<i>Ka</i>-Band Low-Voltage Multiple-Beam Mini-TWT
Colin D. Joye, Alexander N. Vlasov, R. Jaynes, Igor A. Chernyavskiy, Khanh T. Nguyen, John Pasour, John Rodgers, Franklin N. Wood, Vadim Jabotinski, Thomas M. Antonsen, Simon J. Cooke, Alan M. Cook, B. Levush
Abstract
We describe the design, development, and initial testing of a very compact, multiple-beam folded-waveguide traveling wave tube (TWT) operating in Ka -band at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim $ </tex-math></inline-formula> 6 kV. A proof-of-principle four-beam, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim $ </tex-math></inline-formula> 100 mA/beam device has been fabricated and tested, and a 16-beam version of the device has been designed and is predicted to produce an output power up to 1 kW. Here, we describe the design approach we devised and implemented to overcome two fundamental challenges: 1) generating and transporting the tightly spaced beams required to operate in the millimeter-wave regime and 2) developing folded waveguide circuits that can provide high interaction impedance for each of the beams as well as stable operation in a dense high-order-mode environment.