Cosimulation and Cold Test Verification of a 220-GHz Sheet Beam Traveling-Wave Tube Amplifier

The design and cold test verification for a220-GHz sheet beam traveling-wave tube (SB-TWT) are pre-sented in this article. Although there are numerous studiesregarding the design and simulation of SB-TWTs, most ofthem focus on the research of one or several component(s)of the SB-TWT. And, the beam-wave interaction simula-tions are generally based on ideal situations, for example,an ideal electron beam and an ideal focusing magneticfield. In order to improve the accuracy of the simulationpredictions, two measures have been implemented in thisstudy: 1) the beam-wave interaction cosimulation of theentire tube is carried out, in which the sheet electron beamgenerated by the electron gun (E-Gun) and the focusingmagnetic field produced by the periodically cusped mag-netic focusing structure are employed and 2) the remod-eled high-frequency system based on the cold-cavity testresults is used for the beam-wave interaction simulation. In addition, the high-frequency system's microfabrication andcold test are also presented. Measured S-parameters of the high-frequency system showed a 3-dB transmission band-width of similar to 35.3 GHz (222.5-257.8 GHz). The beam-wave interaction cosimulation, employing the aforementioned measures, predicted an output power exceeding 85.8 W within a bandwidth of 20 GHz (220-240 GHz), accompanied by a corresponding gain of >= 22.45 dB.