4. Design a rectangular waveguide with dimensions a=2.3 cm and b=1.1 cm using EM simulation software for TE 10. TE20 and TM11 modes at 9 GHz. Simulate your designs for air-filled (1) and dielectric-filled (-4) waveguides. Comment on the results. Hint: You can choose waveguide material as perfect conductor. a) Find surface currents on waveguide walls for three modes. b) Find electric and magnetic field lines in waveguide for three modes. c) Find electric field lines at f= 4 GHz for all modes. Comment about it if you change dielectric constant, r. d) If the waveguide is lossy, repeat a and b for one mode. b Er B Figure 2