Fig. 1. Schematic diagram of the TM₀₁ mode selection coupler and its working principle

Fig. 2. Cross-sectional E-field of TM₀₁ mode and TE₁₁ mode in circular waveguide

Fig. 3. Simulation model for the single-arm four-aperture directional coupler

Fig. 4. Coupling degree and directivity of coupler vary with the number of coupling apertures

Fig. 5. Result of simulation of single-arm four-aperture coupler

Fig. 6. Magic T network

Fig. 7. Simulation results of magic T network

Fig. 8. Coupling degree of each mode in the coupler

Fig. 9. E-field distribution of the coupler at 16 GHz

Fig. 10. Image and coupling measurement schematic of fabricated mode selector coupler

Fig. 11. Measurement setup of coupling about different modes

Fig. 12. Calibration curve of mode selector coupler

Fig. 13. Setup of HPM test

Fig. 14. Typical measured waveforms of the generated microwave