microwave devices -- Basics
Unlike a conventional microwave tube, a virtual-cathode device operates above the space-charge limit where the depth of the space-charge potential can cause electron reflection. The region associated with this electron reflection is referred to as a virtual cathode. Microwaves can be generated through oscillations in the position of the virtual cathode and through the bunching of electrons trapped in a potential well between the real and virtual cathodes. These two mechanisms are competitive. There are three basic classes of virtual cathode devices: (1) reflex triode; (2) reditron and side-shoot vircator; and (3) reflex diode or vircator. The reflex diode is the highest power virtual-cathode device. For the reflex diode the energy exchange between the beam and electromagnetic wave occurs in both the axial and radial directions. In some designs the oscillating-virtual-cathode frequency exceeds the reflexing-electron frequency exceeds the oscillating-virtual-cathode frequency. For the flex diode a periodic disruption in magnetic insulation can modulate the high- frequency microwave power. Overall, particle-in-cell simulation predictions and axial reflex diode experiments are in good agreement. Although frequency stability and phase locking of the reflex diode have been demonstrated, little progress has been made in efficiency enhancement. 58 refs., 11 figs.
- Research Organization:
- Los Alamos National Lab., NM (United States)
- Sponsoring Organization:
- DOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 5197817
- Report Number(s):
- LA-UR-91-2833; CONF-9109279--2; ON: DE92000318
- Country of Publication:
- United States
- Language:
- English
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High power microwave generation from a virtual cathode oscillator (Viracator)
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Related Subjects
426000* -- Engineering-- Components
Electron Devices & Circuits-- (1990-)
AMPLIFIERS
BEAMS
CATHODES
CURRENT DENSITY
DESIGN
ELECTRODES
ELECTRON BEAMS
ELECTRONIC EQUIPMENT
EQUIPMENT
EVALUATION
LEPTON BEAMS
MAGNETIC INSULATION
MICROWAVE AMPLIFIERS
MICROWAVE EQUIPMENT
OSCILLATORS
PARTICLE BEAMS
REFLECTION
SPACE CHARGE