Fig. 1. Antenna profile

Fig. 2. Mode coupling of single step waveguide

Fig. 3. Multistep discontinuous geometry

Fig. 4. Stepped semicircular waveguide radiator

Fig. 5. Numerical calculation of S parameters

Fig. 6. Numerical calculation of patterns

Fig. 7. Power divider profile

Fig. 8. Electric field distribution of power divider

Fig. 9. Power divider S parameters

Fig. 10. Power divider transmission phases

Fig. 11. Electric field distribution of the antenna at a given time

Fig. 12. Antenna S parameters and gain curve vs. frequency

Fig. 13. Distribution of the antenna's maximum electric field