Development of novel traveling wave tube amplifiers for V-band microwave power modules (MPMs) at the Northern Illinois University (NIU)

We examine various schemes of novel traveling wave tube (TWT) amplifiers at the Northern Illinois University (NIU) in an effort to develop a compact, high power V-band microwave power module using small signal theory and particle-in-cell (PIC) simulation. Our prior work includes theoretical and numerical assessment on performance of the aluminum-nitride (AlN)-loaded multi-beam TWT circuit, indicating that the TM₃₁-mode is amplified with 15-20 dB/beam at 64-84 GHz with three elliptical beams, simultaneously suppressing lower order modes (TM₁₁, and TM₂₁). The same analysis also shows that cascading 6-7 slow wave circuits in tandem also enables 50 W of output power with 30 dB gain, which could be integrated on a single board substrate with multi-beam emitters by micro-fabrication. More schemes to improve device performance and to reduce physical sizes are continuously explored in advancing millimeter and sub-millimeter vacuum electronics.