Experimental Verification of Sub-diffraction Imaging by Compensated Bilayer of Transmission Line Metamaterials

We realize the planar lens of anisotropic compensated bilayer through the implementation of anisotropic metamaterials by periodic transmission line circuits based on different unit cells of loaded microstrip grids. We report the circuit simulation and experimental results of such lens that demonstrate sub-diffraction imaging at microwave frequency under the consideration of losses in the lens. The measured half-power beamwidth of the point source image formed by the lens is 0.08 effective wavelengths, which is far beyond the diffraction limit. We also investigate the effect on imaging quality caused by the fluctuation in chip inductors and capacitors from their nominal values, which is inevitable in realistic metamaterial.