S-Parameter Coupling in a Stepped Waveguide Section

Calculate the transmission and reflection for a stepped waveguide transition from the Ku- to X-band. Use two solver methods, the method of moments (utilising waveguide ports) and the finite element method (utilising FEM modal ports).

The waveguide consists of a Ku-band section and an X-band section. Only the H10 mode with cutoff frequency, f c = c 0 2a =9.4871 GHz is considered.

The Ku-band section dimensions are as follows:
  • a = 15.8 mm
  • b = 7.9 mm
The X-band section dimensions are as follows:
  • a = 22.9 mm
  • b = 10.2 mm

Calculate S-parameters from the cutoff frequency to 15 GHz.

Figure 1. 3D view of the waveguide step in CADFEKO.