Design of a waveguide tapering device via coordinate transformation

Complex electromagnetic structures can be designed by using the powerful tool of spatial coordinate transformation. In this study, we define a spatial coordinate transformation which shows the possibility of designing a taper between two waveguides with different dimensions; one waveguide is 11 times wider than the other. Both a continuous and a discretized model is presented and we propose achievable values of permittivity and permeability that can be obtained with existing well-known metamaterials. The performances of such a defined structure are demonstrated by finite element numerical simulations.