Simulation of TE_6,2-to-Gaussian mode launcher for a millimeter-wave gyrotron

Abstract

The short-length TE_6,2-to-Gaussian mode launcher for a millimeter-wave transverse output gyrotron was designed and simulated using two different software tools, namely Launcher Optimization Tool (LOT) and Surf3d. The geometrical parameters were calculated using geometric optics theory and the dimensions were optimized using the tools: LOT and Surf3d to achieve maximum possible (>95%) energy conversion and Gaussian fit. The launcher length to cut length ratio has been optimized as 4.15, taper angle 0.23° and the helical cut angle 70.6° for achieving energy conversion of 96 and 97%, and Gaussian fit of 98 and 97%, respectively, using LOT and Surf3d. Further, the radial variations in azimuth as well as in axial direction due to dimpled profiles obtained using the two tools were compared.

Keywords:

• Millimeter-wave gyrotron
• transverse output gyrotron
• internal mode converter

Acknowledgment

The authors are thankful to Director, Microwave Tube Research and Development Centre, Bangalore for his support and permission to publish this work.