Effect of Thermal strain in helical slow-wave circuit on TWT Cold-test characteristics

The heat transfer analysis presented in this study deals with the thermal performance of the helix slow-wave circuit for TWT. The current paper estimate the temperature of helix accurately through finite element software ANSYS. The expansion of rods makes the helix concave or convex at different position. Thermal strain made the radius of the tape increased overall, so the phase velocity decreases as the temperature of helix gets higher. But the impedance keeps almost the same value as the temperature increasing. Based on this kind of information, manufacturers can adjust and optimize the designs of devices before fabrication.