Abstract
Self-dual media (SDM) coatings provide a powerful means to enhance wave transmission through subwavelength apertures in conducting screens. When applied around an aperture, SDM suppresses reflections and directs incident electromagnetic energy exclusively through the opening. Experimental and numerical studies show that a finite, double-sided SDM coating with dimensions of about [Formula: see text] increases transmitted power by roughly 10 dB compared to an uncoated reference. This effect is non-resonant, enabling broadband operation constrained only by the material design. Unlike earlier methods that mainly improved radiation directivity without altering the transmitted power, this approach significantly boosts power density within the aperture itself. These findings highlight SDM coatings as a versatile strategy for efficient energy transmission through sub-wavelength structures, with potential applications in waveguiding, sensing, phased arrays and energy harvesting technologies.