Exemplary embodiment can utilize the properties of tunable thin-film, material (e.g., graphene) to efficiently modulate the intensity, phase, and/or polarization of transmitted and/or reflected radiation, including mid-infrared (“mid-IR”) radiation. Exemplary embodiments include planar antennas comprising tunable thin-film material sections and metallic sections disposed in contact with the tunable thin-film material sections, each metallic section having a gap with at least one dimension related to a wavelength of the radiation, which in some embodiments may be less than the wavelength. The metallic layer may comprise rods arrange in one or more shapes, or one or more apertures of one or more shapes. Embodiments of the antenna may also comprise a substrate, which may be a semiconductor or conductor in various embodiments. Embodiments also include systems, computer-implemented methods, devices, and computer-readable media for effectuating desired modulation of incident radiation by, e.g., varying the doping level of the tunable thin-film material.