W-Band 1-kW Staggered Double-Vane Traveling-Wave Tube

$W$ -Band Multiple Beam Staggered Double-Vane Traveling Wave Tube With Broad Band and High Output Power

“…Then many studies have been performed with such a structure [12]- [14]. Also, a similar study has been done in W -band [15], and simulation shows that it can obtain a 1-kW output power from 90 to 95 GHz with a uniform longitude magnetic field of 1.3 T using a 119.436-mm SWS. However, the key challenge is the diocotron instability during the formation and focus of the sheet electron beam, which results in beam distortion, deformation, kinks, vortices, and filaments, significantly degrading the beam shape and transport, especially with a high current density in a long structure [16].…”

“…Multiple beam and sheet beam are two kinds of methods to get high power with a low beam current at high frequency in TWT [18]. Compared with the sheet beam, the multiple beam TWT can have both advantages of an easily designed coupler [15] and solving the problem of beam transmission and focus. Nowadays, several multiple beam TWTs have been studied [19]- [22] using different schemes, and a multiple beam TWT with folded waveguide circuit has been fabricated and tested at 220 GHz with a 56-W output power at Northrop Grumman [23].…”

“…6. The average interaction impedance of the 15×5 points on the sheet beam cross section in [15] are also calculated, whose height of the beam tunnel is almost equal to the diameter of our pencil beam tunnel. And the normalized phase velocity relative to the center frequency of the two SWS is compared in Fig.…”

“…A good coupler is needed to be designed to decrease the refection of the TWT, Lai et al [15] and Shin et al [25] have designed several good couplers for a sheet beam TWT. But, for the sheet beam TWT, the RF signal is not naturally cut off in the sheet beam tunnel; they have to design an input/output connector in their coupler to prevent RF signal from entering the electron gun, which lead the coupler to be somewhat too long for the beam transport and too complex to be fabricated.…”

A 140 GHz staggered double vane backward wave oscillator

“…In 2008, the staggered double vane structure was used as the RF circuit for a 220GHz TWT by Shin et al [6] and their simulation results show that the tube can offer much higher power in a wide frequency band over traditional pencil beam devices. In our previous work, the staggered double vane structure was discussed by the investigation of a W-band TWT [7]. In this study, it was employed as the slow wave circuit for designing a 140GHz sheet beam BWO.…”