Millimeter-wave Bragg diffraction of a micro-fabricated crystal structure

A millimeter-wave Bragg diffraction is described at 94 GHz by placing a model crystal in a parallel-plate waveguide, a crystal that is composed of dielectric rods by micro-fabrication or just metal stubs. In previously published designs, the angle occurring peak intensity could not match well with the Bragg´s law because the multiple scattering is not negligible. The problem can be solved by reducing the scattering amplitude of the crystal, i.e. controlling the radius of dielectric rod or the height of metal stub, which is verified by the experiments as well as the simulation. This study offers a design guide for the instructional laboratory equipment and allows teachers to educate the students about the concepts of scattering and diffraction and millimeter-wave knowledge.