Alternative Material Parameters for Transformation Electromagnetics Designs

A method to find alternative material parameters for 2-D transformation electromagnetics (EM) devices is presented. The alternative material parameters support exactly the same field pattern as the original ones of the transformation EM device. The same method is extended to design dual functional transformation EM devices that combine the characteristics of two separate transformation devices into one. Analytical calculations are shown and the results are verified through the full-wave simulation of well-known transformation EM devices: an electromagnetic field rotator and a cylindrical electromagnetic field concentrator. Although the transformation EM devices possessing alternative material parameters only work for a particular illumination direction, the method presented will find application in the design of antennas and beam-forming networks with a fixed feed position.