The authors of [1] describe an evanescent-mode waveguide filter consisting of two parallel cut-off waveguide paths with dielectrics. The proposed filter is modelled in FEKO with the extended MoM technique that allows the metallic elements for the waveguide to be modelled with the MoM and waveguide ports, while the dielectric elements are modelled with MoM SEP blocks. Figure 1 shows a lateral cut-plane view of the model with metallic elements in orange and dielectric blocks in blue. The ports are fed with FEKO's waveguide feed. As this filter is designed for a very wide band of frequencies, FEKO's AFS technology is applied to effectively select the minimum number of frequency points that will accurately characterise the filter's response.

Fig 1: Waveguide filter with dielectric blocks

Figure 2 presents a comparison between the filter's measured insertion loss (from [1]) and the FEKO computed insertion loss. The comparison is excellent, validating the applicability of FEKO to problems including waveguides and dielectric elements.

Fig 2: Insertion loss comparison - Measured vs FEKO
(a) Measured [1]	(b) FEKO simulation

References