We report on hot test measurements of a wide-bandwidth, 220-GHz sheet beam traveling wave tube amplifier developed under the Defense advanced research projects agency (DARPA) HiFIVE program. Nano-computer numerical control (CNC) milling techniques were employed for the precision fabrication of double vane, half-period staggered interaction structures achieving submicrometer tolerances and nanoscale surface roughness. A multilayer diffusion bonding technique was implemented to complete the structure demonstrating wide bandwidth (>50 GHz) with an insertion loss of about -5 dB achieved during transmission measurements of the circuit. The sheet beam electron gun utilized nanocomposite scandate tungsten cathodes that provided over 438-A/cm2current density in the 12.5:1 ratio sheet beam. An InP HBT-based monolithic microwave integrated circuit preamplifier was employed for TWT gain measurements in the stable amplifier operation region. In the wide-bandwidth operation mode (for gun voltage of 20.9 kV), a gain of over 24 dB was measured over the frequency range of 207-221 GHz. In the high-gain operation mode (for gun voltage of 21.8 kV), over 30 dB of gain was measured over the frequency range of 197-202 GHz. High-power tests were conducted employing an extended interaction klystron.
No takes yet. Share an insight, caveat, or question.
Baig et al. (2017) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: