Error analysis of rectangular waveguide probe with finite flange for nondestructive EM-properties and thickness measurement

In this work, open-ended waveguide probe is studied using Finite Difference Time-Domain (FDTD) technique to investigate the influence of ground-plane size on the input reflection coefficient of the probe. Variations in the ground-plane size for different materials and frequencies are simulated. In comparison with the analytical model results, it is found that using of waveguide probe with finite flange affects the input reflection coefficient substantially in some cases. Simulation results have shown that the consideration of ground-plane is large enough for the practical purpose to be infinite is restricted by the constitutive parameters and thickness of the material under test as well as the operating frequency. The FDTD simulations and experiments results are presented.