A stepped post-wall waveguide with aperture interface to standard waveguide

We have proposed the aperture coupling E-bend with step structure in which the posts around the aperture are kept away from the aperture. A 61.25 GHz model transformer gives 11.4 % bandwidth for the reflection below -25dB. The analysis results predict well the measured bandwidth for the reflection less than -15dB. We have estimated mechanical tolerances and the difference between analysis and experimental results in terms of both the conventional and proposed structures. The step structure shows stable performance against the mechanical tolerance compared to the conventional structure. The proposed structure gives a smaller difference between analysis and measurement results, so the reliability of the analysis model increases.