Author_Institution :
Naval Res. Lab., Washington, DC, USA
Abstract :
The applications of advanced engineering materials in modern vacuum electronic devices are reviewed. Unique materials with desirable thermal, mechanical, electrical, and magnetic properties are playing a crucial role in raising the average power capability, bandwidth, and efficiency of microwave and millimeter wave amplifiers and oscillators. Five major materials-related topics and technologies are covered in this article: diamond electromagnetic windows and electrode supports; electromagnetically lossy composite ceramics for control of instabilities; methods of cooling metal structures; pyrolytic graphite beam collectors and electron-gun modulation grids; and rare-earth permanent magnets for confining electron beams. For each topic, this article reviews the background physics. describes the importance of the technology to vacuum electronics, presents illustrative examples of how such technologies perform, and reviews current results from the literature
Keywords :
microwave tubes; millimetre wave tubes; vacuum tubes; diamond electrode support; diamond electromagnetic window; electromagnetically lossy composite ceramic; electron beam confinement; engineering materials technology; instability control; metal structure cooling; microwave amplifier; microwave oscillator; millimeter wave amplifier; millimeter wave oscillator; pyrolytic graphite beam collector; pyrolytic graphite electron gun modulation grid; rare earth permanent magnet; vacuum electronic device; Bandwidth; Magnetic materials; Magnetic properties; Materials science and technology; Microwave amplifiers; Microwave devices; Millimeter wave technology; Power amplifiers; Power engineering and energy; Vacuum technology;
