Transformation Optics and Applications in Microwave Frequencies

Modern electrical and communication technologies benefit from classical electrodynamics and electric circuits, both of which are based on the Maxwell’s equations. Using the property of metric invariance in Maxwell’s Equations, transformation optics has been proposed and achieves a rapid progress in the past decade. Transformation optics is a method for the conceptual design of complex electromagnetic media, offering opportunities for the control of electromagnetic waves. In this paper, we introduce the general theory of transformation optics and discuss the recent development on the transformation devices in the microwave band, such as non-singular invisibility cloak and its realization in dc circuit, three-dimensional ground-plane cloaks, flattened Luneburg lens, highperformance antennas, and high-resolution imaging lens. Some of the transformation-optics-based devices are expected to have further impact on the microwave engineering applications.