Design, fabrication, and characterization of engineered materials in the microwave and millimeter wave regime

We present the study of a two-dimensional square-lattice photonic crystal with all-angle negative refraction in its first band. Using this photonic crystal, we designed and fabricated a flat lens functioning as a cylindrical lens, by increasing the vertical dimension of the photonic crystal. Two-dimensional finite-difference time-domain simulation validated negative imaging and sub-wavelength resolution. To perform the experiment, a microwave imaging system was built based on a vector network analyzer. Field distributions were acquired by scanning the imaging plane and object plane. The experiment demonstrated negative refraction imaging in both amplitude and phase, and verified sub-wavelength resolution.