Finite-Difference Time-Domain(FDTD) method and Finite-Difference Frequency-Domain(FDFD)
method are widely used to analyze transmission characteristics of many transmission systems. Based on 2-D FDFD
method, general analysis formulas for the circular ridged waveguide are derived. The proposed method is effective for
almost ridge structures, if the boundary condition changed accordingly. To confirm this method, a number of numerical
results are achieved and compared with others using different methods. Good agreements are gained, which
demonstrates the accuracy of 2-D FDFD method. Also the method is not time-consuming, which indicate the efficiency.