Circular waveguide mode converters at 140 GHz
Abstract
A unified derivation of the coupled mode equations for circular waveguide is presented. Also, approximate design criteria for TE/sub 0n/ to TE/sub 0n'/ axisymmetric, TE01 to TE11 wriggle, and TE01 to TM11 bend converters are reviewed. Numerically solving the coupled mode equations, an optimized set of mode converters has been designed for conversion of a 2 millimeter wave TE03 mode into TE11. This set consists of axisymmetric TE03 to TE02 and TE02 to TE01 converters followed by a wriggle TE01 to TE11 converter. This mode converter set was fabricated and tested using a 3 kW, 137 GHz gyrotron. A TE11 mode purity of better than 97% was achieved. The TE01 to TE11 wriggle converter was experimentally optimized for a measured conversion efficiency of better than 99% not including ohmic losses.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- January 1986
- Bibcode:
- 1986STIN...8630953T
- Keywords:
-
- Circular Waveguides;
- Cyclotron Resonance Devices;
- Microwave Equipment;
- Mode Transformers;
- Propagation Modes;
- Efficiency;
- Mathematical Models;
- Electronics and Electrical Engineering