Enhanced transmission through the topology optimized sub-wavelength aperture with maximum transmission efficiency

Abstract We reported an efficient enhanced transmission (ET) through a sub-wavelength aperture, whose configuration was designed based on topology optimization. The configuration of the original aperture was modified with the coplanar metallic patches and the planarization of the perforated metallic plate was not destroyed, so that the miniaturization of the ET component was guaranteed. The topology optimization model for designing the coplanar aperture microstructure (CAMS) to produce ET with maximum efficiency at the required frequency was established. The sensitivity analysis on each patch of the designed microstructure was also carried out in the design, which indicated the impact on the transmission characteristics from the removal of each patch. According to the basic optimization model, the aperture designing method for the ET under the constraint of irregular (discontinuous) aperture was also discussed. Both the simulation and experimental results validated the feasibility of the proposed optimization model.