Increasing TWTs' electronic efficiency

2016 ◽  
Author(s):  
Yuriy N. Pchelnikov
Keyword(s):  
Electronic Efficiency

Theoretical Analysis of Fowler Nordheim Parameterization and RLC Characteristics for Ring Cathode Field Emitter Arrays for Next Generation RF Amplifiers

1998 ◽  
Vol 509 ◽  
Author(s):  
K. L. Jensen
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Drive Power ◽  
Promising Alternative ◽  
Field Emitter ◽  
Field Emitter Arrays ◽  
Vacuum Microelectronics ◽  
Average Current ◽  
Output Amplifier ◽  
Electronic Efficiency

AbstractOf all applications for which field emitter arrays (FEAs) are being designed, RF vacuum microelectronics is the most technically challenging application. The current density is typically three orders of magnitude larger than that required for displays (which require < 0.1 A/cm2). Due to their high current density capabilities and instant turn-on, FEAs may be a promising alternative to thermionic emitters for use in Inductive Output Amplifiers (IOAs). An analytical model of a field emitter is used to estimate Fowler Nordheim A and B parameters, effective resistance and capacitance of the array under several GHz modulation, signal propogation lengths, total current and current density, and effects of emitter non-uniformity on the basis of array geometry and materials. Estimates of inductance, resistance, and capacitance are made to estimate the drive power required to produce a bunched electron beam for Inductive Output Amplifier applications. An electronic efficiency of 32% with 15 dB gain may be possible from an array producing 260 mA peak, 71 mA average, current at 10 GHz using a TWT helix 1.51 cm long.

scholarly journals Study of an Attenuator Supporting Meander-Line Slow Wave Structure for Ka-Band TWT

Electronics ◽  
2021 ◽  
Vol 10 (19) ◽  
pp. 2372
Author(s):  
Hexin Wang ◽  
Shaomeng Wang ◽  
Zhanliang Wang ◽  
Xinyi Li ◽  
Tenglong He ◽  
...  
Keyword(s):  
Slow Wave ◽  
Maximum Output Power ◽  
Copper Film ◽  
Wave Structure ◽  
Slow Wave Structure ◽  
Maximum Output ◽  
Ka Band ◽  
Thin Copper Film ◽  
Electronic Efficiency ◽  
Meander Line

An attenuator supporting meander-line (ASML) slow wave structure (SWS) is proposed for a Ka-band traveling wave tube (TWT) and studied by simulations and experiments. The ASML SWS simplifies the fabrication and assembly process of traditional planar metal meander-lines (MLs) structures, by employing an attenuator to support the ML on the bottom of the enclosure rather than welding them together on the sides. To reduce the surface roughness of the molybdenum ML caused by laser cutting, the ML is coated by a thin copper film by magnetron sputtering. The measured S11 of the ML is below −20 dB and S21 varies around −8 dB to −12 dB without the attenuator, while below −40 dB with the attenuator. Particle-in-cell (PIC) simulation results show that with a 4.4-kV, 200-mA sheet electron beam, a maximum output power of 126 W is obtained at 38 GHz, corresponding to a gain of 24.1 dB and an electronic efficiency of 14.3%, respectively.

scholarly journals Multibeam spherotron

Doklady BGUIR ◽  
2020 ◽  
Vol 18 (4) ◽  
pp. 5-12
Author(s):  
A. A. Kurayev ◽  
V. V. Matveyenka
Keyword(s):  
Electron Beams ◽  
High Strength ◽  
Outer Sphere ◽  
Magnetic Systems ◽  
Spherical Resonator ◽  
Synchronous Interaction ◽  
Inner Sphere ◽  
High Pulse ◽  
Electronic Efficiency ◽  
Beam Currents

The article proposes two types of multibeam spherotron-diotron based on a two-spherical resonator (an early article suggested a spherotron-diotron with non-synchronous interaction on a bi-spherical resonator, where the electron beam in this generator passes along the resonator z axis from the outer sphere to the inner one and interacts with the longitudinal (axial) electric resonator field). The first spherotron type has electron beams going from outer to inner sphere with slope ϧ about the z-axis: ϧ=0, π/8, π/4. The electrons interact with the resonator field through the emergence of quadratic forces in the field increasing along the electron motion. The second type (inverted spherotron) has electron beams located in half arc of the equatorial resonator plane, and the electrons move from the inner sphere to the outside. The interaction in it is carried out due to the spatial electron phasing. Both spherotron types achieve efficiency of 30 % at ultra-high pulse power and tens of kuloampère of total beam currents. The data presented in the article indicate the prospects of broad application for the inverted spherotron by the following indicators: extreme ease of design; no precision gratings or combs are required with a step significantly shorter than the wavelength; no focusing magnetic systems are required; electronic efficiency from 26 to 45 % is ensured. Note that the spherotron is fundamentally a highpower device (10-100 MW in a 1-10ns pulse) for in order to maintain the efficiency of non-synchronous interaction, one needs a high strength of the electromagnetic field, which is achieved only with a high-power device.

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