TE₀₁-TE₁₁ mode converter of variable-period gyroklystron

For the shortcomings of large size and narrow band width, a variable-period serpentine circular waveguide mode converter is proposed to realize high efficiency conversion of TE01 to TE11. According to the coupled wave equation, the optimal configurations of a variable-period converter and a traditional one (their radii are all 16 mm) are respectively obtained to realize the optimal mode conversion at 30.5 GHz. Calculation results show that the variable-period converter with a optimal length of 1 056.97 mm, realizes a TE11 conversion efficiency of 98.1% with its TE11 conversion bandwidth over 90% being 3.3%. However, the traditional converter with a optimal length of 769.53 mm, realizes a TE11 conversion efficiency of 99.3% with its TE11 conversion bandwidth over 90% being 5.9%. The variable-period converter assumes evident advantages in size and bandwidth over the traditional one. Test results indicate that the variable-period converter acts very well in conversion of TE01 to TE11 mode.