Thermo-Mechanical Stress in High-Frequency Vacuum Electron Devices Diana Gamzina 1,2 & Neville C. Luhmann Jr. 1 & Bahram Ravani 1 Received: 8 May 2016 /Accepted: 1 September 2016 / Published online: 16 September 2016 # Springer Science+Business Media New York 2016 Abstract Analysis of the thermo-mechanical performance of high-frequency vacuum electron devices is essential to the advancement of RF sources towards high-power generation. Operation in an ultra-high vacuum environment, space restricting magnetic focusing, and limited material options are just some of the constraints that complicate thermal management in a high-power VED. An analytical method for evaluating temperature, stress, and deforma- tion distribution in thin vacuum-to-cooling walls is presented, accounting for anisotropic material properties. Thin plate geometry is used and analytical expressions are developed for thermo-mechanical analysis that includes the microstructure effects of grain orientations. The method presented evaluates the maximum allowable heat flux that can be used to establish the power-handling limitation of high-frequency VEDs prior to full-scale design, accelerating time-to-manufacture. Keywords Vacuum electronics . Terahertz . Thermal stress . High frequency . Anisotropic 1 Introduction 1.1 High-Frequency Vacuum Electron Devices Recent interest in high-frequency radiation sources for innovative applications (high data rate communications [1], concealed weapon detection [2], remote chemical and biological warfare agent detection [3], plasma fusion diagnostics [4, 5], remote high-resolution imaging [6], chemical and biological spectroscopy [7], deep space research [8], biomedical diagnostics [9], material research and processing [10]) has fueled research into advanced fabrication techniques and device J Infrared Milli Terahz Waves (2017) 38:47–61 DOI 10.1007/s10762-016-0312-7 * Diana Gamzina dgamzina@ucdavis.edu 1 University of California, Davis, One Shields Ave., Davis, CA 95616, USA 2 Department of Electrical and Computer Engineering, UC Davis, Davis, CA 95691, USA