Experimental study on transient establishment of negative refraction

A negative refraction interface composed of a positive and negative refractive index material is realized by using two-dimensional transmission line grids. The transient interface reflection and refraction properties are studied by time-domain method where the time evolution of an electromagnetic wave as it hits the interface is simulated and measured. It is found that the wave is trapped temporarily at the interface, reorganizes, and after a certain time, the refractive wave front moves eventually in the negative direction. What´s more the refractive wave need longer time to build up than the reflected wave. Experiment results agree well with the simulations.