Wave propagation in complex structures has received growing interest over the last years. New analytical and numerical tools and methods are needed to better understand, analyze and simulate arising physical phenomena such as band gaps, artificial magnetism and negative refraction. Topics include homogenization, Bloch-wave analysis and radiation conditions as well as numerical multiscale methods and discretization methods for wave propagation problems in frequency and time domain. This workshop wants to bring together researchers from analysis and numerics to discuss recent developments in this field and exchange their ideas. The program includes scheduled talks by invited experts and young scientists and allows ample time for discussion. This is a closure workshop of the DFG-project "Wave propagation in periodic structures and negative refraction mechanisms".