Fig. 1. Schematic diagram of the input coupler

Fig. 2. Eigenvalue of TE mode vs radius ratio

Fig. 3. TE₈₁₁ propagation constant in coaxial guide and length vs raidus r_b

Fig. 4. Frequency vs outer radius r_b

Fig. 5. Coefficient S₂₁ of mode TE₀₁ and TE₀₂

Fig. 6. Dependence of parameter S₂₁ of TE₀₁mode on the length deviation of slot

Fig. 7. Dependence of parameter S₂₁ of TE₀₁ mode on the width deviation of slot

Fig. 8. Electric field profiles of input coupler in HFSS

Fig. 9. Coefficient S₂₁ of input coupler

Fig. 10. Coefficient S₁₁ of input coupler

Fig. 11. Dependence of the input coupler’s parameter S₂₁ on the miscellaneous modes

Fig. 12. Cold test of input coupler

Fig. 13. Comparison of parameter S₂₁ between HFSS simulation and cold test